Project description:Normal human mammary epithelial cell (HMLE) and breast cancer MDA-MB-231 cells are engineered to knockdown or enforce expression of variety of LCOR gene products. In addition to wild-type cDNA, functional domain deficient mutants were used to elucidate mechanism of LCOR incorporated transcriptional regulation. The transcriptome profiles were determined and compared.
Project description:LCOR is a tumor suppressor that induces differentiation of mammary stem cells and cancer stem cells. LCOR orchestrates and sensitizes cells to interferon in ER-negative breast cancer cells. LCOR can act as a co-repressor of activated nuclear receptors and also as a transcription factor by DNA direct binding through its HTH domain. These domains are the most conserved regions of LCOR across vertebrates, suggesting a conserved regulatory function. Here we performed ChiP-seq analysis of LCOR in MDA-MB-231 cells with ectopic expression of the LCOR wild-type, LCOR without the nuclear receptor binding domain (LSKAA) and LCOR with deleted DNA binding domain (HTH). This analysis allows to compare the genome wide distribution of LCOR depending on these specific protein domains
Project description:We previously identified a gene signature predicted to regulate the epithelial-mesenchymal transition (EMT) in both epithelial tissue stem cells and breast cancer cells. A phenotypic RNA interference (RNAi) screen identified the genes within this 140-gene signature that promoted the conversion of mesenchymal epithelial cell adhesion molecule-negative (EpCAM-) breast cancer cells to an epithelial EpCAM+/high phenotype. The screen identified 10 of the 140 genes whose individual knockdown was sufficient to promote EpCAM and E-cadherin expression. Among these 10 genes, RNAi silencing of the SWI/SNF chromatin-remodeling factor Smarcd3/Baf60c in EpCAM- breast cancer cells gave the most robust transition from the mesenchymal to epithelial phenotype. Conversely, expression of Smarcd3/Baf60c in immortalized human mammary epithelial cells induced an EMT. The mesenchymal-like phenotype promoted by Smarcd3/Baf60c expression resulted in gene expression changes in human mammary epithelial cells similar to that of claudin-low triple-negative breast cancer cells. These mammary epithelial cells expressing Smarcd3/Baf60c had upregulated Wnt5a expression. Inhibition of Wnt5a by either RNAi knockdown or blocking antibody reversed Smarcd3/Baf60c-induced EMT. Thus, Smarcd3/Baf60c epigenetically regulates EMT by activating WNT signaling pathways. sampleXreference
Project description:We previously identified a gene signature predicted to regulate the epithelial-mesenchymal transition (EMT) in both epithelial tissue stem cells and breast cancer cells. A phenotypic RNA interference (RNAi) screen identified the genes within this 140-gene signature that promoted the conversion of mesenchymal epithelial cell adhesion molecule-negative (EpCAM-) breast cancer cells to an epithelial EpCAM+/high phenotype. The screen identified 10 of the 140 genes whose individual knockdown was sufficient to promote EpCAM and E-cadherin expression. Among these 10 genes, RNAi silencing of the SWI/SNF chromatin-remodeling factor Smarcd3/Baf60c in EpCAM- breast cancer cells gave the most robust transition from the mesenchymal to epithelial phenotype. Conversely, expression of Smarcd3/Baf60c in immortalized human mammary epithelial cells induced an EMT. The mesenchymal-like phenotype promoted by Smarcd3/Baf60c expression resulted in gene expression changes in human mammary epithelial cells similar to that of claudin-low triple-negative breast cancer cells. These mammary epithelial cells expressing Smarcd3/Baf60c had upregulated Wnt5a expression. Inhibition of Wnt5a by either RNAi knockdown or blocking antibody reversed Smarcd3/Baf60c-induced EMT. Thus, Smarcd3/Baf60c epigenetically regulates EMT by activating WNT signaling pathways.
