Field of the invention
[0001] The invention relates to methods for diagnosing or prognosing tumour properties in
a subject having a tumour, such as a breast tumour. The invention further relates
to the use of the methods to determine suitability of treatment for a subject, or
to determine efficacy of treatment in a subject, as well as to cancer treatments for
use in treating subjects having a tumour.
Background to the invention
[0002] Cancer is a major societal challenge that affects an increasing number of people.
Breast cancer, for example, affects approximately one out of eight women. Besides
the difficulties associated with prolonged treatment periods and related side effects,
there is a substantial risk that a cancer such as breast cancer will spread and cause
metastatic disease. Despite a slightly improved survival for cancer sufferers in general
there are major drawbacks with the existing therapies as they do not target the cancer
stem cell/epithelial-mesenchymal transition (EMT) niche and there is substantial under-treatment
due to lack of efficient therapies. These therapy resistant subpopulations of cancer
cells are probably responsible for malignant properties and need to be controlled
in order to prevent disease recurrences (
Conley, SJ. et al. Antiangiogenic agents increase breast cancer stem cells via the
generation of tumour hypoxia. Proc Natl Acad Sci USA 109, 2784-2789, 2012). The other problem with the existing treatment schedules for cancers such as breast
cancer is over-treatment due to lack of treatment predictive information guiding clinicians
in treatment decision and choices.
[0003] WO 2013/050962 A1 relates to an extracellular matrix composition and a tumor microenvironment platform.
WO 2015/017784 A1 relates to a 3D decellularized bone scaffold seeded with cancer cells.
US 2013/344490 A1 relates to tissue constructs comprising a decellularized biomatrix and a neoplastic
cell cultured within the biomatrix.
WO 2013/003234 A1 relates to a tumour matrix comprising extracellular matrix components from a basement
membrane, stroma and tumour.
Lü et al, "Development of an Acellular Tumor Extracellular Matrix as a Three-Dimensional
Scaffold for Tumor Engineering", PLOS ONE, vol.9, no.7, 29 July 2014, page e103672
describes the development of an acellular tumour extracellular matrix as a three-dimensional
scaffold for tumour engineering.
Cazzaniga et al, "Human Prostate Tissue-Derived Extracellular Matrix as a Model of
Prostate Microenvironment", European Urology Focus, vol. 2, no. 4, 1 October 2016,
pages 400-408 relates to human prostate tissue-derived extracellular matrix as a model of prostate
microenvironment.
Naba et al, "Extracellular matrix signatures of human primary metastatic colon cancers
and their metastases to liver", BMC Cancer, Biomed Central, London GB, vol. 14, no.
1, 18 July 2014, page 518 relates to extracellular matrix signatures of human primary metastatic colon tumours
and their metastases to liver.
Summary of the invention
[0004] In a first aspect, the invention provides a method for determining one or more tumour
properties in a human subject with a tumour, the method comprising:
- seeding a cell-free scaffold obtained from the tumour (the source tumour) with cancer
cells;
- culturing the cancer cells in the scaffold;
- assaying the cultured cancer cells for the presence of target molecules indicative
of the expression of one or more genes in the cells; and
- determining one or more tumour properties based on the results of the assay;
wherein the cancer cells are not cancer cells taken from the source tumour in the
subject.
[0005] In one embodiment, the one or more genes may be one or more markers of tumour progression.
In one embodiment, the one or more genes may be selected from Table G.
[0006] In a second aspect, the invention provides a method for determining a suitable treatment
for a human subject with a tumour, the method comprising:
- determining one or more tumour properties in the subject by a method according to
the first aspect; and
- determining a suitable treatment based on the tumour properties of the tumour.
[0007] In a third aspect, the invention provides a method for determining or monitoring
efficacy of a treatment for a human subject with a tumour, the method comprising:
- (a):
- seeding a cell-free scaffold, obtained from the tumour (the source tumour) before
the treatment has been provided to the subject, with cancer cells;
- culturing the cancer cells in the scaffold; and
- assaying the cultured cancer cells for the presence of target molecules indicative
of the expression of one or more genes in the cells;
- (b):
- seeding a cell-free scaffold, obtained from the tumour (the source tumour) after the
treatment has been provided to the subject, with cancer cells;
- culturing the cancer cells in the scaffold;
- assaying the cultured cancer cells for the presence of target molecules indicative
of the expression of one or more genes in the cells;
and
- (c) comparing the results of the assays in (a) and (b);
wherein the cancer cells in (a) and (b) are not cancer cells taken from the source
tumour in the subject.
[0008] In a fourth aspect, the invention provides a method for determining likely efficacy
of a treatment for a human subject with a tumour, the method comprising:
- (a)
- seeding a cell-free scaffold obtained from the tumour (the source tumour) with cancer
cells;
- culturing the cancer cells in the scaffold;
- assaying the cultured cancer cells for the presence of target molecules indicative
of the expression of one or more genes in the cells;
- (b) applying the treatment to the scaffold comprising the cancer cells;
- (c) assaying the cultured cancer cells after the treatment has been applied, for the
presence of target molecules indicative of the expression of one or more genes in
the cells;
and
- (d) comparing the results of the assays in (a) and (c);
wherein the cancer cells in (a)-(c) are not cancer cells taken from the source tumour
in the subject.
[0009] In a fifth aspect, the invention provides a method for determining one or more tumour
properties in a human subject with a tumour, the method comprising:
- assaying a scaffold obtained from the tumour for one or more proteins selected from
any one or more of Tables C-F; and
- determining one or more tumour properties in the subject based on the results of the
assay;
wherein the one or more tumour properties are selected from tumour malignancy grade
and tumour proliferation; and wherein the scaffold is cell-free scaffold, and the
tumour is a breast cancer tumour.
[0010] In a sixth aspect, the invention provides a method for determining a suitable treatment
for a human subject with a tumour, the method comprising:
- determining one or more tumour properties in the subject by a method according to
the fifth aspect; and
- determining a suitable treatment based on the tumour properties of the tumour.
[0011] In a seventh aspect, the invention provides a method for determining or monitoring
efficacy of a treatment for a human subject with a tumour, the method comprising:
- assaying a scaffold, obtained from the tumour before the treatment has been provided
to the subject, for one or more proteins selected from any one or more of Tables C-F;
- assaying a scaffold, obtained from the tumour after the treatment has been provided
to the subject, for one or more proteins selected from any one or more of Tables C-F;
and
- comparing the results of the assay carried out before the treatment with the results
of the assay carried out after the treatment;
wherein the scaffold is a cell-free scaffold and the tumour is a breast cancer tumour.
[0012] In a further aspect the invention provides a cancer treatment for use in treating
a human subject with a tumour, wherein said cancer treatment has been determined as
suitable for or effective in the subject by a method according to any of second, third,
fourth, sixth or seventh aspects.
[0013] The invention is further set out in the present claims.
[0014] Except for where the context requires otherwise, references to the methods of the
invention may be taken as encompassing methods of any of the aspects herein. Embodiments
disclosed in respect of one method or use should also be taken as applicable to the
other methods or uses of the invention, unless incompatible, or otherwise stated.
Brief description of the Figures
[0015]
Figure 1 - A workflow in tumour scaffold production.
Figure 2 - Mass spectrometry analyses of 17 breast cancer tumour scaffolds and identified
proteins as well as clustering illustrated by partial component analysis (PCA) and
a heatmap.
Figure 3 - Top 21 proteins identified by dynamic PCA (p-value separation) discriminating
the unsupervised clusters illustrated by PCA and a heatmap. Tumour grade (grad) and
proliferation (Ki67) is included in the PCA and heatmap (shown by dotted circle).
Figure 4 - Top 23 proteins identified by dynamic PCA (p-value separation) discriminating
high grade breast cancer (large squares) from lower grade (small squares) and illustration
by PCA. The separation of the unsupervised clusters (circles and crosses) using the
identified proteins is also shown.
Figure 5 - PCA of the 23 proteins identified by mass spectrometry of cell-free scaffolds
significantly linked to tumour grade or proliferation. High grade breast cancer (larger
squares) and lower grade (smaller squares). The location of Ki67 and grade is indicated
by an arrow in the loading PCA plot.
Figure 6 - . Immunohistochemical Ki67 staining of a (A) peripheral part of a scaffold
culture of MDA231 cells and a (B) central part of the scaffold.
Figure 7 - Bulk qPCR of MCF7 breast cancer cells in (reading left to right): control
(2D), and three weeks of scaffolds cultures (56, 88, 94).
Figure 8 - Surrogate methods to assess the cancer initiating potential of different
breast cancer cell lines grown under regular 2D conditions (2D) or in scaffolds (3D).
Figure 9 - Tumour take in immunocompromised mice using MDA 231 breast cancer cells
(231) grown under regular 2D conditions (2D) or in two different scaffolds, 1224 and
1228 (3D).
Figure 10 - Single cell PCR of two scaffolds samples (grey) and a 2D control (dark)
using selected genes involved in cell cycle control, differentiation, cancer stem
cell and EMT regulation. In total, more than 250 separate cells were analysed and
presented as PC1 and PC3 for the different cells and the corresponding gene loading.
Figure 11 - Western blot analyses of Sox2 protein content in 2D and scaffold cultures
(#946, #978) using three different breast cancer cell lines.
Figure 12 - Time course of induced qPCR changes in MCF7 cells grown in 2D and three
different scaffolds (mean expression). Bars left to right show results for: MCF-7
2D; MCF7-3D 1 day; MCF7-3D 2 days; MCF7-3D 3 days; MCF7-3D 7 days; MCF7-3D 14 days;
and MCF7-3D 21 days.
Figure 13 - Next generation RNA-sequencing (NGS) analyses of 2D, scaffold and xenograft
samples of MCF7 cells and illustration of selected genes involved in cancer stem cell
and EMT regulation.
Figure 14 - Next generation RNA-sequencing (NGS), whole transcriptome analyses of
2D, scaffold and xenograft samples (immunocompromised mice) of the two breast cancer
cell lines MCF7 and MDA 231.
Figure 15 - NGS of 2D, scaffolds and xenografts samples and comparisons of similarities
in expression between scaffolds and xenografts cultures in relation to 2D
Figure 16 - Venn diagram illustration of NGS data and mutually regulated genes between
the three growth conditions.
Figure 17 - Identification of enriched processes in the various culture conditions
based on NGS analyses of MCF7cells.
Figure 18 - Gene set enrichment analyses (GSEA) indicating the overlap for the top
hundred reactomes enriched for among scaffold proteins as well as for upregulated
genes in MCF7 and MDA231 breast cancer cells based on NGS analyses of scaffold cultures
in comparison with 2D growth.
Figure 19 - PCA illustrations of qPCR analyses of T47D cells grown in 19 different
scaffolds indicating a spread of the different scaffold samples (A) and the influence
of the various genes analysed (B).
Figure 20 - Schematic principle and illustration of scaffolds as a clinical test of
the tumour promoting effect of the specific cancer patients scaffolds measured by
changes in gene expression of MCF7 cells.
Figure 21 - PCA illustrations of qPCR analyses of MCF7 cells grown in 46 different
scaffolds (dark) and six 2D controls (grey) (A) and the influence of the genes analysed
(B).
Figure 22 - PCA illustrations of qPCR analyses of MCF7 cells grown in 46 different
scaffolds with indication of scaffolds from patients with disease recurrences (grey)
(A) and the influence and clustering of genes analysed (B).
Figure 23 - Kaplan Meier plot of breast cancer recurrences in relation to SLUG expression
(cut-off median) in MCF7 cells grown in the different cancer scaffolds obtained from
patients (n=46) included in the study (A) and Cox multivariate analyses (B).
Figure 24 - Kaplan Meier plot of breast cancer recurrences in relation to VIMENTIN
expression (cutoff median) in MCF7 cells grown in the different cancer scaffolds obtained
from patients (n=46) included in the study (A) and Cox multivariate analyses (B).
Description of the sequences
[0016]
SEQ ID NO: 1- an adapter-ligated oligo-dT 5'-AAGCAGTGGTATCAACGCAGAGTACT30VN-3'
SEQ ID NO: 2 - template switching oligo 5'-AAGCAGTGGTATCAACGCAGAGTACATrGrG+G-3' with
rG = riboguanosine and +G = locked nucleic acid modified guanosine
SEQ ID NO 3 - IS PCR primer 5'-AAGCAGTGGTATCAACGCAGAGT-3'
Detailed description of the invention
[0017] The invention herein is concerned with new tests which can be used to characterise
tumours, especially breast cancer tumours, based on the composition and properties
of cell-free scaffolds obtained from the tumours.
