Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA376198 | ENA |
REPOSITORIES: ENA
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Project description:Nearly 30% of all malignant melanomas harbor somatic mutations in NRAS. However, there are currently no effective targeted therapies for this tumor type. The bromodomain and extra terminal domain (BET) family of proteins are transcriptional regulators that serve as scaffolds to facilitate gene transcription by binding to acetylated lysine residues in the N-terminal tail of histones. BET/BRD proteins have emerged as therapeutic targets in a broad range of tumors. We found that BET proteins are overexpressed in NRAS mutant melanoma, and that high levels of BET family member BRD4 are associated with poor patient survival, suggesting that BRD4 plays a key role in melanoma. Consequently, we hypothesized that these epigenetic regulators constitute potential vulnerabilities that can be exploited for melanoma treatment. We found that genetic or pharmacological inhibition of BET/BRD proteins decreases viability and inhibits proliferation of NRAS mutant melanoma cells, as well as BRAF/MEK-inhibitor resistant melanoma cells harboring concurrent BRAF/NRAS mutations. However, BET inhibitors when used as single agents were either cytostatic (in vitro) or ineffective (in vivo). We therefore evaluated combinations that could maximize the efficacy of BET inhibitors in NRAS mutant melanoma. Here we report that co-targeting BET and MEK synergistically restrained tumor growth and significantly prolonged the survival of NRAS-mutant tumor bearing mice. RNA-sequencing and RPPA analysis revealed that co-treatment with BETi/MEKi synergistically downregulated cell cycle regulators and activated caspase-7. This study demonstrates that combined BET and MEK inhibition elicits robust synergistic therapeutic effects and supports the clinical utility of this combination therapy for NRAS mutant melanoma patients.
2018-02-20 | GSE95153 | GEO
Project description:NRAS-mutant melanoma is currently a challenge to treat. This is due to an absence of inhibitors directed against NRAS, along with acquired and adaptive resistance of this tumor type to inhibitors in the MAPK pathway. Inhibitors to MEK (mitogen-activated protein kinase kinase) have shown some promise for this tumor type. In this work we explored the use of MEK inhibitors for NRAS-mutant melanoma, and at the same time investigated the impact of the brain micro-environment, specifically astrocytes, on the response of a melanoma brain metastatic cell line to MEK inhibition. This led to the surprising finding that astrocytes enhance the sensitivity of melanoma tumors to MEK inhibitors (MEKi). We show that MEKi cause an upregulation of the transcription factor ID3, but this is blocked by conditioned media from astrocytes. We show that silencing ID3 enhances the sensitivity of melanoma to MEK inhibitors, thus mimicking the effect of the brain microenvironment. Moreover, we report that ID3 is a client protein of the chaperone HSP70, and that HSP70 inhibition causes ID3 to misfold and accumulate in a detergent-insoluble fraction in cells. We show that HSP70 inhibitors synergize with MEK inhibitors against NRAS-mutant melanoma, and that this combination significantly enhances the survival of mice in two different models of NRAS-mutant melanoma. These studies highlight ID3 as a mediator of adaptive resistance, and support the combined use of MEK and HSP70 inhibitors for the therapy of NRAS-mutant melanoma.
2022-06-30 | GSE179235 | GEO
Project description:The Ras/MEK/ERK pathway has been the primary focus of targeted therapies in melanoma, given that it is aberrantly activated in almost 80% of human cutaneous melanomas (~50% BRAFV600 mutations and ~30% NRAS mutations). While targeted therapies have yielded success in BRAFV600 mutant melanoma patients, such therapies have been ineffective in NRAS mutant melanomas in part due to their cytostatic effects and primary resistance in this patient population. Here, we demonstrate that increased Rho/MRTF-pathway activation correlates with high intrinsic resistance to trametinib, a MEK inhibitor, in a panel of NRAS mutant melanoma cell lines. Combination of trametinib with the Rho/MRTF-pathway inhibitor, CCG-222740, synergistically reduced cell viability in NRAS mutant melanoma cell lines in vitro. Furthermore, the combination of CCG-222740 with trametinib induced apoptosis and reduced clonogenicity in the highly trametinib-resistant SK-Mel-147 cells. These findings suggest a role of the Rho/MRTF-pathway in high intrinsic trametinib resistance to a subset of NRAS mutant melanoma cell lines and highlights the potential of concurrently targeting the Rho/MRTF-pathway and MEK in NRAS mutant melanomas.
