MITF Expression Predicts Therapeutic Vulnerability to p300 Inhibition in Human Melanoma
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE128737 | GEO | 2020/03/22
REPOSITORIES: GEO
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Project description:Dissection of melanoma heterogeneity through gene expression profiling has led to the identification of two major phenotypes, conventionally defined as “MITF high / proliferative” and “AXL high / invasive”. Tumors or single melanoma cells characterized by a predominant AXL-related gene program show enhanced expression of sets of genes involved in motility, invasion and regulation of epithelial-mesenchymal transition (EMT), while these genes are downregulated in tumors or cells with a predominant MITF-related gene program. The activation of the AXLhi/MITFlo invasive gene program in melanoma is characterized by aberrant expression of transcription factors (TFs) involved in the embryonic EMT process. Additional master genes involved in promoting melanoma growth and invasive state have been identified within the family of epigenetic regulators. Two of these genes, RNF2 and EZH2, components of the polycomb repressive complexes 1 and 2, act by epigenetically silencing tumor suppressors that in turn regulate the invasive and EMT-like phenotype of melanoma cells. Additional master genes involved in promoting melanoma growth and invasive state have been identified within the family of epigenetic regulators. Two of these genes, RNF2 and EZH2, components of the polycomb repressive complexes 1 and 2, act by epigenetically silencing tumor suppressors that in turn regulate the invasive and EMT-like phenotype of melanoma cells. Here we provide evidence for a new actionable pathway that controls melanoma EMT-like/invasive phenotype. We show that in MITFlo melanomas, the TF NFATc2 controls the EMT-like transcriptional program, the invasive ability of neoplastic cells, as well as in-vitro and in-vivo growth, through a pathway that functionally links c-myc to FOXM1 and EZH2. Targeting of NFATc2, FOXM1 or EZH2 inhibited melanoma migratory and invasive activity. Moreover, pharmacological co-targeting of NFATc2 and EZH2 promoted apoptosis of BRAF-mutant melanomas with intrinsic resistance to BRAF inhibition.
2019-02-06 | GSE101323 | GEO
Project description:The transcription factors PAX3 and MITF are required for the development of the neural crest and melanocyte lineage, and both proteins play important roles in melanoma cell growth and survival. PAX3 transcriptionally activates MITF expression during neural crest development, but the relationship between these transcription factors during melanocyte development and in melanoma cells is currently poorly understood. This study aimed to further our understanding of the interaction between transcriptional networks controlled by PAX3 and MITF by assessing the effect of siRNA-mediated knockdown of PAX3 and MITF in metastatic melanoma cell lines. The goals of this study were to determine (i) if PAX3 is required for maintaining expression of MITF in melanoma and melanocyte cell lines; (ii) whether PAX3 and MITF independently, or redundantly, influence growth and survival in melanoma cell lines; and (iii) to investigate the respective roles of PAX3 and MITF expression in melanoma cell differentiation. Microarrays were used to measure global changes in transcript expression in response to siRNA-mediated knockdown of PAX3 or MITF compared to non-targeting controls in two metastatic melanoma cells lines. RNA was isolated from two different metastatic melanoma cell lines 30 hours after one of four different treaments: (i) transfection with siRNA targeting PAX3; or (ii) transfection with siRNA targeting MITF; or (iii) or transfection with siRNA targeting luciferase (non-targeting negative control); or (iv) treatment with media only (control). Therefore, eight samples were used for gene expression profiling by using GeneChip arrays, with one replicate per cell line per treatment.
2010-01-01 | E-GEOD-16249 | biostudies-arrayexpress
Project description:The transcription factors PAX3 and MITF are required for the development of the neural crest and melanocyte lineage, and both proteins play important roles in melanoma cell growth and survival. PAX3 transcriptionally activates MITF expression during neural crest development, but the relationship between these transcription factors during melanocyte development and in melanoma cells is currently poorly understood. This study aimed to further our understanding of the interaction between transcriptional networks controlled by PAX3 and MITF by assessing the effect of siRNA-mediated knockdown of PAX3 and MITF in metastatic melanoma cell lines. The goals of this study were to determine (i) if PAX3 is required for maintaining expression of MITF in melanoma and melanocyte cell lines; (ii) whether PAX3 and MITF independently, or redundantly, influence growth and survival in melanoma cell lines; and (iii) to investigate the respective roles of PAX3 and MITF expression in melanoma cell differentiation. Microarrays were used to measure global changes in transcript expression in response to siRNA-mediated knockdown of PAX3 or MITF compared to non-targeting controls in two metastatic melanoma cells lines.
