Primary tumor growth induces host tissue responses that are believed to support and promote tumor progression. Identification of the molecular characteristics of the tumor microenvironment and elucidation of its crosstalk with tumor cells may therefore be crucial for improving our understanding of the processes implicated in cancer progression, identifying potential therapeutic targets, and uncovering stromal gene expression signatures that may predict clinical outcome. A key issue to resolve, therefore, is whether the stromal response to tumor growth is largely a generic phenomenon, irrespective of the tumor type, or whether the response reflects tumor-specific properties. To address similarity or distinction of stromal gene expression changes during cancer progression, oligonucleotide-based Affymetrix microarray technology was used to compare the transcriptomes of laser-microdissected stromal cells derived from invasive human breast and prostate carcinoma. Invasive breast and prostate cancer-associated stroma was observed to display distinct transcriptomes, with a limited number of shared genes. Interestingly, both breast and prostate tumor-specific dysregulated stromal genes were observed to cluster breast and prostate cancer patients, respectively, into two distinct groups with statistically different clinical outcomes. By contrast, a gene signature that was common to the reactive stroma of both tumor types did not have survival predictive value. Univariate Cox analysis identified genes whose expression level was most strongly associated with patient survival. Taken together, these observations suggest that the tumor microenvironment displays distinct features according to the tumor type that provides survival-predictive value.
Identification of prognostic molecular features in the reactive stroma of human breast and prostate cancer.
Specimen part
View SamplesMetastasis depends on the ability of tumor cells to establish a relationship with the newly seeded host tissue that is conducive to their survival and proliferation. Recent evidence suggests that tumor cells regulate their own dissemination by preparing permissive metastatic niches within host tissues. However, the factors that are implicated in rendering tissues permissive for metastatic tumor growth have yet to be fully elucidated. Breast tumors arising during pregnancy display highly aggressive behaviour and early metastatic proclivity, raising the possibility that pregnancy may constitute a physiological condition of permissiveness for tumor dissemination. We show that during murine gestation, both the rate and degree of metastatic tumor growth are enhanced irrespective of tumor type and that decreased natural killer (NK) cell activity is responsible for the observed increase in experimental metastasis. We identify gene expression changes in pregnant mouse lung and liver that bear striking similarity with reported pre-metastatic niche signatures and several of the up-regulated genes are indicative of myeloid-cell infiltration. We provide evidence, that CD11b+ Gr-1+ myeloid-derived suppressor cells accumulate in pregnant mice and exert an inhibitory effect on NK cell activity, thereby enhancing metastatic tumor growth. MDSC have never been evoked in the context of pregnancy and our observations suggest that they may represent a further shared mechanism of immune suppression occurring during gestation and tumor growth.
Myeloid-derived suppressor cells are implicated in regulating permissiveness for tumor metastasis during mouse gestation.
Specimen part
View SamplesWe implemented an optimized processing, using alternative Chip Description Files (CDFs) and fRMA normalization, which improve the quality of downstream analysis.
Accurate data processing improves the reliability of Affymetrix gene expression profiles from FFPE samples.
Specimen part
View SamplesSTAT3 is a transcription factor playing a crucial role in inflammation, immunity and oncogenesis, able to induce distinct subsets of target genes in different cell types or under different conditions. Identification of direct transcriptional targets however has only defined a relatively limited set of genes, not sufficient to explain its variegated functions. In order to improve our understanding of the STAT3 transcriptional network we decided to develop a computational approach for the discovery of STAT3 functional binding sites. Upon generating a Positional Weight Matrix to define STAT3 binding sites, we applied a loglikelihood ratio scoring function and were able to assign affinity scores with very high specificity (93.5%) as measured by EMSA. STAT3 binding sites scoring above a stringent threshold have been identified genome-wide in Homo sapiens and Mus musculus and selected for phylogenetic conservation by genomic sequence alignment using eight vertebrate species. Validation was carried out on a subset of predicted
Genome-wide discovery of functional transcription factor binding sites by comparative genomics: the case of Stat3.
No sample metadata fields
View SamplesPhenotypic changes induced by extracellular vesicles (EVs) have been implicated in the recovery of acute kidney injury (AKI) induced by mesenchymal stromal cells (MSCs). miRNAs are potential candidates for cell reprogramming towards a pro-regenerative phenotype. The aim of the present study was to evaluate whether miRNA de-regulation inhibits the regenerative potential of MSCs and derived-EVs in a model of glycerol-induced AKI in SCID mice. For this purpose, we generated MSCs depleted of Drosha, a critical enzyme of miRNA maturation, to alter miRNA expression within MSCs and EVs. Drosha knock-down MSCs (MSC-Dsh) maintained the phenotype and differentiation capacity. They produced EVs that did not differ from those of wild type cells in quantity, surface molecule expression and internalization within renal tubular epithelial cells. However, EVs derived from MSC-Dsh (EV-Dsh) showed global down-regulation of miRNAs. Whereas, wild type MSCs and derived EVs were able to induce morphological and functional recovery in AKI, MSC-Dsh and EV-Dsh were ineffective. RNA sequencing analysis showed that genes deregulated in the kidney of AKI mice were restored by treatment with MSCs and EVs but not by MSC-Dsh and EV-Dsh. Gene Ontology analysis showed that down-regulated genes in AKI were associated with fatty acid metabolism. The up-regulated genes in AKI were involved in inflammation, ECM-receptor interaction and cell adhesion molecules. These alterations were reverted by treatment with wild type MSCs and EVs, but not by the Drosha counterparts. In conclusion, miRNA depletion in MSCs and EVs significantly reduced their intrinsic regenerative potential in AKI, suggesting a critical role of miRNAs. Overall design: RNA-seq
AKI Recovery Induced by Mesenchymal Stromal Cell-Derived Extracellular Vesicles Carrying MicroRNAs.
