Landscape of enhancer disruption and functional screen in melanoma
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE210424 | GEO | 2023/10/10
REPOSITORIES: GEO
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Project description:The high mutation rate across the whole melanoma genome provides a major challenge in stratifying true driver events from the background mutations. Many non-coding recurrent events, such as those occurred in enhancer, can shape tumor evolution, emphasizing the importance in systematically deciphering enhancer disruptions in melanoma. Here, we leveraged 297 melanoma whole-genome sequencing (WGS) samples to prioritize highly recurrent regions (HRRs). By performing a genome-scale CRISPR interference (CRISPRi) screen on HRR-associated enhancers in melanoma cells, we identified 66 significant hits which could have tumor-suppressive roles. These functional enhancers show unique mutational patterns independent of classical significantly mutated genes in melanoma. Target gene analysis for the essential enhancers revealed many known and hidden mechanisms underlying melanoma development. We demonstrated that a super enhancer element could modulate melanoma cell proliferation by targeting MEF2A and another distal enhancer was able to sustain PTEN tumor-suppressive potential via long-range interaction. Our study established a catalogue of crucial enhancers and their target genes in melanoma development and progression, which illuminates the identification of novel mechanism of dysregulation for melanoma driver genes and new therapeutic targeting strategy.
2023-10-11 | GSE210423 | GEO
Project description:The high mutation rate across the whole melanoma genome provides a major challenge in stratifying true driver events from the background mutations. Many non-coding recurrent events, such as those occurred in enhancer, can shape tumor evolution, emphasizing the importance in systematically deciphering enhancer disruptions in melanoma. Here, we leveraged 297 melanoma whole-genome sequencing (WGS) samples to prioritize highly recurrent regions (HRRs). By performing a genome-scale CRISPR interference (CRISPRi) screen on HRR-associated enhancers in melanoma cells, we identified 66 significant hits which could have tumor-suppressive roles. These functional enhancers show unique mutational patterns independent of classical significantly mutated genes in melanoma. Target gene analysis for the essential enhancers revealed many known and hidden mechanisms underlying melanoma development. We demonstrated that a super enhancer element could modulate melanoma cell proliferation by targeting MEF2A and another distal enhancer was able to sustain PTEN tumor-suppressive potential via long-range interaction. Our study established a catalogue of crucial enhancers and their target genes in melanoma development and progression, which illuminates the identification of novel mechanism of dysregulation for melanoma driver genes and new therapeutic targeting strategy.
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Project description:The high mutation rate across the whole melanoma genome provides a major challenge in stratifying true driver events from the background mutations. Many non-coding recurrent events, such as those occurred in enhancer, can shape tumor evolution, emphasizing the importance in systematically deciphering enhancer disruptions in melanoma. Here, we leveraged 297 melanoma whole-genome sequencing (WGS) samples to prioritize highly recurrent regions (HRRs). By performing a genome-scale CRISPR interference (CRISPRi) screen on HRR-associated enhancers in melanoma cells, we identified 66 significant hits which could have tumor-suppressive roles. These functional enhancers show unique mutational patterns independent of classical significantly mutated genes in melanoma. Target gene analysis for the essential enhancers revealed many known and hidden mechanisms underlying melanoma development. We demonstrated that a super enhancer element could modulate melanoma cell proliferation by targeting MEF2A and another distal enhancer was able to sustain PTEN tumor-suppressive potential via long-range interaction. Our study established a catalogue of crucial enhancers and their target genes in melanoma development and progression, which illuminates the identification of novel mechanism of dysregulation for melanoma driver genes and new therapeutic targeting strategy.
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Project description:Myocyte Enhancer Factor 2 (MEF2) proteins are involved in multiple developmental, physiological, and pathological processes in vertebrates. Protein:protein interactions underlie the plethora of biological processes impacted by MEF2A, necessitating a detailed characterization of the MEF2A interactome. A nanobody based affinity-purification/mass spectrometry strategy was employed to achieve this goal. Specifically, the MEF2A protein complexes were captured from myogenic lysates using a GFP-tagged MEF2A protein immobilized with a GBP-nanobody followed by LC-MS/MS proteomic analysis to identify MEF2A interactors.
