Project description:Neuroendocrine prostate cancer (NEPC) is a rare but aggressive histologic variant of prostate cancer that responds poorly to androgen deprivation therapy. Hybrid NEPC-adenocarcinoma (AdCa) tumors are common, often eluding accurate pathologic diagnosis and requiring ancillary markers for classification. We recently performed an outlier-based meta-analysis across a number of independent gene expression microarray datasets to identify novel markers that differentiate NEPC from AdCa, including up-regulation of Insulinoma-associated protein 1 (INSM1) and loss of Yes-associated protein 1 (YAP1). Here, using diverse cancer gene expression datasets, we show that Hippo pathway-related genes, including YAP1, are among the top down-regulated gene sets with expression of the neuroendocrine transcription factors, including INSM1. In prostate cancer cell lines, transgenic mouse models and human prostate tumor cohorts, we confirm that YAP1 RNA and YAP1 protein expression are silenced in NEPC and demonstrate that the inverse correlation of INSM1 and YAP1 expression helps to distinguish AdCa from NEPC. Mechanistically, we find that YAP1 loss in NEPC may help to maintain INSM1 expression in prostate cancer cell lines and we further demonstrate that YAP1 silencing likely occurs epigenetically, via CpG hypermethylation near its transcriptional start site. Taken together, these data nominate two additional markers to distinguish NEPC from AdCa and add to data from other tumor types suggesting that Hippo signaling is tightly reciprocally regulated with neuroendocrine transcription factor expression.
Project description:Merkel Cell carcinoma (MCC) is an aggressive neuroendocrine skin cancer often driven by Merkel cell polyomavirus T antigens. The epigenomic mechanisms driving MCC are poorly understood. We show that virus positive MCC (VP-MCC) super enhancer networks are committed to and controlled by lineage-specific neuroendocrine transcription factors (TFs) including LHX3, ISL1, ATOH1, INSM1, SOX2 and POU4F3. These VP-MCC TFs are central to core regulatory (CR) transcriptional circuitry, essential for growth, and co-bind enhancers with polyomavirus small T antigen. We establish that T antigen expression is directly regulated by LHX3 and ISL1, establishing a positive feedback autoregulatory circuitry for a neuroendocrine state.
Project description:We analyzed the expression profiles of human and mouse meningiomas (driven by NF2 loss, YAP1-MAML2, TRAF7/KLF4/SMO1/AKT1, or constitutively active non-fusion YAP1). We found that YAP1-MAML2 meningiomas resemble NF2mutant tumors and constitutively exert de-regulated YAP1 activity that is dependent on the interaction with TEADs.
Project description:We analyzed the expression profiles of human and mouse meningiomas (driven by NF2 loss, YAP1-MAML2, TRAF7/KLF4/SMO1/AKT1, or constitutively active non-fusion YAP1). We found that YAP1-MAML2 meningiomas resemble NF2mutant tumors and constitutively exert de-regulated YAP1 activity that is dependent on the interaction with TEADs.
Project description:In order to define YAP1-specific gene expression patterns in gastric cancer, the constitutively active mutant YAP1 (YAP1-S127A) was over-expressed in MKN45 gastric cancer cells. Defined gene expression signature was later used to stratify gastric cancer patients according to the presence of the YAP1-activated signature. Three groups of samples are included: 1. Mock control; 2. Vector control; 3. YAP-S127A expression. Gene expression profiles of YAP-S127A mutant-expressing cells were compared to that of mock and vector control. Experiments were done in MKN45 gastric cancer cells.
Project description:Doxycycline-inducible YAP1 S127A-driven rhabdomyosarcoma (RMS) tumors, control skeletal muscle and regressed tumors following YAP1 normalization by doxycycline withdrawal were compared to determine the YAP1-regulated gene expression profile relevant to RMS formation. To characterize the role of YAP1 in embryonal RMS at the molecular level and identify a gene signature for YAP1 activity readout, we compared the gene expression profiles of our YAP1-driven ERMS with control donor skeletal muscle (SKM) and doxycycline-withdrawn regressing tumors by microarray (doxycycline withdrawal for 3 or 6 days; OFF3 and OFF6, respectively). We next extracted a list of genes regulated by YAP1 in our YAP1-driven ERMS tumors (TUM) versus the 3 other conditions: skeletal muscle control (SKM), Doxycycline-withdrawn 3 days (OFF3) and 6 days (OFF6). The overlap between the 3 lists identified a subset of 633 common upregulated genes, named the YAP1-ERMS_UP signature, as well as 249 common downregulated genes, termed the YAP1-ERMS_DOWN signature. Proliferative pathways and transcriptional targets of E2F factors were highlighted in the YAP1-ERMS_UP genes, while muscle differentiation and trancriptional targets of myogenic factors Myod1 and Mef2 were highlighted in the YAP1-ERMS_DOWN genes. Tumor regression conditions (OFF3 days; OFF6 days) as well as control muscle (CTL) were compared with tumors at day 0 of doxycycline withdrawal (TUM). 3 samples for each conditions were used.
Project description:Yap1 is a critical transcription coactivator in the Hippo pathways. However, its target genes are not well defined in prostate cancer cells. To determine the downstream transcriptional targets and pathways of Yap1 in Pten/Smad4-defiicent mouse prostate cancer cells, ChIP-seq was performed in the Pten/Smad4-deficient mouse prostate cancer cells.