[0018] The present inventors have surprisingly found that cell-free scaffold isolated from
a primary breast cancer tumour can act as a diagnostic and prognostic tool in determining
clinically relevant properties of the tumour.
[0020] The present inventors have developed a cell culture platform using cell-free scaffold
from tumours, such as primary breast cancer tumours, infiltrated with cancer cells,
which mimics in vivo growth conditions.
[0021] The complexity of
in vivo tumour growth is in strict contrast to most model systems used in cancer research
today. The
in vitro models used are represented by cell cultures of cancer cell lines growing on plastics
under high oxygen supply and immense growth factor activation. The
in vivo animal models, using mainly immunocompromised mice, at least in part create more
in vivo like cancer growth conditions by the use of implanted human tumours in the form of
xenografts. Compared with the
in vitro models, such
in vivo model systems can be used for drug testing and studies of cancer growth in a more
complex environment, but they have several limitations associated with immunocompromised
mice as well as non-human stromal reactions. In particular, breast cancer cell growth
in xenografts does not mimic
in vivo growth in patients as the cells tend to be less infiltrative and also to have large
central necrotic areas due to rapid cell division in relation to angiogenic support.
This creates an artificial cancer growth system that might be superior to less complex
cell cultures but is still not close enough to real
in vivo conditions.
[0022] In contrast to these animal models, the cell-free scaffold based culture system developed
by the inventors mimics in vivo growth conditions. The inventors have shown that a
series of changes are induced in the cancer cells cultured in the scaffold, including
changes in differentiation, in epithelial-mesenchymal transition (EMT) (a process
by which epithelial cells de-differentiate to become mesenchymal stem cells) and in
proliferation, with a final considerable cancer stem cell expansion in the cell population.
The inventors have further found that scaffolds from different patients vary in their
ability to promote cancer stem cell features, with some scaffolds inducing more EMT
features while others preserve a differentiated and proliferative phenotype in the
cancer cells. Importantly, this variation in scaffolds has been linked to clinical
properties of the original tumours from which the scaffolds were obtained. For example,
more clinically aggressive and/or recurrent tumours have scaffolds which are particularly
strong in promoting EMT features in cancer cells cultured within them.
[0023] Thus the inventors have found that cancer cells (not taken from the original source
tumour) cultured in the scaffolds can act as reporter cells, providing information
about the characteristics of the scaffold, and by extension, of the original source
tumour. By monitoring the cultured cancer cells for changes in processes such as proliferation,
differentiation, cancer stem cell-ness (pluripotency) or EMT (by testing the cells
for expression of suitable markers of these processes) it is possible to determine
properties of the original source tumour from which the scaffold was derived. These
properties can then be used in diagnosis or prognosis. It is believed that use of
patient scaffolds and reporter cells in this way has not previously been described
in the art.
[0024] The inventors have also carried out mass spectrometry analyses of scaffolds isolated
from primary breast cancer tumours to identify a number of proteins in the scaffolds.
The inventors have identified subgroups of scaffolds based on protein composition.
When the subgroups were compared with clinical characteristics of the original source
tumours, it was found that the subgrouping based on protein composition mirrored grouping
based on tumour properties such as tumour grade and tumour proliferation. Therefore
the inventors have found that protein composition of scaffold can be used to determine
clinically relevant properties of the original source tumour, and have identified
particular informative proteins.
[0025] In addition to the above, by applying a combined bioinformatics approach, to the
scaffold protein data, and next generation RNA-sequencing (NGS) data obtained from
the cancer cells cultured in the scaffolds (indicating transcriptional changes in
the cells), the inventors were able to identify an overlap between pathways in which
scaffold proteins are enriched, and up- or down- regulated genes in the cells. By
further analysis, the inventors identified scaffold proteins and associated regulated
cellular genes in three important pathways or modules, as well as key scaffold proteins
and associated regulated cellular genes representative of the most central processes.
Without wishing to be bound by theory, the inventors believe that there is a functional
link between the scaffold proteins and the regulated cellular genes in a module or
pathway. It is believed that the scaffold proteins influence gene expression in the
cells, and that this has a role in mediating the changes in cellular processes such
as proliferation, differentiation, cancer stem cell-ness (pluripotency) or EMT which
influence tumour progression. Therefore, by assaying a scaffold sample for the presence
of one or more of the identified proteins, or by assaying cancer cells cultured in
cell-free scaffold for expression of one or more of the identified genes, it is possible
to assess the influence that the scaffold has on cellular gene expression and processes,
and this in turn is informative about the clinical properties of the original source
tumour.
[0026] The diagnostic and prognostic assays developed by the inventors also find use in
selecting treatments for tumours, monitoring tumour treatments, and providing tumour
treatments as described herein.
[0027] Thus the present methods and uses allow treatments more focused on subpopulations
of cancer cells and the interplay with the microenvironment, in contrast to today's
long-standing therapy strategies employing broad and unspecific targeting of cancer
cells. The methods also provide means for monitoring how the microenvironment actually
affects cancer progression. Today, there is no such method available and novel diagnostic
tools are indeed needed.
[0028] In order to assist the understanding of the present invention, certain terms used
herein will now be further defined in the following paragraphs.
Tumour properties
[0029] The invention provides methods for determining one or more properties of a tumour.
[0030] A tumour generally refers to a swelling in a part of the body caused by an abnormal
growth of tissue. A tumour may be benign or malignant (cancerous).
[0031] A cancerous tumour may be assigned a particular grade, with higher grade indicating
a more aggressive tumour. Tumour grade is usually assigned according to the appearance
of the tumour cells, for example under a microscope. Grading systems for tumours are
known to the skilled person.
[0032] Higher grade tumours are sometimes referred to as progressive tumours. A progressive
tumour is generally more aggressive than a non-progressive tumour. Typically, a progressive
tumour has one or more of: increased invasiveness, higher malignancy grade or malignancy
potential, increased risk of recurrence, increased resistance to treatment, and/or
increased tumour proliferation, compared to a non-progressive tumour.
[0033] Tumour properties as used herein refer to any clinically relevant characteristics
of a tumour. Tumour properties may be those associated with, or indicative of, a progressive
tumour. Such tumour properties may be those which are significant in determining tumour
progression, for example, properties which are useful for distinguishing progressive
tumours from non-progressive tumours. Suitable tumour properties may include, for
example, invasiveness, migration, malignancy grade or malignancy potential, risk of
recurrence, resistance to treatment, and/or tumour proliferation. By assessing one
or more of these tumour properties, the present methods may be used to identify progressive
tumours (or tumours which are likely to develop into progressive tumours) and distinguish
these from non-progressive tumours. The methods may also be used to identify non-progressive
cancerous tumours or benign tumours. Thus the present methods may be used to classify
tumours according to the properties determined, for example, invasive (including likely
to become invasive) or non-invasive, recurrent (or likely to become recurrent) or
non-recurrent.
[0034] The present methods may also be used to predict likely response to treatment.
[0035] In this way, the present methods are useful both in diagnosing a tumour or class
of tumour in a subject, and also in predicting the way in which a tumour is likely
to develop in a subject in the future, i.e. in prognosis. Properties such as invasiveness
or malignancy grade may be particularly useful in diagnosis. Malignancy grade may
also be particularly useful in prognosis. It will be appreciated that other factors
may also be taken into account in making a diagnosis or prognosis. For example, diagnosis
may also take into account varying cell shapes. Prognosis may also depend on, for
example, expression of hormonal receptors, presence of lymph-node metastases, tumour
size, expression of oncogenes as HER2, patient age, or RNA expression based tests.
[0036] It will be appreciated that a benign tumour should have a less tumour-promoting scaffold.
Accordingly, it will be understood that a benign tumour will show substantially no
markers of a progressive tumour.
[0037] Progressive tumours typically require more aggressive forms of treatment than non-progressive
tumours. Distinguishing progressive tumours, or tumours that are likely to become
progressive, from non-progressive or benign tumours therefore enables clinicians to
select the most appropriate treatment for a tumour.
A subject
[0038] The methods and medical uses herein are practiced in respect of a subject having
a tumour. The subject may be one in need of determination of tumour properties, or
of a treatment for the tumour. The subject is a human. Suitably the subject may be
a female. The subject may be a patient undergoing medical care, or an individual requesting
medical care.
[0039] A suitable subject may be one in whom the tumour has been determined to be cancerous.
Suitable cancerous tumours are described herein, and include, for example breast cancer
tumour. Such a subject may be a cancer patient, in particular a breast cancer patient.
[0040] A suitable subject may be one believed to have a progressive tumour, such as a progressive
breast cancer tumour. For example, a subject may have symptoms consistent with a progressive
tumour. Alternatively, a subject may lack some or all symptoms consistent with a progressive
tumour.
[0041] Alternatively, a subject may be one believed to be at risk of developing a progressive
tumour, such as a progressive breast cancer tumour, for example, because of familial
history or genetic predisposition. It will be appreciated that a subject who may gain
benefit from the methods of treatment described herein may be one in whom tumour properties
are determined by the assessment conducted as part of the methods of the first and
fifth aspects of the invention.
A tumour
[0042] A tumour as referred to herein may be any suitable tumour. A tumour may be benign
or malignant. A tumour may be of any suitable tissue. In particular, a tumour may
be a breast tumour.
[0043] A tumour as referred to herein has a scaffold as described herein. The cells of such
a tumour typically exist in a microenvironment or niche, with which the cells interact.
For example, the tumour cells may exist in an extracellular matrix or stroma.
[0044] A suitable tumour may be a malignant tumour of a suitable cancer. Examples of suitable
cancers with solid tumours include: breast cancer, lung cancer, prostate cancer, colon
cancer, skin cancer, liver cancer, ovarian cancer, urinary bladder cancer, oesophageal
cancer, and pancreatic cancer.
[0045] Examples of suitable cancers with non-solid tumours include lymphomas and leukamaemia.
[0046] In one aspect the tumour is not a tumour of the liver, e.g. a liver cancer tumour.
In one aspect, the tumour is not a tumour of the pancreas, e.g. apancreatic cancer
tumour. A tumour may be a primary cancer tumour.
[0047] A tumour of particular interest is a breast tumour, in particular, a breast cancer
tumour, such as a ductal breast cancer tumour.
[0048] As in the present claims, in the method of the fifth aspect and the method of the
seventh aspect, the tumour is a breast cancer tumour.
[0049] A tumour, such as any of those described, may be one which is believed to be progressive,
or likely to become progressive.
[0050] A tumour from which a scaffold (e.g. a cell-free scaffold) is obtained may be referred
to herein as a "source tumour".
Scaffolds and cell-free scaffolds
[0051] The methods herein make use of a scaffold obtained from a tumour in a subject.
[0052] The extracellular matrix of a tumour generally comprises a collection of extracellular
molecules, including proteins, secreted by cells that provides structural and/or biochemical
support to the surrounding cells. The network of extracellular molecules constitutes
a 3-dimensional scaffold for cells in the tumour. Typically, the scaffold provides
a microenvironment for the tumour cells with which the cells can interact. A tumour
scaffold may comprise, for example collagen and various tumour promoting factors as
growth factor as well as inhibitors affecting tumour cell behaviours.
[0053] A cell-free scaffold generally refers to decellularised tumour tissue. Suitably,
a cell-free scaffold comprises decellularised extracellular material obtained from
the tumour, in which the original 3-dimensional structure is substantially preserved.
Suitably the bioactivity of the scaffold is substantially preserved. A cell-free scaffold
suitably allows effective attachment, migration, proliferation and 3-dimensional organisation
of cells cultures therein. Generally the decellularised scaffold is substantially
free of cells, in particular tumour cells. This may be assessed by any suitable means.
Merely by way of example, sectioning and microscopic visualisation may be used to
determine the presence of absence of nuclei which are indicative of cells, or DNA
analysis may be used. Substantially free means that cells are not detectable in the
assessments.
[0054] A sample comprising scaffold from a tumour may be prepared using methods known in
the art from,, for example, a biopsy.
[0055] A cell-free scaffold may be obtained from a tumour using suitable decellularising
methods to remove cells while preserving the basic tumour scaffold composition. Suitable
methods are known in the art, (an example is provided in
Thompson A et al, Acta Bio Material 12, 5034-5042 (2014)) and are described herein in the Examples. For example, decellularising methods
often employ a prolonged mild detergent treatment.
