Overexpression of HDAC8 establishes a unique gene signature in BRAF-mutant melanoma cells
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE127564 | GEO | 2019/04/15
REPOSITORIES: GEO
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Project description:Melanoma cells are highly plastic and have the ability to switch to a dedifferentiated, invasive phenotype in response to multiple stimuli. Here, we show that exposure of melanoma cell lines and patient specimens to multiple stresses including BRAF-MEK inhibitor therapy, hypoxia and UV-irradiation leads to an increase in histone deacetylase 8 (HDAC8) expression/activity, and in turn, the adoption of a drug-resistant, invasive phenotype. Systems level analyses using mass spectrometry-based phosphoproteomics implicated HDAC8 in the regulation of MAPK and AP-1 signaling pathways. Introduction of HDAC8 into drug-naïve melanoma cells conveyed resistance both in vitro and in in vivo xenograft models. HDAC8-mediated BRAF inhibitor resistance was mediated via receptor tyrosine kinase (RTK) activation leading to Ras/CRAF/MEK/ERK signaling. Although HDACs primarily function at the histone level, they also regulate signaling through the modulation of non-histone substrates. In line with this, HDAC8 introduction decreased the acetylation of c-Jun, increasing its transcriptional activity and enriching for an AP-1 gene signature. Mutation of the putative c-Jun acetylation site at lysine residue 273 reduced the transcriptional activation of c-Jun in melanoma cells and conveyed resistance to BRAF inhibition through increased RTK expression and enhanced MAPK pathway activity. In vivo xenograft studies confirmed the key role of HDAC8 in therapeutic adaptation, with both non-selective and HDAC8-specific inhibitors enhancing the durability of response to BRAF inhibitor therapy. Our studies demonstrate that HDAC8-specific inhibitors could represent an excellent strategy to limit the adaptation of melanoma cells to multiple stresses and therapeutic interventions, including BRAF-MEK inhibitor combinations.
2020-07-07 | PXD012812 | Pride
Project description:Melanoma cells are highly plastic and have the ability to switch to a dedifferentiated, invasive phenotype in response to multiple stimuli. Here, we show that exposure of melanoma cell lines and patient specimens to multiple stresses including BRAF-MEK inhibitor therapy, hypoxia and UV-irradiation leads to an increase in histone deacetylase 8 (HDAC8) expression/activity, and in turn, the adoption of a drug-resistant, invasive phenotype. Systems level analyses using mass spectrometry-based phosphoproteomics implicated HDAC8 in the regulation of MAPK and AP-1 signaling pathways. Introduction of HDAC8 into drug-naïve melanoma cells conveyed resistance both in vitro and in in vivo xenograft models. HDAC8-mediated BRAF inhibitor resistance was mediated via receptor tyrosine kinase (RTK) activation leading to Ras/CRAF/MEK/ERK signaling. Although HDACs primarily function at the histone level, they also regulate signaling through the modulation of non-histone substrates. In line with this, HDAC8 introduction decreased the acetylation of c-Jun, increasing its transcriptional activity and enriching for an AP-1 gene signature. Mutation of the putative c-Jun acetylation site at lysine residue 273 reduced the transcriptional activation of c-Jun in melanoma cells and conveyed resistance to BRAF inhibition through increased RTK expression and enhanced MAPK pathway activity. In vivo xenograft studies confirmed the key role of HDAC8 in therapeutic adaptation, with both non-selective and HDAC8-specific inhibitors enhancing the durability of response to BRAF inhibitor therapy. Our studies demonstrate that HDAC8-specific inhibitors could represent an excellent strategy to limit the adaptation of melanoma cells to multiple stresses and therapeutic interventions, including BRAF-MEK inhibitor combinations.
2020-07-07 | PXD012813 | Pride
Project description:HDAC8 expression is causative for resistance to BRAF inhibiton and increased migration in BRAF mutant melanoma cell lines. Changes in gene expression were determined upon forced HDAC8 expression in an isogenic cell line.
2023-09-26 | GSE240307 | GEO
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.