2010-01-02 | GSE16249 | GEO
Project description:We identified a novel germline mutation of the microphthalmia-associated transcription factor (MITF - E318K). This mutation was found to be present in numerous melanoma families, as well as the general population, where its association with melanoma has a significant effect. We determined the effect of the E318K mutation on global MITF target gene transcription. We developed a tetracycline-inducible system for expression of wild type MITF or the E318K variant in melanoma cell lines with constitutively low or undetectable levels of endogenous MITF (HT144 and C32). We examined whole-genome expression profiles in these cells following induction of either wild-type or E318K MITF for 48 hours. Analysis suggests that the MITF E318K mutant exhibits differential transcriptional activity against some, though not all, target genes. Expression profiling by array
2011-12-01 | E-GEOD-31269 | biostudies-arrayexpress
Project description:Melanoma tumors are highly heterogeneous, comprising of different cell types that vary in their potential for growth and invasion. Heterogeneous expression of the Microphthalmia-associated Transcription Factor (MITF) and the POU domain transcription factor BRN2 (POU3F2) has been found in malignant melanoma. Changing expression of these transcription factors as the disease progresses has been linked to the metastatic mechanism of phenotype switching. We therefore investigated the effects of MITF and BRN2 expression in melanoma growth and metastasis. Depletion of MITF resulted in a cell population that had a slowed cell cycle progression, was less invasive in vitro and had hindered tumor and metastasis forming ability in mouse xenograft studies. BRN2 depletion left a cell population with intact proliferation and invasion in vitro; however metastatic growth was significantly reduced in the mouse xenograft model. These results suggest that the proliferative population within melanoma tumors express MITF, and both MITF and BRN2 are important for metastatic growth in vivo. This finding highlights the importance of BRN2 and MITF expression in development of melanoma metastasis.
2017-08-16 | GSE101434 | GEO
Project description:Somatic oncogenic mutation of BRAF coupled with inactivation of PTEN constitute a frequent combination of genomic alterations driving development of human melanoma. Mice genetically engineered to conditionally express oncogenic BrafV600E and inactivate Pten in melanocytes following tamoxifen treatment rapidly develop melanoma. While early stage melanomas comprised melanin-pigmented Mitf and Dct-expressing cells, expression of these and other melanocyte identity genes was lost in later stage tumours that showed histological and molecular characteristics of de-differentiated neural crest type cells. Melanocyte identity genes displayed loss of active chromatin marks and RNA polymerase II and gain of heterochromatin marks indicating epigenetic reprogramming during tumour progression. Nevertheless, late stage tumour cells grown in culture re-expressed Mitf and melanocyte markers and Mitf together with Sox10 co-regulated a large number of genes essential for their growth. In this melanoma model, somatic inactivation that the catalytic Brg1 (Smarca4) subunit of the SWI/SNF complex and the scaffolding Bptf subunit of the NuRF delayed tumour formation and deregulated large and overlapping gene expression programs essential for normal tumour cell growth. Moreover, we show that Brg1 and Bptf co-regulated many genes together with Mitf and Sox10. Together these transcription factors and chromatin remodelling complexes orchestrate essential gene expression programs in mouse melanoma cells
2019-04-17 | GSE100998 | GEO
Project description:A recent study of the characteristics of coexisting melanoma and renal cell carcinoma RCC in the same patients supports a genetic predisposition underlying the association between these two cancers. The microphthalmia associated transcription factor (MITF) was proposed to act as a melanoma oncogene; it also stimulates the transcription of hypoxia inducible factor (HIF1A), whose pathway is targeted by kidney cancer susceptibility genes. By sequencing the MITF gene, we detected a germ line missense substitution (p.E318K) in 5 of 62 patients affected with melanoma and RCC. When compared with 1,659 controls, this MITF substitution occurred at a significantly higher frequency in melanoma + RCC patients (p = 1.3x10-4), melanoma -only patients (p = 7.8 x10-5), and RCC-only patients (p = 0.008). Overall, p.E318K substitution carriers had a higher than fivefold increased risk of developing melanoma, RCC or both cancers (odds-ratio = 5.55, 95% confidence interval = 2.59 to 12.91). Codon 318 falls in the second MITF-conserved, small-ubiquitin like modifier (SUMO)-1 consensus binding site (YKXE) and the p.E318K substitution severely impairs SUMOylation of MITF. MITF p.E318K binds more efficiently to the HIF1A promoter and increases its activation compared to the wild type MITF. In RCC cell line, transcriptomic approach identifies a MITF p.E318K signature related to cell growth, proliferation and inflammation. MITF p.E318K is more potent than wild type MITF in promoting melanocytic and renal cell clonogenicity, migration and invasion, consistent with a gain-of-function role in tumorigenesis. Our data provide novel insights on the link between transcription, sumoylation and cancer, possibly mediated by oxidative stress. This set of 26 arrays presents expression data for 3 conditions (reference cell line, with addition of wt MITF or e318K MITF for two different cell lines (melanoma A375 and renal RCC4), in dye swap and 3 independant biological replicates.