[0056] Merely by way of example, a decellularising method may comprise subjecting a suitable
tumour sample (for example, a suitable section taken from a tumour sample) to one
or more (e.g. 2, 3, 4 or more) detergent washes, often referred to as decellularisation
cycles. Any suitable detergent may be used, for example SDS, Triton X-100, NP40, Tween
20. After each cycle, a small tissue extract may be screened for the presence of absence
of cells, for example, by screening for nuclei. Typically, the cycles are continued
until cells are not detectable.
[0057] Decellularisation cycles may be followed by one or more washes (for example, in distilled
water or a suitable buffer) to remove cell debris. Decellularised samples may be sterilised
using a suitable sterilising agent.
[0058] In one embodiment, a method herein may additionally comprise obtaining a cell-free
scaffold from a suitable tumour sample.
Seeding of cell-free scaffolds with cancer cells and culture of cancer cells
[0059] In some of the methods herein, a cell-free scaffold derived from a tumour is recellularised
with cancer cells. The infiltrated cancer cells can then act as "reporter cells" as
changes occurring in the cells (as assessed by marker gene expression) provide information
about the malignancy inducing properties of the scaffold, and so the properties of
the source tumour.
[0061] In one aspect, cells are cultured in the scaffolds for 2-3 weeks before assay according
to the present methods.
Cancer cells
[0062] Any suitable cancer cells may be used to repopulate the scaffolds. Suitable cells
may be determined according to the tumour from which the scaffold has been obtained.
The cells may, for example, be of the same tissue type or cancer type as the tumour
from which the cell-free scaffold has been obtained. The cells may be breast cancer
cells, especially where the cell-free scaffold is from a breast cancer tumour. Cells
of a suitable cancer cell line may be used. Non-limiting examples of breast cancer
cell lines include MCF7 cells, MDA231 cells and T47D cells (available from ATCC).
[0063] The cancer cells are not cancer cells taken from the same patient tumour as the scaffold,
i.e the cancer cells are not cancer cells taken from the source tumour.
Markers of tumour progression.
[0064] In the method of the first aspect and related methods and uses, the cultured cancer
cells are assayed for the presence of target molecules indicative of the expression
of one or more genes in the cells.
[0065] In one embodiment the one or more genes may be one or more markers of tumour progression.
[0066] Tumour progression is generally believed to be associated with particular changes
in the tumour cells. For example, there may be changes in differentiation, proliferation,
EMT and/or cancer stem-cellness (pluripotency) in the tumour cells. Without wishing
to be bound by theory, it is believed that the apparent proliferative property of
progressive tumours is most likely preceded by a genuine increase or quality change
of cancer stem cells and EMT properties. An increase in for example EMT, which makes
epithelial cells become mesenchymal like, is further linked to migration and infiltrating
properties which makes the tumour more malignant with a higher chance of initiating
metastases. These changes in cancer stem cell and EMT features will affect the balance
of proliferative and differentiated cancer cells causing a decrease in differentiated
cells, and (at least initially) a decrease in proliferating cells. Markers of tumour
progression are generally molecules (typically biological molecules) which are indicative
of tumour progression. For example, such markers may be representative of one or more
cellular processes associated with progression. A marker may be indicative of any
of the cellular changes described above. Markers may comprise, for example, markers
of proliferation, markers of differentiation, markers of stem cells (pluripotency),
in particular cancer stem cells, or markers of the epithelial-mesenchymal transition
(EMT). Examples of such markers are presented in Table A.
[0067] It may be that in some cases, one or more markers of proliferation may be useful
in determining proliferative properties. Similarly, it may be that, in some cases,
one or more EMT markers may be particularly useful in determining tumour migration
or invasive properties.
[0068] Suitably, the one or more markers of tumour progression include markers for more
than one cellular process associated with progression, for example, 2, 3 or all 4
of the processes described above. Obtaining information about more than one process
can offer reliability or detail in determining tumour properties. Additionally or
alternatively, the one or more markers of tumour progression may include more than
one marker for the same process, for example, any of the cellular processes described
above.
[0069] A marker may act as an indicator of progression in any suitable way. Typically, marker
expression (for example, an increase or decrease in expression compared to a suitable
control) acts an indicator.
[0070] Any suitable markers of tumour progression may be used in the present methods. Suitable
markers are known in the art.
[0071] It may be that particular markers are particularly suitable for use in connection
with scaffolds from particular tumour types in the present methods. These can be determined
by the skilled person using appropriate control samples, and the methods described
herein.
[0072] Examples of markers of tumour progression are listed in Table A. Suitably, at least
one of the one or more tumour progression markers referred to in the method of the
first aspect is selected from these markers.
[0073] Suitably, at least one of the one or more tumour progression markers referred to
in the method of the first aspect is selected from CD44v2, SOX2, SNAIL2(SLUG), VIM,
ESR1, ERBB2(HER2), MiK67 and CCNA2.
[0074] This is particularly where the source tumour is a breast cancer tumour, in particular
ductal breast cancer tumour, for example ER(+ve) ductal breast cancer. The present
inventors have shown that differences in expression of these markers in reporter cells
cultured in cell-free tumour scaffold derived from ductal breast cancer tumours, allows
differentiation between tumour scaffolds from different patients.
[0075] At least one of the markers may be SNAIL2(SLUG) or VIM, in particular VIM. The inventors
have shown that expression of each of these markers in reporter cells cultured in
cell-free tumour scaffold is associated with breast cancer recurrence in the ductal
breast cancer tumour from which the scaffold is derived. Moreover, SLUG and VIM expression
changes were also significantly linked to recurrences using univariate analyses, and
VIM was further independently linked to disease recurrences in multi-variate analyses.
SLUG or VIM, in particular VIM, may also be particularly useful in determining malignancy
grade.
Genes in Table G
[0076] In one embodiment, the one or more genes referred to in the method of the first aspect
may be selected from the genes listed in Table G.
[0077] As described herein, the inventors have identified a number of genes in cancer cells
cultured in cell-free scaffold, which are involved in common pathways or modules with
particular scaffold proteins.
[0078] The genes identified by the inventors are listed in Table G, in Modules 1, 2 and
3 and "Highly Central". Module 1 represents "signaling" pathways, and consists of
proteins and genes associated with; signal transduction, signaling by SCF-KIT, downstream
signal transduction and signaling by VEGF, VEGFA-VEGFR2. Module 2 represents "repair
and stress" pathways and consists of proteins and genes associated with DNA Repair,
Cellular responses to stress, Cytosolic sensors of pathogen-associated DNA, Generic
Transcription Pathway and SUMOylation. Module 3 represents "DNA-replication" pathways
and includes proteins and genes associated with: Synthesis of DNA, DNA Replication,
M/G1 Transition and DNA Replication Pre-Initiation.
[0079] In Table G, lists of genes are presented for each of the cancer cell lines: MCF7
and MDA231. Genes are listed as upregulated or downregulated in these cells when the
cells are grown in the scaffolds.
[0080] It is believed that the scaffold proteins in a particular Module influence expression
of the genes in that Module, and this in turn mediates changes in the cells associated
with tumour progression. By assaying expression of one or more of these genes in the
cultured cells, it is possible to assess the effects of the scaffold on the cells,
and so determine properties of the original source tumour.
[0081] The one or more genes may be selected from any of Modules 1, 2 or 3, or from the
"Highly Central" list, or from any combination of these. In one embodiment the one
or more genes is selected from the "Highly Central" list of genes in Table G. These
are believed to be key genes, involved in initiating and mediating the changes in
cells associated with tumour progression, in particular, cancer stem cell and EMT
functions.
[0082] It will be appreciated that the one or more genes may be selected from more than
one Module or list, and/or that expression of more than one gene may be assayed. In
one instance the method may comprise assaying for expression of more than one gene
from the same Module.
[0083] The one or more genes may be selected from an MCF7 and/or MDA231 list in any Module.
Suitably, where the cultured cancer cells are MCF7 cells, the one or more genes may
be selected from an MCF7 list, and/or where the cultured cancer cells are MDA231 cells,
the one or more genes may be selected from an MDA231 list.
[0084] Where a gene is indicated to be upregulated in Table G, an assay is typically for
an increase in expression. Where a gene is indicated to be down-regulated in Table
G, an assay is typically for a decrease in expression.
[0085] It will be appreciated that any one or more the genes listed in Table G may represent
a target for cancer therapy.
Target molecules
[0086] Target molecules indicative of the expression of one or more genes are any molecules
which are representative of gene expression in the cultured cancer cells. Such target
molecules may be representative of gene expression either directly or indirectly.
By way of example, a suitable target molecule which is directly representative of
gene expression may comprise an RNA transcript. Alternatively, a suitable target molecule
may comprise a protein. For example, a suitable target molecule which is indirectly
representative of gene expression may comprise a protein encoded by the gene.
[0087] Examples of target molecules may also include lipids or carbohydrates.
[0088] It will be appreciated that the nature of the target molecule may be chosen in order
to be consistent with use in a preferred assaying system.
[0089] Target molecules may be obtained from the cultured cancer cells using methods known
to the skilled person, and appropriate to the nature of the target molecule. Typically,
cells are processed in order to provide a sample comprising the target molecules which
is suitable for use in an assay.
Scaffold protein markers
[0090] In the method of the fifth aspect, a scaffold obtained from a tumour is assayed for
one or more specified proteins. The scaffold is a cell-free scaffold and the tumour
is a breast cancer tumour.
[0091] In the method, a scaffold obtained from the tumour (a breast cancer tumour) is assayed
for one or more proteins selected from any one or more of Tables C-F.
[0092] The inventors have shown that the proteins in Table B can be used to subgroup scaffolds
in a way that mirrors clinical properties of the source tumours, such as higher or
lower grade. Therefore the proteins are useful in classifying source tumours by tumour
property.
[0093] Proteins listed in PCA Cluster 1 in Table B typically show a negative association
with tumour proliferation or tumour grade. Proteins listed in PCA Cluster 2 in Table
B typically show a positive association with tumour proliferation or tumour grade.
[0094] As used herein, where a protein is described as having a positive association with
a given tumour property, e.g. proliferation or grade, this means that an increased
amount of that protein (relative to a suitable standard) is indicative of that property.
Similarly, where a protein is described as having a negative association with a given
tumour property, e.g. high proliferation or high grade, this means that an decreased
amount of that protein (relative to a suitable standard) is indicative of that property.
[0095] In one embodiment, the method comprises assaying for one or more proteins selected
from Table C or Table D. The proteins in Table C have been identified by the inventors
as significantly linked to tumour proliferation (p≤0.05). The proteins in Table D
have been identified by the inventors as significantly linked to tumour proliferation
(p<0.01). Therefore tests based on proteins in Table C or D are particularly useful
for determining tumour proliferation properties.
[0096] In one embodiment, the method comprises assaying for one or more proteins selected
from Table E or Table F. The proteins in Table E have been identified by the inventors
as significantly linked to tumour grade (p≤0.05). The proteins in Table F have been
identified by the inventors as significantly linked to tumour grade (p<0.01). Therefore
tests based on proteins in Table E or F are particularly useful for determining tumour
proliferation properties.
[0097] In Tables C-F, proteins having a positive association with high proliferation (Tables
C & D) or high grade (Tables E & F) are denoted by a (+). Proteins having a negative
association with high proliferation (Tables C & D) or high grade (Tables E & F) are
denoted by a (-).
[0098] The scaffold proteins listed in Table G have been identified by the inventors as
interacting in pathways or modules with genes expressed in cancer cells cultured in
the scaffold. The proteins are believed to be important in influencing expression
of genes in the cells, as listed in the Table. The inventors believe that the scaffold
proteins influence expression of the genes in tumour cells in vivo, and that this
helps to mediate changes in the tumour cells that are associated with tumour progression.
The proteins in Table G are listed as in Module 1, Module 2, Module 3, or "Highly
Central" in Table G. The "Highly Central" list of scaffold proteins in Table Gare
believed to be key regulatory proteins, involved in initiating and mediating the changes
in cells associated with tumour progession, in particular, cancer stem cell and EMT
functions.
[0099] The method of the fifth aspectcomprises assaying the scaffold for one or more proteins
selected from one or more of Tables C-F. It will be appreciated therefore that the
one or more proteins may be selected from more than one of the Tables, and/or that
more than one protein may be assayed.
[0100] The method of the fifth aspect may additionally comprise assaying the scaffold for
one or more of the proteins in Table H. The inventors have identified the proteins
listed in Table H in cell-free scaffolds obtained from breast cancer tumours.