2019-07-16 | GSE134320 | GEO
Project description:The Ras/MEK/ERK pathway has been the primary focus of targeted therapies in melanoma, given that it is aberrantly activated in almost 80% of human cutaneous melanomas (~50% BRAFV600 mutations and ~30% NRAS mutations). While targeted therapies have yielded success in BRAFV600 mutant melanoma patients, such therapies have been ineffective in NRAS mutant melanomas in part due to their cytostatic effects and primary resistance in this patient population. Here, we demonstrate that increased Rho/MRTF-pathway activation correlates with high intrinsic resistance to trametinib, a MEK inhibitor, in a panel of NRAS mutant melanoma cell lines. Combination of trametinib with the Rho/MRTF-pathway inhibitor, CCG-222740, synergistically reduced cell viability in NRAS mutant melanoma cell lines in vitro. Furthermore, the combination of CCG-222740 with trametinib induced apoptosis and reduced clonogenicity in the highly trametinib-resistant SK-Mel-147 cells. These findings suggest a role of the Rho/MRTF-pathway in high intrinsic trametinib resistance to a subset of NRAS mutant melanoma cell lines and highlights the potential of concurrently targeting the Rho/MRTF-pathway and MEK in NRAS mutant melanomas.
2018-12-30 | GSE115938 | GEO
Project description:Targeted therapies have the potential to revolutionize cancer care by providing personalized treatment strategies that are less toxic and more effective but it is clear that for most solid tumors suppression of a single target is not sufficient to prevent development of resistance. A powerful method to identify mechanisms of resistance and targets for combination therapy is to use an in vivo genetic approach. We have developed a novel retroviral gene delivery mouse model of melanoma that permits control of gene expression post-delivery using the tetracycline (tet)-regulated system. In this study we used this melanoma model to select for resistant tumors following genetic inhibition of mutant NRAS. Analysis of tumors that became resistant to NRAS suppression revealed that the most common mechanism of resistance was overexpression of the Met receptor tyrosine kinase (RTK). Importantly, inhibition of Met overcomes NRAS resistance in this context. Analysis of NRAS mutant human melanoma cells revealed that inhibition of MEK is also associated with adaptive RTK signaling. Furthermore, co-inhibition of RTK signaling and MEK overcomes acquired MEK inhibitor resistance in NRAS mutant melanoma. These data suggest that combined inhibition of RTK and MEK signaling is a rational therapeutic strategy in mutant NRAS driven melanoma.
2014-10-31 | GSE51906 | GEO
Project description:Targeted therapies have the potential to revolutionize cancer care by providing personalized treatment strategies that are less toxic and more effective but it is clear that for most solid tumors suppression of a single target is not sufficient to prevent development of resistance. A powerful method to identify mechanisms of resistance and targets for combination therapy is to use an in vivo genetic approach. We have developed a novel retroviral gene delivery mouse model of melanoma that permits control of gene expression post-delivery using the tetracycline (tet)-regulated system. In this study we used this melanoma model to select for resistant tumors following genetic inhibition of mutant NRAS. Analysis of tumors that became resistant to NRAS suppression revealed that the most common mechanism of resistance was overexpression of the Met receptor tyrosine kinase (RTK). Importantly, inhibition of Met overcomes NRAS resistance in this context. Analysis of NRAS mutant human melanoma cells revealed that inhibition of MEK is also associated with adaptive RTK signaling. Furthermore, co-inhibition of RTK signaling and MEK overcomes acquired MEK inhibitor resistance in NRAS mutant melanoma. These data suggest that combined inhibition of RTK and MEK signaling is a rational therapeutic strategy in mutant NRAS driven melanoma. Reversible NRAS Q61R expression in the melanocytes of DCT-TVA;Ink4a/Arf lox/lox mice (FVB/n) was achieved by transducing the animals with Tet-off and TRE-NRASQ61R-IRES-Cre avian leukosis viruses. After tumor initiation, the expression of NRAS Q61R was turned off by administrating doxycycline. Despite initial regression, tumors in 40% of mice developed resistance to NRAS Q61R withdraw. Seven resistant tumors and one control tumor where NRAS Q61R expression was not interrupted were subjected to genome-wide gene expression profiling.