No sample metadata fields
View SamplesExpression of the SS18/SYT-SSX fusion protein is believed to underlie the pathogenesis of synovial sarcoma (SS). Recent evidence suggests that deregulation of the Wnt pathway may play an important role in SS but the mechanisms whereby SS18-SSX might affect Wnt signaling remain to be elucidated. Here, we show that SS18/SSX tightly regulates the elevated expression of the key Wnt target AXIN2 in primary SS. SS18-SSX is shown to interact with TCF/LEF, TLE and HDAC but not -catenin in vivo and to induce Wnt target gene expression by forming a complex containing promoter-bound TCF/LEF and HDAC but lacking -catenin. Our observations provide a tumor-specific mechanistic basis for Wnt target gene induction in SS that can occur in the absence of Wnt ligand stimulation.
The fusion protein SS18-SSX1 employs core Wnt pathway transcription factors to induce a partial Wnt signature in synovial sarcoma.
Cell line
View SamplesSenescence of stromal fibroblasts has been linked to establishment of cancer associated fibroblasts (CAF) and aging-associated increase of tumors. However, in clinically occurring carcinomas, density and proliferation of CAFs are frequently increased rather than decreased. We previously showed that genetic deletion or down-modulation of the canonical Notch effector CSL/RBP-J? in skin dermal fibroblasts is sufficient for CAF activation with consequent development of multifocal keratinocyte tumors. We now show that CSL deletion or knockdown induces senescence of primary fibroblasts derived from dermis, oral mucosa, breast and lung. CSL functions in these cells as a constitutive direct repressor of multiple senescence- and CAF-effector genes. At the same time, it physically interacts with p53, repressing its activity, and p53 activation provides a failsafe mechanism against compromised CSL function. Concomitant loss of CSL and p53 overcomes fibroblast senescence, enhances expression of CAF effector genes and, in vivo, promotes tumour and stromal cell expansion. Together, the findings support a CAF activation/stromal evolution model under convergent CSL/p53 control. Overall design: Human Dermal Fibroblasts were transfected with two different siRNA against CSL in parallel with a control siRNA. Total RNA was extracted 3 days post-transfection, followed by RNA-Seq analysis.
Combined CSL and p53 downregulation promotes cancer-associated fibroblast activation.
No sample metadata fields
View SamplesSenescence of stromal fibroblasts has been linked to establishment of cancer associated fibroblasts (CAF) and aging-associated increase of tumors. However, in clinically occurring carcinomas, density and proliferation of CAFs are frequently increased rather than decreased. We previously showed that genetic deletion or down-modulation of the canonical Notch effector CSL/RBP-J-kappa in skin dermal fibroblasts is sufficient for CAF activation with consequent development of multifocal keratinocyte tumors. We now show that CSL deletion or knockdown induces senescence of primary fibroblasts derived from dermis, oral mucosa, breast and lung. CSL functions in these cells as a constitutive direct repressor of multiple senescence- and CAF-effector genes. At the same time, it physically interacts with p53, repressing its activity, with p53 activation providing a failsafe mechanism against compromised CSL function. Concomitant loss of CSL and p53 overcomes fibroblasts senescence, enhances CAF effector gene expression and, in vivo, promotes stromal and cancer cell expansion. Together, these findings support a CAF activation/stromal evolution model under convergent CSL/p53 control.
Combined CSL and p53 downregulation promotes cancer-associated fibroblast activation.
Specimen part
View SamplesLung cancer is a highly malignant tumor and the majority of cancer-related deaths are due to metastasis. The tumor microenvironment (TME) plays a fundamental role in the metastatic spread of tumor cells. Among other stromal cells, mesenchymal stem cells (MSCs) are known to be present within the TME and to be involved in cancer progression. However the majority of previous studies have been performed on bone marrow-derived MSCs. To investigate the role of the TME on the pulmonary MSC phenotype, we compared the expression profile of paired MSCs isolated from lung tumor (T-) and normal adjacent tissues (N-) from lung carcinoma patients.
Reciprocal modulation of mesenchymal stem cells and tumor cells promotes lung cancer metastasis.
Specimen part, Disease stage, Subject
View SamplesThe transcription factor STAT3 is constitutively activated in tumors of different origin but the molecular bases for STAT3 addiction of tumor cells have not yet been clearly identified. We generated knock/in mice carrying the constitutively active Stat3 allele, Stat3C, and showed that Stat3C could enhance Neu oncogenic power, triggering the production of earlier onset, more invasive mammary tumors. Tumor-derived cell lines displayed higher migration and invasion and disrupted distribution of cell-cell junction markers. The tensin family member Cten (C-Terminal Tensin-like), known to mediate EGF-induced migration and highly expressed in inflammatory breast cancer, was up-regulated in both Neu;Stat3C cells and tumors. Both Cten expression and enhanced migration were strictly dependent on Stat3, and Cten silencing normalized cell migration and rescued cell-cell contact defects. Importantly, the pro-inflammatory cytokine IL-6 could mediate Cten induction in MCF10 cells, in an exquisitely Stat3-dependent way. This model allowed us to shed some light on the oncogenic role of Stat3 in the breast, suggesting moreover a mechanism through which inflammatory signals can cooperate with EGF receptors in inflammatory breast cancer.
Constitutively active Stat3 enhances neu-mediated migration and metastasis in mammary tumors via upregulation of Cten.
No sample metadata fields
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