[0101] Also described herein is a method for determining one or more tumour properties in
a subject with a tumour, the method comprising:
- assaying a sample comprising scaffold obtained from the tumour for one or more proteins
selected from Table H; and
- determining one or more tumour properties in the subject based on the results of the
assay.
[0102] Unless otherwise specified or incompatible, terms, methods and uses described in
connection with the methods of the fifth aspect are also applicable to this method.
Tables of Genes and Proteins
[0103] Genes and proteins herein are identified in a number of Tables. For clarification,
the genes and proteins are also denoted in the Tables by Accession Numbers.
[0104] The genes and proteins are exemplified for a human subject.
Assaying
[0105] In the method of the first aspect, the term "assaying" refers to determining the
presence of target molecules representative of expression of one or more genes.
[0106] The determination may comprise a simple assessment of the presence or absence of
the target molecule or may include a determination of the quantity of the target molecule
present.
[0107] A suitable method by which such assaying may be carried out is selected based on
type of target molecule selected.
[0108] For example, gene expression can be measured directly by techniques that allow the
detection and quantification of RNA target molecules, such as RT-PCR, real-time PCR
(qPCR), Northern blot, RNA sequencing (RNA-seq) and RNA microarray.
[0109] In another example, gene expression can be measured indirectly, by techniques that
allow the detection and quantification of protein target molecules, such as ELISA,
radioimmunoassay, immunoprecipitation, Western blot and mass spectrometry. Other suitable
techniques for assaying proteins may be known to the person skilled in the art.
[0110] In a suitable embodiment an assay may allow multiple sets of target molecules to
be assayed within a single reaction. An assay meeting such requirements may be referred
to as a multiplex assay. Suitably a multiplex assay may allow all requisite target
molecules to be assayed within a single reaction mixture (a "single tube" multiplex
assay). Single tube multiplex assays may be particularly suitable for assaying mRNA
transcript target molecules within a sample.
[0111] Other methods suitable for assaying gene expression will be known to the person skilled
in the art.
[0112] Suitably, gene expression data obtained in the assay is compared with a suitable
standard or reference. Expression of a particular gene may be increased (up-regulated)
or decreased (downregulated) compared to the standard. In one instance, a gene may
show a statistically significant increase or decrease in expression compared to the
standard. The change in expression of the gene is indicative of a cellular process
as described herein.
[0113] A suitable standard may be, for example, gene expression in control cells, e.g. a
control cell line, (typically the same cells or cell line as the cancer cells cultured
in the cell-free scaffold) cultured under standard 2-D conditions. A number of controls
may be used and a suitable data set constructed in order to provide a suitable standard
or standards.
[0114] Another example of a suitable standard may be an expression data set for the gene,
obtained using scaffolds derived from a range of source tumours, typically tumours
of the same tissue type or cancer type as the source tumour in the test assay.
[0115] As described herein, expression may be determined for more than one gene in the present
methods, for example, for markers of more than one cellular process, and these may
each be assessed as above. In this way, a picture of a tumour, and of its properties,
may be constructed.
[0116] In the method of the fifth aspect, the term "assaying" refers to determining the
presence of one or more of the selected proteins in the scaffold. The determination
may comprise a simple assessment of the presence of absence of the protein or may
include a determination of the quantity of the protein present. Suitably the determination
comprises a determination of the quantity of the protein present.
[0117] Typically, assays are carried out on a suitable sample prepared from the scaffold.
This may be, for example, a sample of fixed tumour material.
[0118] Proteins may be assayed in the sample using any suitable technique that allows detection
and/or quantification of protein molecules. Examples include immunohistochemistry,
ELISA, radioimmunoassay, immunoprecipitation, Western blot protein ligation assays
and mass spectrometry. Suitable, mass spectrometry may be used. Quantification of
the amount of protein may be achieved by using suitable standards, e.g. a reference
cell line having a specific amount of the protein, or known amount of purified protein.
Other suitable techniques for assaying proteins may be known to the person skilled
in the art.
[0119] The amount of protein in the test scaffold sample may be compared with a suitable
database derived from clinically characterised scaffold samples.
Treatment
[0120] The determinative methods of the first and fifth aspects are also useful in selecting
tumour treatments, monitoring tumour treatments and in treating tumours. Tumour treatment
can vary depending on the grade of the tumour. A progressive tumour with, for example,
high grade and invasiveness (or a tumour which is likely to develop into such a progressive
tumour) will typically require more aggressive treatment. Therefore assessment of
tumour properties according to the present methods can be used to select appropriate
treatment. Similarly, application of the determinative assays of the first and fifth
aspects during and/or after treatment can be used to monitor the efficacy of treatment.
Cancer treatments
[0121] As used herein, "treat", "treating" or "treatment" refer to provision of a clinical
improvement in the subject as regards the tumourous condition. Typically, this refers
to a clinical improvement of cancer in a subject with a cancerous tumour. A clinical
improvement may be demonstrated by an improvement of the pathology and/or symptoms
associated with the cancer.
[0122] Clinical improvement of the pathology may be demonstrated by one or more of the following:
increased time to regrowth of cancer upon stopping of treatment, lack of regrowth
of cancer upon stopping treatment, decreased tumour invasiveness, reduction of metastasis,
increased cancer cell differentiation, or increased survival rate. Effective treatment
may be demonstrated by the establishment, and optionally maintenance, of at least
one of these indications.
[0123] A clinical improvement may be demonstrated by one or more anti-tumour effects. Non-limiting
examples of anti-tumour effects include inhibition of tumour growth, delay in tumour
growth, reduced speed of tumour growth, or a partial or complete reduction in tumour
mass.
[0124] Clinical improvement of symptoms associated with cancer may be, but are not limited
to partial or complete alleviation of pain and/or swelling, increased appetite, reduced
weight loss and reduced fatigue.
[0125] It will be appreciated that a clinical improvement may also be determined as an improvement
in tumour properties as assessed using the methods herein.
[0126] Treatments for cancerous tumours, are known to the skilled person, and include, for
example, chemotherapy, endocrine therapy, radiotherapy, immunotherapy or surgical
options.
[0127] Treatments may vary according to the tissue that the tumour occurs in, and according
to the grade of the tumour. More aggressive tumours will typically require more aggressive
treatment, for example, more aggressive drugs, higher doses of drugs or radiation,
or surgical intervention.
[0128] Non-limiting examples of therapies for breast cancer are listed in the Table below,
together with approximate treatment concentration ranges for human breast cancer.
|
Treatment name |
Treatment concentration for human |
Chemotherapy |
Epirubicin (Anthracyclin) |
60-90 mg/m2 |
Cyclophosphamide |
500-600mg/m2 |
5-FU (5-fluorouracil) |
500-600mg/m2 |
Paclitaxel (Taxanes) |
70-90 mg/m2 |
Eribulin |
- |
Vinorelbin |
- |
Methotrexate |
- |
Endocrine therapy |
Tamoxifen |
20mg/day |
Fulvestrant |
500mg/month |
Other therapies |
Trastuzumab |
- |
Pertuzumab |
- |
Lapatinib (HER2) |
- |
Everolimus (mTOR) |
- |
Selecting, providing and monitoring treatment
[0129] As described herein, the determinative methods of the first and fifth aspects are
useful in determining a suitable treatment for a subject with a tumour. Once tumour
properties have been determined, a treatment may be selected which is appropriate
to those particular properties of the tumour. For example, a high grade, invasive
tumour (or a tumour which is likely to develop into a high grade invasive tumour)
will typically require a more aggressive form of treatment.
[0130] In second and sixth aspects, the invention provides a method for determining a suitable
treatment for a subject with a tumour, comprising determining tumour properties in
the subject by a method according to the first or fifth aspect, and determining a
suitable treatment based on the tumour properties.
[0131] The determinative methods of the first and fifth aspects are also useful for determining
or monitoring efficacy of treatment in a subject with a tumour. Typically, this is
done by performing the assays of the determinative methods before and after treatment,
and comparing the assay results.
[0132] Thus in a third aspect, the invention provides a method for determining or monitoring
efficacy of treatment for a human subject with a tumour, the method comprising:
- (a):
- seeding a cell-free scaffold, obtained from the tumour (the source tumour) before
the treatment has been provided to the subject, with cancer cells;
- culturing the cancer cells in the scaffold; and
- assaying the cultured cancer cells for the presence of target molecules indicative
of the expression of one or more genes in the cells;
- (b):
- seeding a cell-free scaffold, obtained from the tumour (the source tumour) after the
treatment has been provided to the subject, with cancer cells;
- culturing the cancer cells in the scaffold;
- assaying the cultured cancer cells for the presence of target molecules indicative
of the expression of one or more genes in the cells;
and
- (c) comparing the results of the assays in (a) and (b);
wherein the cancer cells are not cancer cells taken from the source tumour in the
subject.
[0133] In one embodiment the one or more genes may be one or more markers of tumour progression.
In one embodiment the one or more genes may be selected from Table G.
[0134] Step (c) may comprise comparing the expression of one or more genes determined in
step (a) with the expression of one or more genes determined in step (b).
[0135] In one embodiment, at least one of the one or more genes in steps (a) and (b) may
be the same in each step. Thus the method may comprise comparing the expression of
the same particular gene before and after treatment.
[0136] In one embodiment, at least one of the genes in step (a) and at least one of the
genes in step (b) are markers of the same cellular process or change. For example,
each may be markers of proliferation, or markers of differentiation, or markers of
stem cells (pluripotency), in particular cancer stem cells, or markers of the epithelial-mesenchymal
transition (EMT).
[0137] The target molecules which are assayed in steps (a) and (b) may be the same type
of target molecule or may be different.
[0138] It will be appreciated that description provided herein in connection with the method
of the first aspect, will also be applicable to the method of the third aspect. Thus,
for example, description of genes in connection with the first aspect are also applicable.
[0139] In a seventh aspect, the invention provides a method for determining or monitoring
efficacy of a treatment for a human subject with a tumour, the method comprising:
- (a) assaying a scaffold, obtained from the tumour before the treatment of the subject,
for one or more proteins selected from any one of more of Tables C-F;
- (b) assaying a scaffold, obtained from the tumour after the treatment of the subject,
for one or more proteins selected from any one or more of Tables C-F; and
- (c) comparing the results of the assay carried out before the treatment with the results
of the assay carried out after the treatment;
wherein the scaffold is a cell-free scaffold and the tumour is a breast cancer tumour.
[0140] Step (c) may comprise comparing the presence or amount of one or more proteins determined
in step (a) with the presence or amount of one or more proteins determined in step
(b).
[0141] It will be appreciated that description provided herein in connection with the method
of the fifth aspect, will also be applicable to the method of the seventh aspect.
Thus, for example, description of proteins in connection with the fifth aspect are
also applicable.
[0142] In the methods of the third and seventh aspects, steps (a) and (b) may additionally
comprise determining one or more tumour properties based on the assay results. In
that case, the method for determining or monitoring efficacy of treatment may comprise
comparing one or more tumour properties before and after treatment.
[0143] It will be appreciated that the treatment which is being assessed may be a complete
course of treatment, or a partial treatment or a particular stage of treatment. Thus,
in one embodiment, step (a) may be carried out before any treatment has been provided
to the subject, and step (b) may be carried out after completion of a course of treatment.
In another embodiment, step (a) may be carried out before any treatment has been provided
to the subject, and step (b) may be carried out after a partial treatment, or after
a particular stage of treatment. In another embodiment, step (a) may be carried out
during treatment, and step (b) may be carried out at a later stage of treatment. Step
(a) and/or step (b) may be repeated as treatment progresses. In this way, the method
can be used to provide an ongoing assessment of treatment.
[0144] Efficacy of treatment will be shown by a detectable improvement in one or more tumour
properties after treatment. This may be determined by a change in marker gene expression
which is indicative of such an improvement. An improvement in tumour properties generally
refers to a reduction in one or more properties associated with progression, such
as any of those described herein. For example, an improvement may be a reduction in
invasiveness, migration, malignancy grade, malignancy potential recurrence, resistance
to treatment and/or proliferation.
Providing treatment and medical uses
[0145] In some instances, the methods of the first and fifth aspects include an additional
step of selecting a suitable treatment. The treatment will be selected according to
the tumour properties determined. Also described herein is a method of the first or
fifth aspects which includes an additional step of providing a suitable treatment
to the subject.