2014-10-31 | E-GEOD-51906 | biostudies-arrayexpress
Project description:About 25% of melanoma harbor activating NRAS mutations, which are associated with aggressive disease therefore requiring a rapid anti-tumor intervention. However, no efficient targeted therapy options are currently available for patients with NRAS-mutant melanoma. MEK inhibitors (MEKi) appear to display a moderate anti-tumor activity and also immunological effects in NRAS-mutant melanoma, providing an ideal backbone for combination treatments. In this study, the MEKi binimetinib, cobimetinib, and trametinib combined with the BRAF inhibitors (BRAFi) encorafenib, vemurafenib, and dabrafenib were investigated for their ability to inhibit proliferation, induce apoptosis and alter the expression of immune modulatory molecules in sensitive NRAS-mutant melanoma cells using 2D and 3D cell culture models and transcriptome analyses. Furthermore, NRAS-mutant melanoma cells resistant to the three BRAFi/MEKi combinations were established to characterize the mechanisms contributing to their resistance. All BRAFi induced a stress response in the sensitive NRAS-mutant melanoma cells thereby significantly enhancing the anti-proliferative and pro-apoptotic activity of the MEKi analyzed. Furthermore, BRAFi/MEKi combinations upregulated immune relevant molecules, such as ICOS-L, components of antigen-presenting machinery and the “don’t eat me signal” molecule CD47 in the melanoma cells. The BRAFi/MEKi-resistant, NRAS-mutant melanoma cells counteracted the molecular and immunological effects of BRAFi/MEKi by upregulating downstream mitogen-activated protein kinase pathway molecules, inhibiting apoptosis and promoting immune escape mechanisms. Together, this study reveals potent molecular and immunological effects of BRAFi/MEKi in sensitive NRAS-mutant melanoma cells that may be exploited in new combinational treatment strategies for patients with NRAS-mutant melanoma.
2023-11-14 | GSE245262 | GEO
Project description:In the present work we propose a new therapy for NRAS mutant melanoma. Simultaneous inhibition of MEK and ROCK caused induction of BimEL , PARP, and Puma, and hence apoptosis. In vivo, MEK and ROCK inhibition suppressed growth of established tumors. Our findings warrant clinical investigation of the effectiveness of combinatorial targeting of MAPK/ERK and ROCK in NRAS mutant melanoma.
2015-03-11 | PXD000528 | Pride
Project description:The transcriptome of 3 cutaneous melanoma cell lines treated with Control (DMSO), CDK9 inhibitor (CDKI73), BET/bromodomain and extra terminal inhibitors IBET151, or combination of both drugs was assessed using RNAseq. Dysregulation of epigenetic modifiers is a frequent event in melanoma and underlies many aspects of melanoma biology including resistance to targeted and immunotherapies. Here we report that dual targeting of BET and CDK9 proteins have synergistic effects against melanoma cells in vitro and in vivo. The BET inhibitor (IBET151) and CDK9 inhibitor (CDKI73) synergistically killed melanoma cells in vitro independent of their BRAF or NRAS mutation status. The combination of drugs markedly inhibited the growth of human melanoma C002M cells in vitro in 3D spheroids and in vivo in NSG mice compared to vehicle control and the individual drugs (p<0.05). Cell death was associated with mitochondrial depolarisation and caspase dependent apoptosis with cleavage of PARP1 as well as downregulation of anti-apoptotic proteins BCL2, BCLXL and MCL1. GSEA revealed downregulation of hallmark gene-sets associated with E2F, G2M checkpoint and c-MYC. Survival analysis showed worse prognosis with high G2M, E2F or c-MYC gene signatures suggesting biomarkers of response of BET and CDK9 inhibitors in melanoma. This novel combination of epigenetic inhibitors targets multiple downstream genes leading to cell death of melanoma cells in vitro and in vivo and warrant further investigation for treatment of melanoma in patients not responding to current therapies.
2021-02-23 | GSE167241 | GEO
Project description:Combining multiple therapeutic strategies in NRAS/BRAF mutant melanoma – namely MEK/BRAF kinase inhibitors, immune checkpoint inhibitors, and targeted immunotherapies – may offer an improved survival benefit by overcoming limitations associated with any individual therapy. Still, optimal combination, order, and timing of administration remains under investigation. Here, we measure how MEK inhibition alters anti-tumor immunity by utilizing quantitative immunopeptidomics to profile changes the peptide MHC (pMHC) repertoire. These data reveal a collection of tumor antigens whose presentation levels are selectively augmented following therapy, including several epitopes present at over 1000 copies-per-cell. We leveraged the tunable abundance of MEKi-modulated antigens by targeting 4 epitopes with pMHC-specific T cell engagers and antibody drug conjugates, enhancing cell killing in tumor cells following MEK inhibition. These results highlight drug treatment as a means to enhance immunotherapy efficacy by targeting specific upregulated pMHCs and provide a methodological framework for identifying, quantifying, and therapeutically targeting additional epitopes of interest.
2023-03-11 | PXD029860 | Pride