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ABSTRACT:
PROVIDER: PRJNA887367 | ENA |
REPOSITORIES: ENA
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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:Resistance of NRAS mutant melanoma to MEKi
| PRJNA882362 | ENA
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:Purpose: Tumor radioresistance can be driven by ERK phosphorylation and its downstream targets. In this context, melanomas harboring constitutive MAPK/ERK activation have been considered for targeted radionuclide therapy (TRT) with a radiolabeled melanin tracer ([131I]ICF01012), alone or in combination with MEK inhibitors (MEKi). Experimental design: We used three dimensional (3D) melanoma spheroid models to evaluate the effects of TRT in combination with MEKi, in human BRAFV600E SK-MEL-3, NRASQ61K 1007 and WT B16F10 murine melanomas. TRT was assessed in vivo using the syngeneic model C57Bl5/NRAS 1007 for biodistribution, dosimetry, efficiency and molecular mechanisms. Results: In spheroids, TRT cooperated with MEKi to increase apoptosis in both BRAF- and NRAS-mutant models that were resistant to TRT-induced apoptosis. However NRASQ61K spheroids were highly radiosensitive towards [131I]ICF01012-TRT. Actually, mice bearing NRAS1007 melanoma and receiving 18.5MBq of [131I]ICF01012 had a significant extended survival (median: 92 vs 44 days, p < 0.0001), associated with a 93 Gy tumor deposit, leading to a dramatic decrease of tumor growth. Furthermore, the number of lymph node metastases was reduced in mice receiving [131I]ICF01012. Comparative transcriptomic analyses confirm a decrease of mitosis, proliferation and metastasis signature in TRT-treated tumors vs control tumors. These analyses also suggest that in this NRAS-melanoma, TRT acts through an increase of oxidation and inflammation as well as P53 activation. Conclusions: Our data support the view that combining [131I]ICF01012-TRT with MEKi can be of benefit for the treatment of advanced pigmented BRAF-mutant melanoma. Likewise, [131I]ICF01012 alone can be considered as a new potential NRAS-mutant melanoma treatment.
2021-03-31 | GSE162536 | 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. 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: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: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:The majority of BRAFV600 mutant melanomas regress in response to BRAF/MEK inhibitors (BRAFi/MEKi). Yet nearly all relapse within the first two years. Most BRAFi/MEKi-resistant tumors are cross-resistant to immunotherapies, highlighting the need to prevent and circumvent resistance. We recently showed that androgen receptor (AR) activity is required for sustained melanoma cells proliferation and tumorigenesis. Here we find that AR expression is markedly increased in BRAFi resistant melanoma cells as well as in sensitive cells already at very early times of BRAFi exposure. Proliferation and tumorigenicity of BRAFi resistant melanoma cells are blunted by genetic or pharmacologic suppression of AR activity, while AR overexpression is by itself sufficient to rendersmelanoma cells BRAFi/MEKi-resistant. Increased AR elicits transcriptional changes linked with AXL-positive BRAFi resistant subpopulations and induces expression of PAI-1 and EGFR, two determinants of melanoma progression that associate with elevated AR expression in clinical cohorts. Our results point to increased AR signaling as a determinant of melanoma BRAFi resistance, which can be counteracted by AR as well as PAI-1 and EGFR inhibitors.
2023-08-03 | GSE232690 | GEO