[0146] In a further aspect, the invention provides a cancer treatment for use in treating
a subject with a tumour. Also described herein is a method of treating subject with
a tumour.
Providing
[0147] The term "providing" as used herein encompasses any techniques by which the subject
receives a particular therapy. Suitable techniques for administering cancer therapies
are known to the skilled person.
Predicting likely efficacy of treatment
[0148] A method according to the first aspect may also be used to assess the likely efficacy
of a particular treatment in a subject with a tumour. By applying the treatment to
the cell-free scaffold comprising the cultured cells, and assessing the effect on
the outcome of the determinative assay, it is possible to predict the likely efficacy
of the treatment in the source tumour.
[0149] Thus, in a fourth aspect, the invention provides a method for determining likely
efficacy of a treatment for a human subject with a tumour, the method comprising:
- (a)
- seeding a cell-free scaffold obtained from the tumour (the source tumour) with cancer
cells;
- culturing the cancer cells in the scaffold;
- assaying the cultured cancer cells for the presence of target molecules indicative
of the expression of one or more genes in the cells;
- (b) applying the treatment to the scaffold comprising the cancer cells;
- (c) assaying the cultured cancer cells after the treatment has been applied, for the
presence of target molecules indicative of the expression of one or more genes in
the cells;
and
- (d) comparing the results of the assays in (a) and (c);
wherein the cancer cells in (a)-(c) are not cancer cells taken from the source tumour
in the subject.
[0150] In one embodiment the one or more genes may be one or more markers of tumour progression.
In one embodiment the one or more genes may be selected from Table G.
[0151] Step (d) may comprise comparing the expression of one or more genes determined in
step (a) with the expression of one or more genes determined in step (c).
[0152] In one embodiment, at least one of the one or more genes in steps (a) and (c) may
be the same in each step. Thus the method may comprise comparing the expression of
the same particular gene before and after treatment.
[0153] In one embodiment, at least one of the genes in step (a) and at least one of the
genes in step (c) are markers of the same cellular change or process. For example,
each may be markers of proliferation, or markers of differentiation, or markers of
stem cells (pluripotency), in particular cancer stem cells, or markers of the epithelial-mesenchymal
transition (EMT).
[0154] The target molecules which are assayed in steps (a) and (c) may be the same type
of target molecule or may be different.
[0155] Steps (a) and (c) may additionally comprise diagnosing or prognosing one or more
tumour properties based on the assay results. In that case, the method for determining
likely efficacy of treatment may comprise comparing one or more tumour properties
before and after treatment.
[0156] Efficacy of treatment will be shown by a detectable improvement in one or more tumour
properties after treatment. This may be determined by a change in marker gene expression
which is indicative of such an improvement.
[0157] It will be appreciated that description provided herein in connection with the method
of the first aspect, will also be applicable to the method of the fourth aspect. Thus,
for example, description of genes in connection with the first aspect are also applicable.
Other terms
[0158] Throughout the description and claims of this specification, the singular encompasses
the plural unless the context otherwise requires. In particular, where the indefinite
article is used, the specification is to be understood as contemplating plurality
as well as singularity, unless the context requires otherwise.
[0159] Features, integers, characteristics, compounds, chemical moieties or groups described
in conjunction with a particular aspect, embodiment or example of the invention are
to be understood to be applicable to any other aspect, embodiment or example described
herein unless incompatible therewith.
[0160] Throughout the description and claims of this specification, the words "comprise"
and "contain" and variations of the words, for example "comprising" and "comprises",
mean "including but not limited to", and are not intended to (and do not) exclude
other moieties, additives, components, integers or steps. However, it will be appreciated
that the words "comprise" and "contain" encompass within their meaning, the terms
"consisting of" and "consisting essentially of".
[0161] Unless otherwise noted, technical terms are used according to conventional usage.
Definitions of common terms in molecular biology may be found in
Benjamin Lewin, Genes V, published by Oxford University Press, 1994 (ISBN 0-19- 854287-9);
Kendrew et al. (eds.), The Encyclopedia of Molecular Biology, published by Blackwell
Science Ltd., 1994 (ISBN 0-632-02182-9); and
Robert A. Meyers (ed. ), Molecular Biology and Biotechnology: a Comprehensive Desk
Reference, published by VCH Publishers, Inc., 1995 (ISBN 1-56081-569-8).
[0162] All publications, patents and patent applications mentioned in this specification
are herein incorporated by reference in to the specification to the same extent as
if each individual publication, patent or patent application was specifically and
individually indicated to be incorporated herein by reference. Unless stated otherwise,
the contents of any Internet sites referenced herein are incorporated herein by reference
as of 3 November 2016.
[0163] Any references to "detectable" or "detected" are as within the limits of detection
of the given assay or detection method.
EXAMPLES
[0164] The invention will now be described by way of specific Examples and with reference
to the accompanying Figures, which are provided for illustrative purposes only and
are not to be construed as limiting upon the teachings herein.
Materials and methods
Decellularization procedure
[0165] Breast cancer samples were collected directly after surgery or from a frozen biobank
via the clinical pathology diagnostic unit at Sahlgrenska University Hospital. A piece
of the tumor containing area, approximately 3x3x2 mm, was sectioned from the sample.
The sample sizes varied depending on the available tumour material but the maximum
thickness of the scaffolds used for the process did not exceed 3 mm. Tumour pieces
then underwent repetitive washes consisting of incubation in 0.1% SDS + 0.02 % Na-Azide
(VWR-786-299) + 5mM 2H
2O-Na
2- EDTA (Sigma-ED2SS) and 0.4 mM PMSF (Sigma -93482) for 6 hours followed by rinses
in destilled water including (0.02 % Na-Azide and 5mM 2H
2O-Na
2- EDTA and 0.4 mM PMSF) for 15 min (1). After each decelluralization cycle a small
piece of tissue was screened for the presence of nuclei using standard histological
procedures and if nuclei were still present, the wash cycle was repeated. The number
of washes needed varied from 1-4 (mean 1,9). Two wash cycles were sufficient for more
than 80% of the samples. After successful decellularization, the specimens were washed
for 72 hrs in distilled water exchanged every 12 hour to remove cell debris followed
by a 24 hour wash in PBS (Medicago 09-9400-100). All wash steps were performed at
37°C on an agitator with gentle shaking (175 RPM). Sterilization was performed by
incubation in 0.1% peracetic acid (Sigma Aldrich 433241) in destilled water for 1
hour in room temperature followed by a wash in PBS containing 1% Antibiotic-Antimycotic
(Gibco 15240096) for 24 hours 37°C (175 RPM). Scaffolds were then stored up to 1 month
in PBS containing 0.02 % Na-Azide and 5mM 2H
2O-Na
2- EDTA in +4°C. Before recellularization, scaffolds were washed in PBS containing
1% Antibiotic-Antimycotic for 24 hours, 37°C or soaked in complete media for 1 h to
remove storage buffer.
Recellularization with breast cancer cells
[0166] Different methods to recellularize scaffolds were tested including variations in
cell amounts, culture conditions and application of cells. The optimal method to obtain
successful recullarization was to use 3x3 mm scaffolds with a maximum depth of 2 mm
and adding 3 × 10
5 cells to a 48-well plate containing 0,5 ml cell line specific media with 1% Antibiotic-Antimycotic.
The day after seeding cells, scaffolds were transferred to a new well and visually
checked every fourth day. If cells were growing outside the scaffold area the scaffold
was transferred to a new well. Optimal growth time for the scaffolds was 2-3 weeks.
FACS
[0167] Individual cells were collected by FACS in a 96-well plate and subjected to direct
cell lysis in RNase free water with BSA (Thermo Scientific B14) 1 mg/ml, and immediately
frozen on dry ice. To each 96-well plate, 100 cells were sorted to two wells (positive
control) and two wells were empty (negative control).
Harvest and extraction of RNA
[0168] Recellularized scaffolds were washed twice in PBS before lysed in lysis buffer (RNase
free water with BSA (Thermo Scientific B14) 1 mg/ml). RNA Spike II (TATAA RS10SII)
5 ul/100ul and RnaseOUT (Invitrogen 10777-019) 4U/ul was also added in the lysis step
in material derived from the biobank. Control cells grown in monolayer was either
washed with PBS and frozen immediately on dry ice or scraped off the plastic surface
and harvested using lysis buffer or QIAzol. RNA was then extracted or samples were
placed on dry ice and stored in -80°C.
[0169] To retrieve RNA, samples were thawed on ice and homogenized using a stainless steel
bead (Qiagen 69989) in TissueLyzer II (Qiagen) for 2x5min, 25Hrz. To the frozen tumour
pieces QIAzol and a steel bead was added prior to homogenization. Samples were visually
checked and if not shattered, homogenization was repeated for another 5 minutes.
[0170] Samples were centrifuged 4°C 1min at 10000rpm and used for cDNA synthesis or RNA
was further purified by phenol chloroform extraction, miRNeasy Mini Kit (Qiagen 217084)
and DNased by Rnase-Free Dnase Set (Qiagen 79254). RNA concentration was measured
by NanoDrop and samples for QuantSeq sequencing was quality tested on Bioanalyzer.
Reverse transcription
[0171] cDNA synthesis from RNA was carried out using GrandScript cDNA synthesis kit (TATAA
Biocenter). Reverse transcription was performed in 10-20 µl reaction mixes and was
performed at 22-25°C for 5min, 42°C for 30min and terminated by heating to 85°C for
5min followed by cooling down to 4°C. All samples were diluted 4x with water before
further processing.
Preamplification
[0172] For single cell analysis preamplification was performed on cDNA (corresponding to
half a cell) with SYBR GrandMaster Mix (TATAA Biocenter) using a primer pool of 96
primer pairs. Preamplification was performed in 40 µl containing SYBR GrandMaster
Mix (1x), primers (40 nM, each primer) and BSA (1 µg/µl). Preamplification was performed
at 95°C for 3min followed by 20 cycles of amplification (95°C for 20sec, 60°C for
3min and 72°C for 20sec) and a final incubation at 72°C for 10 min. All preamplified
samples were chilled on ice and diluted 1:20 in TE-buffer, pH 8.0 (Ambion).
qPCR
[0173] All qPCR primers were designed using Primer3 (http://frodo.wi.mit.edu/primer3/input.htm),
Primer-BLAST
(http://www.ncbi.nlm.nih.gov/tools/primer-blast/) or Netprimer (Premier) and synthesized by Sigma-Aldrich. Primers were controlled
for specificity using BLAST (NCBI). Primer pairs were tested in qPCR runs for their
specificity and PCR product sizes were confirmed by gel electrophoresis.
[0174] qPCR was performed on 2 µl diluted, preamplified cDNA or non-preamplified cDNA using
SYBR GrandMaster Mix (TATAA). qPCR was performed in 6 µl containing SYBR GrandMaster
Mix (1x) and primers (400 nM, each primer) in 384-well plates (FrameStar 480, 4titude)
on a CFX384 Touch Real-Time PCR Detection System (Bio-Rad). qPCR samples were heated
to 95°C for 2 min and amplified for 35-50 cycles at 95°C for 5 s, 60°C for 20 s, and
70°C for 20 s followed by a melting curve analysis performed from 65°C to 95°C with
0.5°C per 5 s increments.
Data analysis
[0175] Cq values were determined by the second derivative maximum method using the CFX Manager
Software version 3.1 (Bio-Rad). Data pre-processing were performed with GenEx (MultiD)
as described (2). Briefly, samples with aberrant melting curves were removed. For
single cell analysis, an inter-plate calibrator (IPC) sample was included in the qPCR
used for normalization. Cycle of quantification values larger than 28 were replaced
with 28. Data were transformed to relative quantities assuming that a cycle of quantification
value of 28 was equal to one molecule. Missing data were replaced with 0.5 molecules.
For bulk-qPCR samples values were normalized using 2D control samples and cycle of
quantification values larger than 35 were replaced with 35. Data were transformed
to relative quantities assuming that a cycle of quantification value of 35 was equal
to one molecule. Missing data were replaced with 36 molecules.
