The cellular origin of Ewing tumor (ET), a tumor of bone or soft tissues characterized by specific fusions between EWS and ETS genes, is highly debated. Through gene expression analysis comparing ETs with a variety of normal tissues, we show that the profiles of different EWS-FLI1-silenced Ewing cell lines converge toward that of mesenchymal stem cells (MSC). Moreover, upon EWS-FLI1 silencing, two different Ewing cell lines can differentiate along the adipogenic lineage when incubated in appropriate differentiation cocktails. In addition, Ewing cells can also differentiate along the osteogenic lineage upon long-term inhibition of EWS-FLI1. These in silico and experimental data strongly suggest that the inhibition of EWS-FLI1 may allow Ewing cells to recover the phenotype of their MSC progenitor.
Mesenchymal stem cell features of Ewing tumors.
Specimen part
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Sox9 Controls Self-Renewal of Oncogene Targeted Cells and Links Tumor Initiation and Invasion.
Specimen part
View SamplesSox9 is a transcription factor expressed in most solid tumors. However, the molecular mechanisms underlying Sox9 function during tumorigenesis remain unclear. Here, using a genetic mouse model of basal cell carcinoma (BCC), the most frequent cancer in human, we show that Sox9 is expressed from the earliest step of tumor formation in a Wnt/-catenin dependent manner. Deletion of Sox9 together with the constitutive activation of Hedgehog (HH) signaling completely prevents BCC formation and leads to a progressive loss of oncogene expressing cells. Transcriptional profiling of oncogene expressing cells with Sox9 deletion, combined with in vivo ChIP-sequencing uncovers a cancer-specific gene network regulated by Sox9 that promotes stemness, extracellular matrix (ECM) deposition and cytoskeleton remodeling while repressing epidermal differentiation. Our study identifies the molecular mechanisms regulated by Sox9 that links tumor initiation and invasion.
Sox9 Controls Self-Renewal of Oncogene Targeted Cells and Links Tumor Initiation and Invasion.
Specimen part
View SamplesCancer stem cells (CSCs) have been reported in various cancers including skin squamous cell carcinoma (SCC). The molecular mechanisms regulating tumour initiation and stemness are still poorly characterized. Here, we found that Sox2, a transcription factor expressed in various types of embryonic and adult stem cells (SCs), was the most upregulated transcription factor in CSCs of squamous skin tumours. Sox2 is absent in normal epidermis and begins to be expressed in the vast majority of mouse and human pre-neoplastic skin tumours and continues to be expressed in a heterogeneous manner in invasive mouse and human SCCs. In contrast to other SCCs, in which Sox2 is frequently genetically amplified, the expression of Sox2 in mouse and human skin SCCs is transcriptionally regulated. Conditional deletion of Sox2 in the mouse epidermis dramatically decreases skin tumour formation following chemical induced carcinogenesis. Using Sox2-GFP knockin mice, we showed that Sox2 expressing cells in invasive SCC are greatly enriched in tumour propagating cells (TPCs) that further increase upon serial transplantations. Lineage ablation of Sox2 expressing cells within primary benign and malignant SCCs leads to tumour regression, consistent with the critical role of Sox2 expressing cells in tumour maintenance. Conditional Sox2 deletion in pre-existing skin papilloma and SCC leads to their regression and decreases their ability to be propagated upon transplantation into immunodeficient mice, supporting the essential role of Sox2 in regulating CSC functions. Transcriptional profiling of Sox2-GFP expressing CSC and upon Sox2 deletion uncovered a gene network regulated by Sox2 in primary tumour cells in vivo. Chromatin immunoprecipitation identified several direct Sox2 target genes controlling tumour stemness, survival, proliferation, adhesion, invasion, and paraneoplastic syndrome. Altogether, our study demonstrates that Sox2, by marking and regulating the functions of skin tumour initiating cells and CSCs, establishes a continuum between tumour initiation and progression in primary skin tumours.
SOX2 controls tumour initiation and cancer stem-cell functions in squamous-cell carcinoma.
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View SamplesCancer stem cells (CSCs) have been reported in various cancers including skin squamous cell carcinoma (SCC). The molecular mechanisms regulating tumour initiation and stemness are still poorly characterized. Here, we found that Sox2, a transcription factor expressed in various types of embryonic and adult stem cells (SCs), was the most upregulated transcription factor in CSCs of squamous skin tumours. Sox2 is absent in normal epidermis and begins to be expressed in the vast majority of mouse and human pre-neoplastic skin tumours and continues to be expressed in a heterogeneous manner in invasive mouse and human SCCs. In contrast to other SCCs, in which Sox2 is frequently genetically amplified, the expression of Sox2 in mouse and human skin SCCs is transcriptionally regulated. Conditional deletion of Sox2 in the mouse epidermis dramatically decreases skin tumour formation following chemical induced carcinogenesis. Using Sox2-GFP knockin mice, we showed that Sox2 expressing cells in invasive SCC are greatly enriched in tumour propagating cells (TPCs) that further increase upon serial transplantations. Lineage ablation of Sox2 expressing cells within primary benign and malignant SCCs leads to tumour regression, consistent with the critical role of Sox2 expressing cells in tumour maintenance. Conditional Sox2 deletion in pre-existing skin papilloma and SCC leads to their regression and decreases their ability to be propagated upon transplantation into immunodeficient mice, supporting the essential role of Sox2 in regulating CSC functions. Transcriptional profiling of Sox2-GFP expressing CSC and upon Sox2 deletion uncovered a gene network regulated by Sox2 in primary tumour cells in vivo. Chromatin immunoprecipitation identified several direct Sox2 target genes controlling tumour stemness, survival, proliferation, adhesion, invasion, and paraneoplastic syndrome. Altogether, our study demonstrates that Sox2, by marking and regulating the functions of skin tumour initiating cells and CSCs, establishes a continuum between tumour initiation and progression in primary skin tumours.
