SiNRAS and siDGKH knockdown in NRAS mutant melanoma cells
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE312301 | GEO | 2026/05/26
REPOSITORIES: GEO
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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:NRAS activating mutations occur in 15-25% of melanoma patients. However, this subtype is more aggressive and refractory to current treatment modalities, including targeted MEK inhibitors, immunotherapies, and the recently emerging RAS inhibitors. Accordingly, identifying novel therapeutic targets and designing novel antimelanoma strategies is of utmost clinical relevance. Melanomas often harbor hyperactive nitric oxide synthases (NOS) which correlates strongly with poor prognosis. NOS is also known to be activated by ERK signaling. The nitric oxide so produced, induces nitrosylation, a post-translational modification, which dysregulates various kinases and phosphatases. We sensitized NRAS-mutant melanomas to targeted MEK inhibitors by inhibiting nitrosylation. This outcome revealed a strong correlation between global de-nitrosylation and downregulation of MEK-ERK cascade with a concomitant de-nitrosylation of NRAS and other small GTPases like Rho and Rac, dual specificity phosphatases, and ribosomal S6 kinase. In vivo, we observed extreme regression of NRAS-mutant melanoma tumors generated in an immunocompetent mouse model in response to a sequential nitrosylation inhibition and MEK inhibition. In addition to MEK-ERK downregulation, this strategy activated the CD8+ T cells in the tumor microenvironment. We conclude that while nitrosylation hyperactivates the RAS-RAF-MEK-ERK cascade, it also suppresses anti-melanoma immune response, bolstering progression and MEKi resistance. The underlying mechanism(s) will be crucial in identifying novel therapeutic vulnerabilities against aggressive, currently incurable NRAS-mutant melanomas with potential clinical application in other melanoma subtypes.
2025-05-02 | PXD050244 | Pride
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: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: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:Despite the advent of immune-oncological therapies, patients with advanced NRAS-mutant melanoma still have a significantly worse prognosis than their BRAF-mutant counterparts. This is mainly due to a high propensity for resistance to available therapies targeting the RAS/RAF/MEK/ERK mitogen-activated protein kinase (MAPK) pathway (MAPKi). Preclinical studies and mouse models have implicated the stress-activated MEK5/ERK5 MAPK cascade as a major resistance pathway activated by MAPKi-based targeted therapy in NRAS-mutant melanoma. Accordingly, MAPKi/ERK5i co-inhibition was capable of triggering a sustained cell cycle arrest in NRAS-mutant melanoma cells, but the key mediator(s) of its vigorous anti-proliferative effect remain elusive. Here, we further investigated the mechanism of MAPKi/ERK5i-induced cell cycle arrest in NRAS-mutant melanoma cells using both genetic methods and pharmacological inhibitors. Transcriptome analysis of human NRAS-mutant melanoma cells established that MAPKi/ERK5i-induced a near-complete shutdown of the mitotic machinery as consequence of a sustained G1 cell cycle arrest. This arrest was not only observed in diverse treatment-naïve melanoma cells but could also be induced in cells that already had developed resistance to therapeutic MEK inhibition (MEKi) and was accompanied by suppression of Cyclin D1 and E2F-mediated gene expression. Forced expression of Cyclin D1 and its effector kinase CDK4 restored cell cycle progression and mitotic gene expression in NRAS-mutant melanoma cells exposed to MEKi/ERK5i, implying Cyclin D/CDK4 activity as major target of combined MEKi/ERK5i. These findings suggest Cyclin D/CDK4 dependency as a major vulnerability of NRAS-mutant melanoma that could effectively be targeted by combined MAPKi/ERK5i.
2025-09-01 | GSE300191 | GEO
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:The eIF4F translation initiation complex plays a critical role in melanoma resistance to clinical BRAF and MEK inhibitors. In this study, we uncover a novel function of eIF4F in the negative regulation of the RAS/RAF/MEK/ERK mitogen-activated protein kinase (MAPK) signaling pathway. We demonstrate that eIF4F is essential for maintaining optimal ERK signaling intensity in treatment-naïve melanoma cells harboring BRAF or NRAS mutations. Specifically, the dual-specificity phosphatase DUSP6/MKP3, which acts as a negative feedback regulator of ERK activity, requires continuous production in an eIF4F-dependent manner to limit excessive ERK signaling driven by oncogenic RAF/RAS mutations. Treatment with small molecule eIF4F inhibitors disrupts the negative feedback control of MAPK signaling, leading to ERK hyperactivation and EGR1 overexpression in melanoma cells in vitro and in vivo. Furthermore, our quantitative analyses reveal a high spare signaling capacity in the ERK pathway, suggesting that eIF4F-dependent feedback keeps the majority of ERK molecules inactive under normal conditions. Overall, our findings highlight the crucial role of eIF4F in regulating ERK signaling flux and suggest that pharmacological eIF4F inhibitors can disrupt the negative feedback control of MAPK activity in melanomas with BRAF and NRAS activating mutations.
2024-10-04 | GSE273721 | GEO
Project description:Mutations in the NRAS oncogene are present in up to 20% of melanoma. Here, we show that interferon alpha-inducible protein 6 (IFI6) is necessary for NRASQ61K-induced transformation and melanoma growth. IFI6 was transcriptionally upregulated by NRASQ61K, and knockdown of IFI6 resulted in DNA replication stress due to dysregulated DNA replication via E2F2. This stress consequentially inhibited cellular transformation and melanoma growth via senescence or apoptosis induction depending on the RB and p53 pathway status of the cells. NRAS-mutant melanoma were significantly more resistant to the cytotoxic effects of DNA replication stress-inducing drugs, and knockdown of IFI6 increased sensitivity to these drugs. Pharmacological inhibition of IFI6 expression by the MEK inhibitor trametinib, when combined with DNA replication stress-inducing drugs, blocked NRAS-mutant melanoma growth. Collectively, we demonstrate that IFI6, via E2F2 regulates DNA replication and melanoma development and growth, and this pathway can be pharmacologically targeted to inhibit NRAS-mutant melanoma.
2016-09-08 | GSE69933 | GEO