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Project description:Here, we combine comparative regulatory genomics with machine learning to investigate enhancer logic in melanoma. Through epigenomics profiling of 26 melanoma cell lines across six species, we examine the conservation of the two main melanoma states and underlying master regulators. By training a deep neural network on topic models derived from the human lines, we were able to classify not only human melanoma enhancers, but also regulatory regions in the other species. The deep learning model revealed important genomic features (i.e. TF binding motifs) for the different melanoma states, how they co-occur within melanoma enhancers, and where they are placed with respect to the central enhancer nucleosome. This in-depth analysis of the melanoma enhancer code allowed us to propose a mechanistic model of TF binding in MEL melanoma enhancers. Finally, by exploiting the deep layers of our model, we are able to identify causal mutations for melanoma enhancer loss and gain through evolution, not only affecting enhancer accessibility but also activity.
2020-04-22 | GSE142238 | GEO
Project description:Enhancers play key roles in gene regulation. However, comprehensive enhancer discovery is challenging because most enhancers, especially those affected in complex diseases, have weak effects on gene expression. Through gene regulatory network modeling, we identified that dynamic cell state transitions, a critical missing component in prevalent enhancer discovery strategies, can be utilized to improve the cells’ sensitivity to enhancer perturbation. Guided by the modeling results, we performed a mid-transition CRISPRi-based enhancer screen utilizing human embryonic stem cell definitive endoderm differentiation as a dynamic transition system. The screen discovered a comprehensive set of enhancers (4 to 9 per locus) for each of the core lineage-specifying transcription factors (TFs), including many enhancers with weak to moderate effects. Integrating the screening results with enhancer activity measurements (ATAC-seq, H3K27ac ChIP-seq) and three-dimensional enhancer-promoter interaction information (CTCF looping, Hi-C), we were able to develop a CTCF loop-constrained Interaction Activity (CIA) model that can better predict functional enhancers compared to models that rely on Hi-C-based enhancer-promoter contact frequency. Together, our dynamic network-guided enhancer screen and the CIA enhancer prediction model provide generalizable strategies for sensitive and more comprehensive enhancer discovery in both normal and pathological cell state transitions.
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Project description:Using human aortic enhancers to prioritize genomic regions for GWAS analysis
2016-10-30 | E-MTAB-4935 | biostudies-arrayexpress
Project description:Thousands of enhancers are characterized in the human genome, yet few have been shown important in cancer. Inhibiting oncokinases, such as EGFR, ALK, HER2, and BRAF, is a mainstay of current cancer therapy but is hindered by innate drug resistance mediated by upregulation of the HGF receptor, MET. The mechanisms mediating such genomic responses to targeted therapy are unknown. Here, we identify lineage-specific MET enhancers for multiple common tumor types, including a melanoma lineage-specific MET enhancer that displays inducible chromatin looping and MET gene induction upon BRAF inhibition. Epigenomic analysis demonstrated that the melanocyte-specific transcription factor, MITF, mediates this enhancer function. Targeted genomic deletion (<7bp) of the MITF motif within the MET enhancer suppressed inducible chromatin looping and innate drug resistance, while maintaining MITF-dependent, inhibitor-induced melanoma cell differentiation. Epigenomic analysis can thus guide functional disruption of regulatory DNA to decouple pro- and anti-oncogenic functions of tumor lineage-enriched transcription factors mediating innate resistance to oncokinase therapy. COLO829 human melanoma cell line harboring the BRAFV600E mutation was treated with BRAF inhibtior PLX4032 (Vemurafenib) and/or a hairpin against MITF
2014-01-14 | E-GEOD-50649 | biostudies-arrayexpress
Project description:Thousands of enhancers are characterized in the human genome, yet few have been shown important in cancer. Inhibiting oncokinases, such as EGFR, ALK, HER2, and BRAF, is a mainstay of current cancer therapy but is hindered by innate drug resistance mediated by upregulation of the HGF receptor, MET. The mechanisms mediating such genomic responses to targeted therapy are unknown. Here, we identify lineage-specific MET enhancers for multiple common tumor types, including a melanoma lineage-specific MET enhancer that displays inducible chromatin looping and MET gene induction upon BRAF inhibition. Epigenomic analysis demonstrated that the melanocyte-specific transcription factor, MITF, mediates this enhancer function. Targeted genomic deletion (<7bp) of the MITF motif within the MET enhancer suppressed inducible chromatin looping and innate drug resistance, while maintaining MITF-dependent, inhibitor-induced melanoma cell differentiation. Epigenomic analysis can thus guide functional disruption of regulatory DNA to decouple pro- and anti-oncogenic functions of tumor lineage-enriched transcription factors mediating innate resistance to oncokinase therapy. MITF ChIP-seq was performed in primary human melanocytes with overexpression of BRAFV600E or a lentiviral control (RFP), and in COLO829 melanoma cells treated with DMSO, or PLX4032
2014-01-14 | E-GEOD-50681 | biostudies-arrayexpress