Whole-mRNA reverse transcription and pre-amplification
[0176] RNA from cells grown in monolayer, scaffolds or xenografts was diluted in a buffer
containing 5 µl, 1µg/µl BSA, 2.5% glycerol (Fisher Scientific) and 0.2% Triton X-100
(Sigma-Aldrich-Aldrich) in DNase/RNase-free water (Life Technologies) to reach a final
amount of 10 ng total RNA in 5µl sample volume. Samples were processed according to
a recently published Smart-Seq2 protocol (3) with minor changes (NB: final concentrations
of the hybridization and reverse transcription (RT) protocol are given in brackets
and refer to RT reaction volume). In short, adapter-ligated oligo-dT (1 µM, 5'-AAGCAGTGGTATCAACGCAGAGTACT
30VN-3', with V = A, C or G and N = A, C, G, or T, Sigma-Aldrich) were hybridized to
mRNA in the presence of dNTP (1 mM, Sigma-Aldrich) and ERCC spike-in controls (3)(corresponding
to 1 µl of 1:5000 diluted stock solution; Life Technologies) at 72°C for 3 min. RT
was performed in 15 µl containing SuperScript II first-strand buffer (1x; 50 mM Tris-HCI,
pH 8.3, 75 mM KCI, and 3 mM MgCl
2, Invitrogen), betaine (1 M, Sigma-Aldrich), DTT (5 mM), additional MgCl
2 (10 mM, both Life Technologies), template switching oligo (TSO; 5'-AAGCAGTGGTATCAACGCAGAGTACATrGrG+G-3'
with rG = riboguanosine and +G = locked nucleic acid modified guanosine; 0.6 µM, Eurogentec),
RNaseOUT (15 U, Invitrogen), and SuperScript II enzyme (150 U, Invitrogen) at 42°C
for 90 min and 70°C for 15 min before being chilled to 4°C. Aliquots of non-amplified
cDNA samples were stored at -20°C until further use.
[0177] Preamplification of 7.5 µl cDNA was performed in 50 µl containing KAPA Hifi HotStart
Ready Mix (1x; KAPA Biosystems) and IS PCR primer (60 nM, 5'-AAGCAGTGGTATCAACGCAGAGT-3',
Sigma-Aldrich) as follows: denaturation at 98°C for 3 min followed by 24 cycles of
incubation at 98°C for 20 s, 67°C for 15 s, and 72°C for 6 min, and a final incubation
at 72°C for 5 min before being chilled to 4°C.
[0178] Aliquots of 1 µl purified samples were forwarded to capillary gel electrophoresis
using the High Sensitivity DNA Kit (Agilent) on a 2100 Bioanalyzer (Agilent) to assess
their concentration and product length distribution.
Preparing indexed RNA-sequencing libraries
[0179] RNA-sequencing libraries were generated using the Nextera XT DNA Sample Preparation
and Index kits (Illumina) according to the manufacturer's recommendations with minor
changes. In short, 0.1 ng of preamplified cDNA were tagmented in a volume of 20 µl
containing 10 µl TD buffer and 5 µl ATM at 55°C for 5 min. Tagmentation was stopped
by addition of 5 µl of NT buffer and incubation at room temperature for another 5
min (all solutions supplied in the Nextera XT DNA Sample Preparation Kit). For introducing
indexing sequences, 15 µl NMP PCR master mix solution (Nextera XT DNA Sample Preparation
Kit) and 5 µl of i5 and i7 index primers, each, (Nextera XT v2 Index Kit) were added
to tagmented samples and subjected to amplification. Therefore, samples were heated
to 72°C for 3 min, denaturated at 95°C for 30 s and amplified for 16 cycles at 95°C
for 10 s, 55°C for 30 s, and 72°C for 30 s, followed by a final extension step at
72°C for another 5 min before being chilled to 10°C. Samples were purified using the
AMPure XP beads kit (Agencourt, Beckman Coulter) as recommended by the manufacturer
with minor changes. In short, tagmented and indexed cDNA was bound to beads (sample:beads
volume ratio of 0.6) at room temperature for 5 min and separated from supernatant
on a magnetic stand (DynaMag 96 Side, Life Technologies) for another 5 min. Supernatants
were removed and captured cDNA-charged beads were rinsed twice with 200 µl 80% ethanol
for 30 s before being air dried for approximately 2 min. Purified cDNA was recovered
from beads in DNase/RNase-free water yielding 15 µl eluate and stored at -20°C until
further use.
[0180] Mean fragment length (High Sensitivity DNA Kit) and concentration (dsDNA High Sensitivity
Assay Kit, Qubit, Life Technology) of indexed single-cell libraries were assessed.
Single-cell libraries diluted to 15 nM and pooled. Quality and concentration of the
final pool was assessed as above and it was diluted to 10 nM before being forwarded
to sequencing.
RNA sequencing
[0181] Sample pool was forwarded to paired-end sequencing on a high-throughput sequencer
(NextSeq 500, Illumina).
Accompanying quality controls and measurements
[0182] Quality control singleplex qPCR on cDNA using RPS10 was performed where 1 µl undiluted,
non-preamplified cDNA were run in 10 µl containing 1x TATAA SYBR GrandMaster Mix and
400 nM of each primer in 384-well plates (FrameStar 480, 4titude) on a CFX384 Touch
Real-Time PCR Detection System (Bio-Rad). qPCR samples were heated to 95°C for 2 min
and amplified for 50 cycles at 95°C for 5 s, 60°C for 20 s, and 70°C for 20 s followed
by a melting curve analysis performed from 65°C to 95°C with 0.5°C per 5 s increments.
Cq values were determined by the second derivative maximum method using the CFX Manager
Software version 3.1 (Bio-Rad). Additionally, a similar qPCR analysis was performed
on preamplified samples to make sure there was no inconsistency in the preamplification
reaction.
Alignment and gene level expression estimation
[0183] Reads were aligned to the hg19 reference of the human genome, with ERCC spike-in
sequences appended, using the STAR (5) read mapper with splice junctions supplied
from the GENCODE (6) V17 annotation. To obtain expression estimates, reads were binned
to genes using HTseq (7), with the options "-s no" and "-m intersection-strict". Read
counts thus derived were then normalized using sample library size to obtain RPM values.
Principal component analysis
[0184] A principal component analysis was performed using MATLAB function pea or GenEx (Multid).
The analysis was performed on zscore transformed expression values as standardized
log
2(RPM+1).
Differential expression analysis
[0185] Differential expression analysis was performed in R using the DESeq2 analysis method
(7). Samples from the two cell lines MCF7 and MDA-MB-231 were analyzed separately
and within each cell line samples were grouped as 2D, scaffold or xenograft. A pre-filtering
step was performed removing genes with a sum of reads of zero or one. Differentially
expressed genes were defined pair-wise between all conditions using a cutoff of padj
of 0.05. Up-regulated and down-regulated genes were further defined using a cutoff
of log2(fold change) of 1 and -1, respectively.
Gene set enrichment analysis
[0186] The differentially expressed genes were further analysed using gene set enrichment
analysis where the Reactome gene set was used to find pathways connected to the different
gene lists.
Xenografts
[0187] Cell lines MDA-231, MCF7 and T47D were grown on scaffolds and in 2D cultures. Accutase
(Sigma Aldrich A6964) was used for dissociation into single cell suspensions. Cells
were counted manually and suspended in DMEM mixed 1:1 with GF reduced Matrigel (BD
Biosciences) prior to injections subcutaneously in the flanks of NOG mice (immunocompromised,
non-obese severe combined immune deficient interleukin-2 chain receptor γ knockout
mice) from Taconic, Denmark. A 17β-Estradiol pellet, 90-day release (Innovative Research
of America) was implanted 2-4 days before cell injections in the mice receiving an
estrogen dependent cell line. Tumors were measured using calipers twice a week and
tumour volume was calculated by the formula 1/2(Length × Width
2).
Western blot
[0188] Cells were harvested in RIPA buffer containing protease inhibitors and EDTA, pipetted
up and down occasionally while incubated on ice for 30 min to 1 h. Lysates were centrifuged
at 8,000XG for 15 min, 4°C. Supernatant was transferred to a new tube and used for
western blot analyses. Lysates were mixed with loading buffer, reducing agents and
heated to 98°C for 5 min and then allowed to cool. Standard procedures for BioRad
western blot system was used. Proteins were transferred to a Nitrocellulose membrane
using wet transfer system 200 mA.
Mammosphere Assay
[0189] Mammosphere assays were carried out as described in (9)
Protein quantification and proteomic analysis (TMT)
[0190] For proteomics analysis the TMT-labeled relative quantification LC-MSMS method was
used. Equal amounts of proteins (30 ug samples) were homogenized and extracted from
each scaffold by a lysis buffer (M urea, 4% 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate
(w/v), 0.2% sodium dodecyl sulfate (SDS) (w/v), 5 mM ethylenediaminetetraacetic acid).
For relative quantification, the proteins were trypsinized into peptides and further
labeled with tandem mass tags (TMTs) with a unique tag for each sample and the reference.
The peptides were fractionated by a strong cation exchange chromatography (SCX) and
the separation for the mass-to-charge (m/z) ratio of the peptides (MS) the reversed-phase
nanoLC interfaced QExactive was used followed by fragmentation (MS/MS) for peptide
sequence information and relative quantification to an Orbitrap Tribrid Fusion MS
instrument. Stepped HCD fragmentation (TMT) was used for the QMS analysis.
[0191] For each set the MS-raw data was merged during the search for protein identification
and relative quantification using Proteome Discoverer database. Due to the isobaric
chemical structure of the TMT tags, the peptides labeled with different tags was indistinguishable
during chromatographic separations and in MS mode. Each tag contained a characteristic
so-called reporter ion with a unique structure which is detectable upon fragmentation.
The ratio of these reporter ion intensities in MS3 spectra was used for quantification.
Only peptides unique for the specific protein were considered for quantification.
GSEA and related methods
[0192] To examine functional overlap among the genes that were differentially expressed
in the scaffold environment and the proteins represented in the tumor scaffolds, gene
set enrichment analysis (GSEA) was performed with the GSEA online tool
(http://software.broadinstitute.org/gsea/index.jsp) (
Subramanian, A., Tamayo, P., Mootha, V. K., Mukherjee, S. & Ebert, B. L. Gene set
enrichment analysis: A knowledge-based approach for interpreting genome-wide. Proc
Natl Acad Sci U S A 102, 15545-15550 (2005), using Reactome pathways (
Croft, D. et al. Reactome: A database of reactions, pathways and biological processes.
Nucleic Acids Res. 39, (2011)) and a q-value cutoff of 0.05.
References
[0196]
- 1. Thompson A, et al. Towards the development of a bioengineered uterus: Comparison of
different protocols for rat uterus decellularization. Acta Bio Material 12, 5034-5042,
(2014).
- 2. Ståhtberg, A. et al. RT-qPCR work-flow for single-cell data analysis. Methods. 59,
80-88 (2013).
- 3. Picelli, S. et al. Smart-seq2 for sensitive full-length transcriptome profiling in
single cells. Nat. Methods 10, 1096-8 (2013).
- 4. Jiang, L. et al. Synthetic spike-in standards for RNA-seq experiments. Genome Res.
21, 1543-51 (2011).
- 5. Dobin, A. et al. STAR: ultrafast universal RNA-seq aligner. Bioinformatics 29, 15-21
(2013).
- 6. Harrow, J. et al. GENCODE: The reference human genome annotation for the ENCODE project.
Genome Res. 22, 1760-1774 (2012).
- 7. Anders, S., Pyl, P. T. & Huber, W. HTSeq A Python framework to work with high-throughput
sequencing data. bioRxiv (2014). doi:10.1101/002824
- 8. Love, M. I., Huber, W. & Anders, S. Moderated estimation of fold change and dispersion
for RNA-seq data with DESeq2. Genome Biology (2014). doi: 10.1186/s13059-014-0550-8
- 9. Frances, L. Shaw et al.A Detailed Mammosphere Protocol for the Quantification of Breast
Stem Cell Activity. J Mammary Gland Biol Neoplasia. 17, 111-117 (2012)
Results
[0197] The rational for this project was to use the cell-free original breast cancer scaffolds
as templates for breast cancer cells to infiltrate within thereby creating an
in vivo like growth system that can be studied regarding tumor promoting features in relation
to scaffold composition and clinical origin. Initially, the inventors tested a standardized
decellurising protocol consisting of a prolonged mild detergent treatment potentially
preserving the basic scaffold composition optimally as described in Material and Methods.
The method was successfully adapted to breast cancer and scaffolds could reproducibly
be produced from various breast cancer types by the prolonged detergent wash protocol
(Figure 1). Scaffolds were indeed cell free, confirmed by extensive sectioning and
microscopic visualization as well as by DNA analyses (data not shown).
