Project description:To analyze the effects of Cdh1 signaling on melanoma properties, we performed microarray analysis to identify genes induced by soluble Cdh1 in mouse melanoma cell line B16-F10.
Project description:Objective was to uncover the transcriptional changes occuring in melanoma-associated LECs relative to LECs of naïve skin. To investigate the transcriptional changes in LECs during tumor development, RNA was extracted from LECs sorted from naïve skin and BPC (Tyr::Cre-ER, BRafV600E) murine melanomas and bulk RNA-seq performed. Naïve skin LECs were collected from 3 mice and tumor-associated LECs collected from 4 mice.
Project description:Expression profiles of 17 melanoma cell lines were analysed to identify genes differentially expressed between cell lines harbouring wild-type or mutant p16INK4A. Relevant paper: Pavey et al. (2007). Note: all of these cell lines contained wild-type p14ARF, so that the transcriptional effects of p16INk4A could be determined without interference from p14ARF. Experiment Overall Design: The aim of this study was to identify genes which are transcriptional targets of p16INK4A in melanoma.
Project description:Melanomas are heterogeneous and adopt multiple transcriptional states that can confer an invasive phenotype and resistance to therapy. Little is known about the epigenetic drivers of these cell states, limiting our ability to regulate melanoma heterogeneity and tumor progression. Here we identify stress-induced HDAC8 activity as the driver of a transcriptional state that increased the formation of melanoma brain metastases (MBM). Exposure of melanocytes and melanoma cells to multiple different stresses led to HDAC8 activation, a switch to a gene expression signature associated with a neural crest-stem cell like state (NCSC) and the adoption of an amoeboid, invasive phenotype. This cell state enhanced the survival of melanoma cells under shear stress conditions and increased the formation of metastases in the brain. ATAC-Seq and ChIP-Seq analysis showed HDAC8 to alter chromatin structure by increasing H3K27ac and accessibility at c-Jun binding sites without changing global histone acetylation. The increased accessibility of Jun binding sites was paralleled by decreased H3K27ac and accessibility at MITF binding sites and loss of melanoma-lineage gene expression. Mass spectrometry-based acetylomics demonstrated that HDAC8 deacetylated the histone acetyltransferase (HAT) EP300 leading to its enzymatic inactivation. This, in turn, led to an increased binding of EP300 to Jun-transcriptional sites and decreased binding to MITF-transcriptional sites. Increased expression of EP300 decreased invasion and increased the sensitivity of melanoma cells to multiple stresses while inhibition of EP300 function increased invasion, resistance to stress and the development of MBM. We identified HDAC8 as a novel mediator of transcriptional co-factor inactivation and chromatin accessibility that increases MBM development.
Project description:RATIONALE: Identification of genes that may be associated with developing certain types of cancer may someday provide important information about a person’s risk of getting cancer.
PURPOSE: This clinical trial is studying to see if certain genes may be associated with cancer in patients with cancer of the breast, prostate, lung, or colon and siblings of these patients.
Project description:Cellular stress contributes to the capacity of melanoma cells to undergo phenotype switching into highly migratory and drug tolerant dedifferentiated states. Such dedifferentiated melanoma cell states are marked by loss of melanocyte specific gene expression and increase of mesenchymal markers. Two crucial transcription factors, MITF and SOX10, important in melanoma development and progression have been implicated in this process. In this study we describe that loss of MITF is associated with a distinct transcriptional program, MITF promoter hypermethylation and poor patient survival in metastatic melanoma. From a comprehensive collection of melanoma cell lines, we observed that MITF methylated cultures were subdivided in two distinct subtypes. Examining mRNA levels of neural crest associated genes we found that one subtype had lost the expression of several lineage genes including SOX10. Intriguingly, SOX10 loss was associated with SOX10 gene promoter hypermethylation and distinct phenotypic and metastatic properties. Depletion of SOX10 in MITF methylated melanoma cells using CRISPR/Cas9 confirmed these findings. In conclusion, this study describes the significance of melanoma state and the underlying functional properties explaining the aggressiveness of such states.
Project description:Transcriptional addiction of cancer cells for Super-Enhancer (SE) associated genes has been proven through an extensive use of transcriptional inhibitors against specific co-activators toward which SE are esponentially dependent compared to canonical enhancers. However, each cancer type displays different sensitivity against this new class of drugs whose efficacy may vary according to their transcriptomic profile including the expression of enzymatic proteins able to confer intrinsic tolerance or resistance. Moreover, SE has been observed as well in healthy cells which point a realistic concern toward the specificity of transcriptional inhibitors and their side effects on healthy tissues. Therefore, we looked at SE-associated genes specific for cancer using melanoma as a model. Here, we identified BAHCC1 whose activity is higher in melanoma compare to other cancer types and normal tissues. BAHCC1 is a protein involved both in gene expression and genomic stability. To explore BAHCC1 role in gene expression, we performed functional studies in melanoma cells in basal conditions or upon BAHCC1 silencing. Strikingly, BAHCC1 regulates an E2F-dependent subset of genes together with SWI/SNF chromatin remodelling complex.
Project description:Transcriptional addiction of cancer cells for Super-Enhancer (SE) associated genes has been proven through an extensive use of transcriptional inhibitors against specific co-activators toward which SE are esponentially dependent compared to canonical enhancers. However, each cancer type displays different sensitivity against this new class of drugs whose efficacy may vary according to their transcriptomic profile including the expression of enzymatic proteins able to confer intrinsic tolerance or resistance. Moreover, SE has been observed as well in healthy cells which point a realistic concern toward the specificity of transcriptional inhibitors and their side effects on healthy tissues. Therefore, we looked at SE-associated genes specific for cancer using melanoma as a model. Here, we identified BAHCC1 whose activity is higher in melanoma compare to other cancer types and normal tissues. BAHCC1 is a protein involved both in gene expression and genomic stability. To explore BAHCC1 role in gene expression, we performed functional studies in melanoma cells in basal conditions or upon BAHCC1 silencing. Strikingly, BAHCC1 regulates an E2F-dependent subset of genes together with SWI/SNF chromatin remodelling complex.