Project description:Epithelial cells possess remarkable plasticity, having the ability to become mesenchymal cells through alterations in adhesion and motility (epithelial-to-mesenchymal transition or EMT). Recent studies suggest that EMT endows differentiated epithelial cells with stem cell traits, posing the interesting question of how epithelial plasticity is properly restricted to ensure epithelial differentiation during tissue morphogenesis. Here we identify zinc-finger transcription factor Ovol2 as a key suppressor of EMT of mammary epithelial cells. Epithelia-specific deletion of Ovol2 completely arrests mammary ductal morphogenesis, and depletes epithelial stem/progenitor cell reservoirs. Further, Ovol2-deficient epithelial cells undergo EMT in vivo to become non-epithelial cell types, and that Ovol2 directly represses key EMT inducers such as Zeb1 and regulates stem/progenitor cell responsiveness to TGF-beta. We also provide evidence for a suppressive role of Ovol2 in breast cancer progression. Our findings underscore the critical importance of exquisitely regulating epithelial plasticity to balance stemness with epithelial differentiation in development and cancer. We report ChIPseq data illustrating Ovol2 genome-wide targets in mouse mammary epithelial cells, suggesting that Ovol2 regulates a plethora of genes associated with the EMT process. Immunoprecipitated samples from HC11 mouse mammary epithelial cells with antibodies against Ovol2 and control IgG respectively were used for ChIP-seq experiments.
Project description:The jmjC-domain containing H3K4 histone demethylase JARID1B/KDM5B/PLU1 is over-expressed in human breast cancer and is a potential target for breast cancer treatment. To investigate the in vivo function of JARID1B, we developed a new strain of Jarid1b knockout mice and characterized the phenotypes in detail. Unlike previously reported knockout strains, the majority of our Jarid1b knockout mice are viable beyond embryonic and neonatal stages. Nonetheless, these mice exhibit decreased body weight, higher incidence of adult mortality and decreased female fertility. Furthermore, Jarid1b knockout mice show delayed mammary gland development. Mechanistically, loss of JARID1B leads to decreased serum estrogen levels and reduced proliferation of mammary epithelial cells in early puberty. In addition, in mammary epithelial cells, loss of JARID1B diminishes the expression of key regulators of mammary morphogenesis, including FOXA1, estrogen receptor α (ERα), and GATA3. Taken together, these results indicate that JARID1B positively regulates mammary ductal development through both extrinsic and cell-autonomous mechanisms. Compare gene expression of Jarid1B Knock Out and Wild type Mammary Epithelial Cells (MECs).
Project description:Triple negative breast cancer (TNBC) has poor prognostic outcome compared to other types of breast cancer1. At present the molecular and cellular mechanisms underlying TNBC pathology are not well understood1. Here we report that the transcription factor BCL11A is overexpressed in TNBC including basal-like breast cancer (BLBC) and that its genomic locus is amplified in up to 38% of BLBC tumours. BCL11A overexpression in immortalised human breast epithelial cells promotes tumour formation in xenograft models, whereas knockdown of BCL11A in TNBC cell lines suppresses their tumourigenic potential. In the DMBA-induced mouse mammary tumour model, Bcl11a is found to be essential for tumourigenesis since deletion of Bcl11a before DMBA treatment substantially decreases tumour formation, even in p53-null cells, and inactivation of Bcl11a in established tumours causes their regression. At the cellular level, BCL11A overexpression enhances clonogenicity in vitro whereas its deletion in the mouse causes a reduction in the number of mammary epithelial stem and progenitor cells. Thus, BCL11A has an important role in the genesis of TNBC and in normal mammary epithelial cells. This study highlights the importance of further investigation of BCL11A in breast cancer diagnosis and targeted therapies. [Mouse] KO is bcl11a deleted mammary stem cells. WT are mammary stem cells with intact Bcl11a. [Human] HMLE tumors overexpressing BCL11A.
Project description:GATA3 is a basic and essential transcription factor that regulates many pathophysiological processes that is required for the development of mammary luminal epithelial cells. Loss-of-function GATA3 alterations in breast cancer are associated with poor prognosis. However, its regulation and function in miRNAs expression has been less explored.
Project description:The receptor tyrosine kinase AXL is associated with epithelial plasticity in several solid tumors including breast cancer and AXL-targeting agents are currently in clinical trials. We hypothesized that AXL is a driver of stemness traits in cancer by co-option of a regulatory function normally reserved for stem cells. AXL-expressing cells in human mammary epithelial ducts co-expressed markers associated with multipotency, and AXL inhibition abolished colony-formation and self-maintenance activities while promoting terminal differentiation in vitro. Axl-null mice did not exhibit a strong developmental phenotype, but enrichment of Axl+ cells was required for mouse mammary gland reconstitution upon transplantation, and Axl-null mice had reduced incidence of Wnt1-driven mammary tumors. An AXL-dependent gene signature is a feature of transcriptomes in basal breast cancers, and reduced patient survival irrespective of subtype. Our interpretation is that AXL regulates access to epithelial plasticity programs in MaSCs and, when coopted, maintains acquired stemness in breast cancer cells.