[0198] The composition of the cell free scaffolds obtained from breast cancer samples was
then delineated using mass spectrometry. 17 different scaffolds were submitted for
mass spectrometry analyses using the Sahlgrenska Academy core facility in Gothenburg
(details in Material and Methods). Since breast cancer is a heterogeneous disease
in many aspects the inventors noted major clinic-pathological parameter as grade,
proliferation, ER-positivity and HERs status in order to detect any differences in
composition linked to clinical subgroups. In total 145 different proteins were detected
in the various scaffolds including several expected proteins as various forms of collagen
and keratin but also more unexpected proteins (Table H). When using partial component
analyses (PCA) of the mass spectrometry identified scaffold proteins, two distinct
clusters of scaffolds was observed (Figure 2) supporting that breast cancer can be
subdivided into subgroups solely based on the composition of the cell-free scaffolds.
A dynamic PCA identified the key proteins responsible for the main clustering as illustrated
in Figure 3 and Figure 4 and includes proteins as periostin and dermatopontin as well
as various forms of collagen. Tumour grade and tumor proliferation measured by Ki67
further clustered together with one of the subgroups defined by for example FLNA and
TBA1C (Figure 3) supporting that the unsupervised clustering identified a cluster
that potentially was linked to tumour grade and tumour proliferation. When subdividing
the scaffolds according to high tumour grade versus lower grade and performing a dynamic
PCA (Figure 4) the inventors identified several proteins that effected the separation
and many of these proteins were similar to the proteins identified in the unsupervised
clustering of scaffolds. The unsupervised clustering was further partly overlapping
with clustering based on the proteins associated with grade and proliferation as illustrated
in Figure 4. Several proteins were significantly linked to these processes and periostin
was for example inversely linked to tumour grade (r = -0.49) and tumour cell proliferation
(Ki67, r = -0.44) whereas K6PL was positively associated to both grade (r=0.70) and
Ki67 (r=0.63). Additional proteins were further identified by collating all proteins
that were significantly linked to grade or proliferation in univariate analyses as
presented in Figure 5 clearly separating the two types of scaffolds. All key proteins
linked to the two subtypes of scaffolds overlapping with clinical aggressive features
as tumour grade and proliferation are listed in Tables B-F.
[0199] Next, the inventors tested how various breast cancer cell lines could survive and
potentially infiltrate as well as colonise the scaffolds. ER-negative cell lines as
the MDA-231 grew massively infiltrative in the scaffolds and created an
in vivo like tumour within three weeks (Figure 1). ER-positive breast cancer as MCF7 showed
less infiltrative capacity but created nests of tumour cells within some parts of
the scaffolds as well closer to the surface of the scaffolds (not shown). Cancer cells
from all cell lines tested showed active proliferation and survival as well signs
of various differentiation stages within the different patient scaffolds. MDA 231
cells lined up former vascular spaces with endothelial like cells and produced fibroblast
like cells as well as varying more breast cancer like cells in different areas of
the scaffolds (Figure1). Highly infiltrating cancer cells were commonly low proliferative
as illustrated by Ki-67 staining on sectioned scaffolds infiltrated by MDA231 cells
(figure 6). In summary, the inventors obtained reproducible cancer cell growth in
all initially tested scaffolds (n=26) supporting the stability of the growth platform
established.
[0200] In vivo growth of cancer is often characterized by lower proliferation in general
compared to regular cell cultures and a potentially different composition of differentiated
and cancer stem cell subpopulations. The inventors therefore wanted to detail the
existence of subgroups of cancer cells growing in scaffolds with a specific focus
on cancer stem cell and EMT properties. Interestingly, when analyzing several markers
for cancer stem cells, pluripotency, EMT, differentiation and proliferation in sets
of cancer cell lines grown in various scaffolds as well as under regular 2D conditions
it was clear that scaffolds cultures had higher expression of cancer stem cell and
pluripotency markers as SOX-2, NANOG and CD44. Proliferation and differentiation was
in contrast lowered in the scaffold cultures compared to 2D growing cells (Figure
7). These results suggest that cell lines dedifferentiated towards more cancer stem
cell and EMT features alternatively that these subgroups of cells selectively survived
better when infiltrating and encountering the cancer scaffolds. To verify these data
the inventors isolated cancer cells from three weeks of scaffolds cultures and performed
various surrogate cancer stem cell assay on these cells and compared the results with
the same cell line grown under regular 2D-conditions. The mammosphere assay is based
on the principle that progenitor and cancer stem cells are anoikis resistant under
non-adherent growth conditions and as illustrated in Figure 8, cells from scaffolds
had significantly higher mammosphere fractions compared to 2D-cultures. MDA231 breast
cancer cells from scaffolds and 2D growths were also injected subcutaneously in immunocompromised
NOG-mice and the tumour take and xenograft growth was monitored. In support for increased
cancer stem cell features in scaffolds the inventors also observed a significantly
increased tumour take in mice when injecting scaffold cells in comparison to 2D grown
cells (Figure 9). Finally, the inventors wanted to exactly monitor the composition
of various subgroups of cancer cells using a single-cell PCR approach and 96 cells
of 2D grown MCF7 cells as well as 96 cells from two independent scaffold cultures
using the same cell line were single cell sorted by flow cytometry and sets of markers
for cancer stem cell, pluripotency, differentiation, EMT and proliferation was measured
on each cell using a qPCR approach. The results showed that 2D grown control cell
mainly consisted of a large cluster of differentiated and highly proliferative cells
whereas the two scaffolds had a significantly increase in the less proliferative and
more stem cell defined clusters as indicated in Figure 10. These comprehensive data
clearly support that scaffold growth will promote cancer stem cell features and low
proliferative subpopulations lacking differentiation and was verified at the protein
level by Western Blotting indicating an increased protein expression of sox2 protein
in scaffold cultured breast cancer cells (Figure 11).
[0201] The kinetics of the changes in differentiation and proliferation was then studied
in a cell-free scaffold divided into several separate pieces. Breast cancer MCF7 and
MDA231 cells were grown on the pieces and samples were harvested day 1, 2, 3, 7, 14
and 21 and bulk qPCR analyses were performed using several markers for cancer stem
cells, EMT, differentiation and proliferation as outlined above. The results clearly
suggest that when cancer cells grow in scaffolds a highly coordinated and orchestrated
series of events is initiated resulting in high stem cell and EMT features paralleled
with low proliferation and drop of differentiation markers after three weeks of growth.
Interestingly, waves of activation and inactivation could be observed during growth
and at day one there was instant expression of cancer stem cell markers peaking early
followed by an EMT peak at day three and proliferation peak at day seven after an
initial drop as illustrated for MCF7 cells in figure 12. Differentiation markers declined
during growth and there was a final settling after 2-3 weeks with high stem cell/EMT
features and low proliferation/differentiation. The cancer stem cell changes were
consistent between the two cell lines whereas proliferation dropped later in MDA231
cells whereas the, for this subtype of cancer, less relevant differentiation markers,
did not change during growth (data not shown). The immediate increase in cancer stem
cell features of MCF7 cells grown on scaffolds suggest that cells initiate a dedifferentiation
process which will end up in a larger fraction of cancer stem cells after several
weeks of scaffolds growth.
[0202] Since there is huge need for relevant
in vivo like growth model systems for cancer studies and drug screening protocols that could
replace animal experiments the inventors next wanted to delineate similarities and
differences between 2D cultures, scaffold cultures and xenografts samples using next
generation sequencing (NGS) covering genome wide transcription. As illustrated in
Figure 13, plotting a selection of genes associated with cancer stem cells and EMT
features, there was indeed an increased expression of the majority of the plotted
genes validating the earlier described change in cancer stem cells in scaffold cultures.
PCA illustrations of the NGS data are presented in Figure 14 and scaffold cultures
clustered close to xenograft cultures and separate from 2D cultures. The two cell
lines separated in PC1 as expected but the relation between 2D, scaffold and xenograft
cultures were similar for the two cell lines verifying that scaffold and xenografts
were similar. The overlap and relation between the transcriptional changes as well
as effected processes for the various growth processes are illustrated in Figures
15, 16 and 17 supporting similarities as well as some differences between scaffold
and xenograft cultures. Typical processes upregulated in 2D growth conditions were
related to cell cycle and proliferation control whereas scaffolds were enriched for
immune systems, collagen formation and ECM organization. When comparing scaffolds
with xenografts there was a more pronounced upregulation of extracellular matrix organization,
PDGF signaling in the xenografts whereas ILS and TCR signaling was upregulated in
scaffolds to mention a few.
[0203] Since the inventors had detailed NGS data from cancer cells growing in scaffolds
as well as information about the protein composition of the scaffolds and some obvious
clusters as presented above they next wanted to identify potential links between the
protein scaffold data and expression differences in scaffolds compared to 2D using
a combined bioinformatics approach. Initial gene set enrichment analyses (GSEA) indicated
large overlaps between the pathways/reactomes enriched for among scaffold proteins
as well as the upregulated genes in the MCF7 and MDA231 cells. Of the top 10 most
significant reactomes in MCF7 cells, five were also among the top 10 in the scaffold
protein. For MDA 231, four out of ten were among this list clearly supporting functional
links between the identified scaffold proteins and regulated genes in cancer cells
growing in the scaffolds as summarized in Figure 18 for the top hundred reactomes.
When extending the pathway analyses of potential interactions for the identified proteins
in the scaffold including one additional protein level interaction for each protein,
three significant modules with overrepresented and associated processes were identified.
These modules were defined from the protein data and NGS data from MCF7 and MDA231
cells were then added, with links and key proteins and genes being identified in the
combined bioinformatics analyses. Module one represented "signaling" and consisted
of; signal transduction, signaling by SCF-KIT, downstream signal transduction and
signaling by VEGF, VEGFA-VEGFR2. Module 2 was "repair and stress" related and consisted
of DNA Repair, Cellular responses to stress, Cytosolic sensors of pathogen-associated
DNA, Generic Transcription Pathway and SUMOylation. Module 3 was "DNA-replication"
and included Synthesis of DNA, DNA Replication, M/G1 Transition and DNA Replication
Pre-Initiation. The key proteins in the scaffold responsible for the most central
processes as well as the separate modules are presented in Table G. Proteins and associated
genes in the two cell lines defined as representative for the central processes and
nodes thereby potentially highlighting key regulatory proteins and genes initiating
and mediating the observed changes in cancer stem cell and EMT features are also listed
in Table G.
[0204] It is clear that scaffolds in general will promote cancer stem cell and EMT features
as presented above but the question remains if there is varying capacities in different
scaffolds and if this potential difference is linked to a certain clinical behaviours
or clinical subgroups. To test this hypothesis the inventors analysed a series of
20 scaffolds for bulk-PCR expression data for four different breast cancer cell lines
grown three weeks on the scaffold. The PCR analyses included the same sets of markers
for stem cells, differentiation, EMT and proliferation as used earlier and the inventors
now wanted to compare the various scaffolds with regards to PCR changes in the "reporter"
cell line grown on the scaffolds with the general aim to identify subgroups of scaffolds
having more or less stem cell promoting capacities primarily. The data for T47D cells
is illustrated in Figure 19 and the scaffolds clearly separated in PC1 and PC2 whereas
the loading genes clustered in cancer stem cell and EMT associated genes on one side
and proliferation and differentiation linked genes on the opposite side. Similar findings
were observed with the other cell lines tested supporting that the capacity for different
scaffolds to induce cancer stem cell features vary (data not shown). These results
lead to a model where the inventors hypothesise that the patient scaffold can influence
various processes associated with tumour progression as illustrated in Figure 20 and
that this can be used as a test of the malignancy grade of that specific patient scaffold.