2011-09-03 | E-TABM-1198 | biostudies-arrayexpress
Project description:We identified a novel germline mutation of the microphthalmia-associated transcription factor (MITF - E318K). This mutation was found to be present in numerous melanoma families, as well as the general population, where its association with melanoma has a significant effect. We determined the effect of the E318K mutation on global MITF target gene transcription. We developed a tetracycline-inducible system for expression of wild type MITF or the E318K variant in melanoma cell lines with constitutively low or undetectable levels of endogenous MITF (HT144 and C32). We examined whole-genome expression profiles in these cells following induction of either wild-type or E318K MITF for 48 hours. Analysis suggests that the MITF E318K mutant exhibits differential transcriptional activity against some, though not all, target genes.
2011-12-01 | GSE31269 | GEO
Project description:Epigenetic events, including covalent post-translational modification of histones, have frequently been demonstrated to play critical roles in tumor development and progression. The transcriptional coactivator, p300/CBP, possesses both histone acetyltransferase (HAT) activity as well as scaffolding properties that directly influence transcriptional activation of targeted genes. We have used a recently reported small molecule inhibitor of p300 HAT activity, C646, to explore the specific contribution of p300/CBP HAT activity to tumor development and progression. We find that C646 inhibits the growth of lineage-specific tumor cell lines including human melanomas through direct transcriptional regulation of cell cycle regulatory proteins. Further evaluation of the p300 HAT transcriptome in human melanoma cells using comprehensive gene expression profiling reveals that p300 HAT activity globally promotes cell cycle progression, nucleosome assembly, and the DNA damage checkpoint through direct transcriptional regulatory mechanisms. Additionally, C646 promotes sensitivity to DNA damaging agents leading to enhanced apoptosis of melanoma cells following combination treatment with cisplatin. Together our data suggest that p300 HAT activity regulates critical growth regulatory pathways in tumors and may serve as a novel therapeutic target for melanoma and other malignancies by promoting cellular responses to DNA damaging agents. Keywords: p300, small molecule inhibitor, melanoma WM35 cells grown under normal culture conditions were treated for 6 and 24 hours with compound C646 to block p300 HAT activity. A vehicle control (DMSO) was included at each time point. RNA was extracted from all 4 samples using the Qiagen RNeasy kit. RNA quality check, labeling, hybridization, initial data processing and analysis was performed by the JHMI Microarray Core Facility. Affymetrix GeneChip Human Exon 1.0 ST Array was used for this study.
2013-08-01 | E-GEOD-45981 | biostudies-arrayexpress
Project description:Phenotypic and metabolic heterogeneity within tumors is a major barrier to effective cancer therapy. Yet how metabolism is implicated in specific phenotypes, and whether lineage-restricted mechanisms control key metabolic vulnerabilities remains poorly understood. In melanoma, down-regulation of the lineage addiction oncogene Microphthalmia-associated Transcription Factor (MITF) is a hallmark of the proliferative-to-invasive phenotype switch, though how MITF promotes proliferation and suppresses invasion is poorly defined. Here we show that MITF is a lineage restricted activator of the key lipogenic enzyme stearoyl-CoA desaturase (SCD), and that SCD is required for MITFHigh melanoma cell proliferation. By contrast MITFLow cells are insensitive to SCD inhibition. Significantly, the MITF-SCD axis suppresses metastasis, inflammatory signalling, and an ATF4-mediated feedback-loop that maintains dedifferentiation. Our results reveal that MITF is a lineagespecific regulator of metabolic reprogramming, whereby fatty acid composition is a driver of melanoma phenotype-switching, and highlight that cell phenotype dictates response to drugs targeting lipid metabolism.
2019-10-16 | GSE137390 | GEO