SOX2 controls tumour initiation and cancer stem-cell functions in squamous-cell carcinoma.
Specimen part
View SamplesThe identification of subtype-specific translocations has revolutionized diagnostics of sarcoma and provided new insight into oncogenesis. We used RNA-Seq to investigate samples diagnosed as small round cell tumors of bone, possibly Ewing sarcoma, but lacking the canonical EWSR1-ETS translocation. A new fusion was observed between the BCL6 co-repressor (BCOR) and the testis specific cyclin B3 (CCNB3) genes on chromosome X. RNA-Seq results were confirmed by RT-PCR and cloning the tumor-specific genomic translocation breakpoints. 24 BCOR-CCNB3-positive tumors were identified among a series of 594 sarcomas. Gene profiling experiments indicate that BCOR-CCNB3-positive cases are biologically distinct from other sarcomas, particularly Ewings sarcoma. Finally, we show that CCNB3 immunohistochemistry is a powerful diagnostic marker for this group of sarcoma and that over-expression of BCOR-CCNB3 or of a truncated CCNB3 activates S-phase in NIH3T3 cells. Thus the intrachromosomal X fusion described here represents a new subtype of bone sarcoma caused by a novel gene fusion mechanism.
A new subtype of bone sarcoma defined by BCOR-CCNB3 gene fusion.
Sex, Age, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
5-hydroxymethylcytosine marks promoters in colon that resist DNA hypermethylation in cancer.
Sex, Specimen part, Cell line, Treatment, Subject
View SamplesThe discovery of cytosine hydroxymethylation (5-hmC) as a mechanism that potentially controls DNA methylation changes typical of neoplasia prompted us to investigate its behavior in colon cancer. 5-hmC is globally reduced in proliferating cells such as colon tumors and the gut crypt progenitors, from which tumors can arise. Here, we show that colorectal tumors and cancer cells express Ten-Eleven Translocation (TET) transcripts at levels similar to normal tissues. Genome-wide analyses show that promoters marked by 5-hmC in normal tissue, and those identified as TET2 targets in colorectal cancer cells, are resistant to methylation gain in cancer. In vitro studies of TET2 in cancer cells confirm that these promoters are resistant to methylation gain independently of sustained TET2 expression. We also find that a considerable number of the methylation gain-resistant promoters marked by 5-hmC in normal colon overlap with those that are marked with poised bivalent histone modifications in embryonic stem cells. Together our results indicate that promoters that acquire 5-hmC upon normal colon differentiation are innately resistant to neoplastic hypermethylation by mechanisms that do not require high levels of 5-hmC in tumors. Our study highlights the potential of cytosine modifications as biomarkers of cancerous cell proliferation.
5-hydroxymethylcytosine marks promoters in colon that resist DNA hypermethylation in cancer.
Sex, Specimen part, Subject
View SamplesPolarity defects are a hallmark of most carcinomas. Cells from invasive micropapillary carcinomas (IMPCs) of the breast are characterized by a striking cell polarity inversion and represent a good model for the analysis of polarity abnormalities. We have performed an in-depth investigation of polarity alterations in 24 IMPCs, compared with invasive carcinomas of no special type (ICNST).
LIN7A is a major determinant of cell-polarity defects in breast carcinomas.
Specimen part
View SamplesIdentification of druggable targets is a prerequisite for developing targeted therapies against Ewing sarcoma. We report the identification of Protein Kinase C Beta (PRKCB) as a protein specifically and highly expressed in Ewing sarcoma as compared to other pediatric cancers. Its transcriptional activation is directly regulated by the EWSR1-FLI1 oncogene. Getting insights in PRKCB activity we show that, together with PRKCA, it is responsible for the phosphorylation of histone H3T6, allowing global maintenance of H3K4 trimethylation on a variety of gene promoters. In the long term, PRKCB RNA interference induces apoptosis in vitro. More importantly, in xenograft mice models, complete impairment of tumor engraftment and even tumor regression were observed upon PRKCB inhibition, highlighting PRKCB as a most valuable therapeutic target. Deciphering PRKCB roles in Ewing sarcoma using expression profiling, we found a strong overlap with genes modulated by EWSR1-FLI1 and an involvement of RPKCB in regulating crucial signaling pathways. Altogether, we show that PRKCB may have two important independent functions and should be considered as highly valuable for understanding Ewing sarcoma biology and as a promising target for new therapeutic approaches in Ewing sarcoma.
Targeting the EWSR1-FLI1 oncogene-induced protein kinase PKC-β abolishes ewing sarcoma growth.
Cell line
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