Since the first set of 20 scaffolds were obtained directly from surgery with very
limited follow-up time as well as material size the inventors could not investigate
if the ability to induce cancer stem cell and EMT features for the scaffolds were
linked to aggressiveness and cancer recurrences using this material. The inventors
therefore extended the studies and analysed biobanked and frozen breast cancer samples
with available longer follow-up data. Frozen samples could indeed be thawed and decellurised
with the defined protocol producing scaffolds that could be used to grow cells with
comparable PCR changes in the reporter cell line as freshly handled samples and scaffolds
(data not shown). The inventors therefore identified a material of 46 frozen ductal
breast cancer samples with available information about disease recurrences (median
clinical follow-up time of 29 months, range 94 months). Scaffolds were prepared from
the earlier frozen samples and MCF7 cells were grown on the scaffolds for three weeks
before qPCR analyses of genes representing key processes representative for subgroups
of cells present in MCF7 cells were performed. Some of the analysed genes (CCNB2,
EPCAM, POU5S1) did not pass the quality demands and were not included in the following
analyses. As illustrated in Figure 21 including several 2D controls and 46 scaffold
samples, all 2D control were separated from the scaffolds whereas scaffolds samples
spread in PCA1 and PCA2 indicating that the scaffolds possessed varying "difference"
from the 2D growth samples. When investigating how different genes effected the PCA
analyses, four clear clusters could be observed consisting of 1) Sox2 and CD44, 2)
SLUG and VIMENTIN, 3) CCNA2 and Ki67 and 4) ESR1 and ERBB2. When only analyzing the
scaffold samples without the 2D controls the inventors obtained similar clustering
and effects of genes and scaffold samples spread in PC1 and PC2 as illustrated in
Figure 22. Breast cancer recurrences are further indicated in the PC plot and there
was a clear overrepresentation of recurrences in the part of PC plot affected by SLUG
and VIMENTIN. There were further recurrences in the opposite and extreme direction
affected by differentiation and proliferation. When analyzing breast cancer recurrences
in relation to qPCR changes in MCF7 cells using Kaplan Meier plots and log rank analyses,
SLUG and VIMENTIN expression changes were also significantly linked to recurrences
using univariate analyses (p=0.02 and p=0.007 respectively) as illustrated in Figure
23 and 24. VIMENTIN was further independently linked to disease recurrences (p=0.03)
in a multi variate analyses including tumour grade, size, lymph-node metastases and
ER (Figure 24 indeed supporting that the information obtained from the scaffolds is
highly important in relation to conventional prognostic parameters.
[0205] These data suggest that it is mainly the EMT promoting effect of a scaffold that
is linked to breast cancer recurrences whereas more proliferation or pure cancer stem
cell promoting effects were not significantly linked to recurrences in this rather
limited tumor set only including ductal breast cancer. The data indeed highlight that
measurements of changes in a cell line grown in the scaffold can reveal important
and novel information about the malignancy and also support that the environment and
the scaffold will influence tumour promoting features that can be measured in the
developed growth platform and assay. Also when analyzing the data with a PCA-approach
and indicating scaffolds associated with breast cancer recurrences as illustrated
in Figure 22 it is clear that the disease recurrences are not evenly distributed in
the scatter but is overrepresented in the direction mostly affected by VIMENTIN and
SLUG expression.
Summary
[0206] Cancer cells are surrounded and actively interact with the microenvironment at the
primary site of growth as well as metastatic niches. Key components in the cancer
environment have been linked to various aggressive cancer features and can further
influence the essential subpopulation of cancer stem cells most likely governing malignant
properties and treatment resistance. In order to identify and specifically enumerate
the influence of a specific cancer microenvironment the inventors have developed and
characterized a novel cell culture platform using cell free scaffolds from primary
breast cancer samples infiltrated with breast cancer cells. This
in vivo like growth system induced a series of orchestrated changes in differentiation, EMT
and proliferation of the cancer population with a final remarkable cancer stem cell
expansion as defined by several surrogate assays and functional tests. Scaffold cultures
were further more similar to xenograft cultures compared to regular 2D cultures as
illustrated by NGS-analyses supporting an
in vivo like growth in the scaffolds.
[0207] Despite a general promotion of cancer stem cell features in scaffolds, the ability
varied and some scaffolds induced more EMT features whereas others preserved a differentiated
and proliferative phenotype of cancer cells. Mass spectrometry analyses of cell-free
scaffolds further identified subgroups of scaffolds based on the protein composition
that also mirrored clinical properties such as tumour grade, supporting scaffold based
micro environmental heterogeneity.
[0208] By combining the mass spectrometry data with NGS analyses identifying transcriptional
changes in the cancer cells, the inventors could identify central processes and over
represented modules both regarding proteins in the scaffold as well as key regulatory
events in the cancer cell lines further supporting the existence of subgroups of scaffolds.
[0209] A theoretically important read-out of the scaffold platform is the varying ability
for the scaffold to induce specific changes in cancer cells and the potential link
to clinical behaviours and properties and this was studied in a material of 47 earlier
frozen breast cancer samples with available clinical follow-up. Interestingly, EMT
induced changes as represented by an increase of SLUG or Vimentin in the breast cancer
cell line MCF7 growing in the scaffolds, was significantly linked to breast cancer
recurrences and aggressive properties of the donor breast cancer (Vimentin, p=0.03,
multivariate analyses).
[0210] The developed scaffold model system has the potential to optimally mimic in vivo
like growth conditions revealing hidden and highly relevant clinical information about
the malignancy inducing property of the specific scaffold earlier surrounding and
indeed influencing cancer progressing properties.
Tables A-H
[0211]
Table A - Tumour Progression Marker Genes
Accession/Version Numbers are with respect to the National Center for Biotechnology
Information (NCBI) database as at 1 November 2016. |
|
Marker Gene Name |
Accession Number |
Version Number |
Proliferation Markers |
|
|
|
CCNB2 |
NM_004701 |
NM_004701.3 |
CCNA2 |
NM_001237 |
NM_001237.4 |
CDKN1A |
NM_000389 |
NM_000389.4 |
CDKN2A |
NM_000077 |
NM_000077.4 |
MKi67 |
NM_001145966 |
NM_001145966.1 |
CDK4 |
NM_000075 |
NM_000075.3 |
CDK6 |
NM_001145306 |
NM_001145306.1 |
|
|
|
|
Differentiation Markers |
|
|
|
EPCAM |
NM_002354 |
NM_002354.2 |
PGR |
NM_000926 |
NM_000926.4 |
ESR1 |
NM_000125 |
NM_000125.3 |
CD24 |
NM_013230 |
NM_013230.3 |
CDH1 |
NM_001317184 |
NM_001317184.1 |
ERBB2 |
NM_001005862 |
NM_001005862.2 |
|
|
|
|
Cancer stem cell/pluripotency Markers |
|
|
|
POU5F1 |
NM_002701 |
NM_002701.5 |
NANOG |
NM_024865 |
NM_024865.3 |
SOX2 |
NM_003106 |
NM_003106.3 |
FOSL1 |
NM_005438 |
NM_005438.4 |
TGFB1 |
NM_000660 |
NM_000660.6 |
CD44 |
NM_000610 |
NM_000610.3 |
ALDH1A1 |
NM_000689 |
NM_000689.4 |
ALDH1A3 |
NM_000693 |
NM_000693.3 |
ABCG2 |
NM_004827 |
NM_004827.2 |
|
|
|
|
EMT Markers |
|
|
|
SNAIL1 |
NM_005985 |
NM_005985.3 |
TWIST1 |
NM_000474 |
NM_000474.3 |
SNAIL2 |
NM_003068 |
NM_003068.4 |
VIM |
NM_003380 |
NM_003380.3 |
CDH2 |
NM_001792 |
NM_001792.4 |
Tables B-F - Key proteins identified in the scaffolds linked to subtypes of scaffolds, grade and
key processes
[0212] The Tables list proteins identified by dynamic PCA of mass spectrometry data identifying
Cluster 1 and Cluster 2, as well as proteins significantly linked to tumour grade
or tumour proliferation (Ki67). Directions of associations are shown within brackets.
There is overlap between PCA Cluster 2 and high grade/proliferation. Accession/Version
Numbers are with respect to SwissProt_2015_04_verINS.fasta Version: 2.3, as at 29
October 2016.
Table B
|
Protein Name |
Accession Number |
Database Version Number |
PCA Cluster 1 |
|
|
|
POSTN |
Q15063 |
Q15063.2 |
ANXA5 |
P08758 |
P08758.2 |
PRELP |
P51888 |
P08758.2 |
MYO1C |
O00159 |
O00159.4 |
CD47 |
Q08722 |
Q08722.1 |
FBLN2 |
P98095 |
P98095.2 |
SNG2 |
O43760 |
O43760.1 |
DERM |
P35908 |
P35908.2 |
IGHA1 |
P01876 |
P01876.2 |
ITIH1 |
P19827 |
P19827.3 |
SC22B |
O75396 |
O75396.4 |
SAMP |
P02743 |
P02743.2 |
LUM |
P51884 |
P51884.2 |
PGS1 |
P21810 |
P21810.2 |
COL6A2 |
P12110 |
P12110.4 |
COL6A3 |
P12111 |
P12111.5 |
COL6A1 |
P12109 |
P12109.3 |
ALBU |
P02768 |
P02768.2 |
TM109 |
Q9BVC6 |
Q9BVC6.1 |
K22E |
P35908 |
P35908.2 |
|
|
|
|
PCA Cluster 2 |
ENPL |
P14625 |
P14625.1 |
CH60 |
P10809 |
P10809.2 |
CKAP4 |
Q07065 |
Q07065.2 |
HS90A |
P07900 |
P07900.5 |
ENOA |
P06733 |
P06733.2 |
HS90B |
P08238 |
P08238.4 |
G3P |
P04406 |
P04406.3 |
K6PL |
P17858 |
P17858.6 |
HSP7C |
P11142 |
P11142.1 |
IF4A1 |
P60842 |
P60842.1 |
TBA1C |
Q9BQE3 |
Q9BQE3.1 |
HNRPQ |
O60506 |
O60506.2 |
DX39B |
Q13838 |
Q13838.1 |
HNRPF |
P52597 |
P52597.3 |
EF1A1 |
P68104 |
P68104.1 |
TBB5 |
P07437 |
P07437.2 |
HSPB1 |
P04792 |
P04792.2 |
FLNA |
P21333 |
P21333.4 |
LMAN1 |
P49257 |
P49257.2 |
MYH9 |
P35579 |
P35579.4 |
ACTB |
P60709 |
P60709.1 |
TBB5 |
P07437 |
P07437.2 |
RS3 |
P23396 |
P23396.2 |
Table C -
Proteins significantly linked to high proliferation (p=0.01-0.05)
Protein Name |
Positive or negative association |
Accession Number |
Version Number |
K6PL |
+ |
P17858 |
P17858.6 |
HS90A |
+ |
P07900 |
P07900.5 |
IF4A1 |
+ |
P60842 |
P60842.1 |
PGS1 |
- |
P21810 |
P21810.2 |
ENOA |
+ |
P06733 |
P06733.2 |
PRELP |
- |
P51888 |
P51888.1 |
SNG2 |
- |
O43760 |
O43760.1 |
CH60 |
+ |
P10809 |
P10809.2 |
LUM |
- |
P16615 |
P16615.1 |
HS90B |
+ |
P08238 |
P08238.4 |
Table D - Proteins most significantly linked to high proliferation (p<0.01)
Protein Name |
Positive or negative association |
Accession Number |
Version Number |
K6PL |
+ |
P17858 |
P17858.6 |
HS90A |
+ |
P07900 |
P07900.5 |
IF4A1 |
+ |
P60842 |
P60842.1 |
Table E - Proteins significantly linked to high grade (p=0.01-0.05)
Protein Name |
Positive or negative association |
Accession Number |
Version Number |
HS90A |
+ |
P07900 |
P07900.5 |
ENOA |
+ |
P06733 |
P06733.2 |
HS90B |
+ |
P08238 |
P08238.4 |
IF4A1 |
+ |
P60842 |
P60842.1 |
K6PL |
+ |
P17858 |
P17858.6 |
PRELP |
- |
P51888 |
P51888.1 |
SNG2 |
- |
O43760 |
O43760.1 |
CD47 |
- |
Q08722 |
Q08722.1 |
PGS1 |
- |
P21810 |
P21810.2 |
CH60 |
+ |
P10809 |
P10809.2 |
TBA1C |
+ |
Q9BQE3 |
Q9BQE3.1 |
HSP7C |
+ |
P11142 |
P11142.1 |
Table F - Proteins most significantly linked to high grade (p<0.01)
Protein Name |
Positive or negative association |
Accession Number |
Version Number |
HSP90A |
+ |
P07900 |
P07900.5 |
ENOA |
+ |
P06733 |
P06733.2 |
HS90B |
+ |
P08238 |
P08238.4 |
IF4A1 |
+ |
P60842 |
P60842.1 |
K6PL |
+ |
P17858 |
P17858.6 |
PRELP |
- |
P51888 |
P51888.1 |
SNG2 |
- |
O43760 |
O43760.1 |
Table G - List of proteins and linked up- or down-regulated genes from NGS-data in MCF7 and
MDA231 cells, in the three different modules identified by GSEA-analyses. A summary
of the most central genes of interest and the linked scaffold proteins is further
listed.