2023-09-26 | PXD044471 | Pride
Project description:Expression data from MDA-MB231 human breast cancer cells treated with metalloproteinase inhibitor (10uM BB94), MEK inhibitor (3uM PD325901), or DMSO control shows substantial overlap in the transcriptional responses arising from MEK and protease inhibition, suggesting a shared mechanism of action. Kinase inhibitor resistance often involves upregulation of poorly understood “bypass” signaling pathways. Here, we show that extracellular proteomic adaptation is one path to bypass signaling and drug resistance. Proteolytic shedding of surface receptors, which can provide negative feedback on signaling activity, is blocked by kinase inhibitor treatment and enhances bypass signaling. In particular, MEK inhibition broadly decreases shedding of multiple receptor tyrosine kinases (RTKs) including HER4, MET, and most prominently AXL, an ADAM10 and ADAM17 substrate, thus increasing surface RTK levels and mitogenic signaling. Progression-free survival of melanoma patients treated with clinical BRAF/MEK inhibitors inversely correlates with RTK shedding reduction following treatment, as measured non-invasively in blood plasma. Disrupting protease inhibition by neutralizing TIMP1 improves MAPK inhibitor efficacy, and combined MAPK/AXL inhibition synergistically reduces tumor growth and metastasis in xenograft models. Altogether, extracellular proteomic rewiring through reduced RTK shedding represents a surprising mechanism for bypass signaling in cancer drug resistance.
2016-03-21 | GSE77868 | GEO
Project description:Fifty percent of cutaneous melanomas are driven by activated BRAFV600E, but tumors treated with RAF inhibitors, even when they respond dramatically, rapidly adapt and develop resistance. Thus, there is a pressing need to identify the major mechanisms of intrinsic and adaptive resistance and develop drug combinations that target these resistance mechanisms. In a combinatorial drug screen on a panel of 12 treatment-naïve BRAFV600E mutant melanoma cell lines of varying levels of resistance to MAPK pathway inhibition we identified the combination PLX4720, a targeted inhibitor of mutated BRaf, and lapatinib, an inhibitor of the ERBB family of receptor tyrosine kinases, as synergistically cytotoxic in the subset of cell lines that displayed the most resistance to PLX4720. To identify potential mechanisms of resistance to PLX4720 treatment and synergy with lapatinib treatment we performed a multi-platform functional genomics analysis to profile the genome as well as the transcriptional and proteomic responses of these cell lines to treatment with PLX4720. We found modest levels of resistance correlated with the zygosity of the BRAF V600E allele and RTK mutational status. Layered over base-line resistance was substantial upregulation of many ERBB pathway genes in response to BRaf inhibition, thus generating the vulnerability to combination with lapatinib. The transcriptional responses of ERBB pathway genes are associated with a number of transcription factors, including ETS2 and its associated cofactors that represent a convergent regulatory mechanism conferring synergistic drug susceptibility in the context of diverse mutational landscapes. 12 BRAF mutant melanomas and 4 melanomas with WT BRAF were exposed plx4720 treatment to evaluate their responses after 8 hours of treatment. 5 of the 12 BRAF mutant melanomas responses were also evaluated in response to the treatment of lapatinib alone, masitinib alone, the combination of lapatinib with plx4720, or the combination of masitinib with plx4720. All samples were run in at least triplicate.
2015-09-16 | E-GEOD-68453 | biostudies-arrayexpress
Project description:Fusion genes can be oncogenic drivers in a variety of cancer types and represent potential targets for targeted therapy. The BRAF gene is frequently involved in oncogenic fusions, with fusion frequencies of 0.2-3% throughout different cancers. However, BRAF fusions rarely occur in the same gene configuration, potentially challenging personalized therapy design. In particular, the influence that is imposed by the wide variety of fusion partners on the oncogenic role of BRAF during tumor growth and drug response is unknown. Here, we used patient-derived colorectal cancer organoids to functionally characterize and cross-compare previously identified BRAF fusions containing various partner genes (AGAP3, DLG1 and TRIM24) with respect to cellular behaviour, downstream signaling activation and response to targeted therapies. We demonstrate that 5’ partner choice of BRAF fusions affects their subcellular localization and intracellular signaling capacity. In particular the DLG1-BRAF fusion protein showed distinct localization to the plasma membrane and exhibited increased activation of downstream MAPK signaling under unperturbed conditions. Moreover, phosphoproteomics and RNA sequencing identified distinct subsets of affected signaling pathways and altered gene expression of BRAF fusions. The different BRAF fusions exhibited varying sensitivities to simultaneous targeted inhibition of MEK and the EGF receptor family. However, all BRAF fusions conveyed resistance to targeted monotherapy against the EGF receptor family, suggesting that BRAF fusions should be screened alongside other MAPK pathway alterations to identify mCRC patients to exclude from cetuximab treatment
2020-01-16 | PXD013461 | Pride
Project description:Rapid resistance to BRAF inhibitors in BRAFV600-mutant metastatic melanoma has produced an urgent need for new treatment options. BRAF inhibitor resistance commonly involves reactivation of mitogen-activated protein kinase (MAPK) signaling and yet inhibition of downstream kinases has not circumvented resistance, partly because MAPK is regulated via a complex network of feedback mechanisms that influence pathway rebound. To examine the transcriptome responses of melanoma cells to MAPK inhibition, a panel of 11 BRAFV600-mutant melanoma cell lines were treated with control (DMSO), 100nM dabrafenib alone (i.e BRAF inhibitor monotherapy) or 100nM dabrafenib + 10nM trametinib (i.e combination BRAF + MEK inhibition) for 24h.
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Project description:HDAC8, a member of class I HDACs, plays a pivotal role in cell cycle regulation by deacetylating the cohesin subunit SMC3. While cyclins and CDKs are well-established cell cycle regulators, our knowledge of other regulators remains limited. Here we reveal the acetylation of K202 in HDAC8 as a key cell cycle regulator responsive to stress. K202 acetylation in HDAC8, primarily catalyzed by Tip60, restricts HDAC8 activity, leading to increased SMC3 acetylation and cell cycle arrest. Furthermore, cells expressing the mutant form of HDAC8 mimicking K202 acetylation display significant alterations in gene expression, potentially linked to changes in 3D genome structure, including enhanced chromatid loop interactions. K202 acetylation impairs cell cycle progression by disrupting the expression of cell cycle-related genes and sister chromatid cohesion, resulting in G2/M phase arrest. These findings indicate the reversible acetylation of HDAC8 as a cell cycle regulator, expanding our understanding of stress-responsive cell cycle dynamics.
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Project description:Acquired BRAF/MEK inhibitor resistance in melanoma results in a new transcriptional state associated with increased risk of metastasis. Here, we identified non-canonical EphA2 signaling as a driver of the resistance-associated metastatic state. We used mass spectrometry-based proteomic and phenotypic assays to demonstrate that the expression of active non-canonical EphA2-S897E in melanoma cells led to a mesenchymal-to-amoeboid transition (MAT) driven by Cdc42 activation. The induction of MAT promoted melanoma cell invasion, survival under shear stress, adhesion to endothelial cells under continuous flow conditions, increased permeability of endothelial cell monolayers and stimulated melanoma transendothelial cell migration. In vivo, melanoma cells expressing EphA2-S897E or active Cdc42 showed superior lung retention following tail-vain injection. Analysis of BRAF inhibitor-sensitive and -resistant melanoma cells demonstrated resistance to be associated with an MAT switch, upregulation of Cdc42 activity, increased invasion, and transendothelial migration. The drug resistant metastatic state was dependent upon histone deacetylase 8 (HDAC8) activity. Silencing of HDAC8 lead to inhibition of EphA2 and AKT phosphorylation, reduced invasion and impaired melanoma cell-endothelial cell interactions. In summary, we have demonstrated that the metastatic state associated with acquired BRAF inhibitor resistance is dependent on non-canonical EphA2 signaling, leading to increased melanoma-endothelial cell interactions and enhanced tumor dissemination.
2020-11-18 | PXD020241 | Pride