Molecular changes induced in melanoma cells by stromal cells and anti-BRAF therapy.
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE67637 | GEO | 2015/08/01
SECONDARY ACCESSION(S): PRJNA280524
REPOSITORIES: GEO
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Project description:Tumor-associated stromal cells can enable cancer cells to become insensitive to therapy. They can promote aggressive phenotype in cancer cells, which become less responsive to drugs such as BRAF inhibitors (BRAFi) used to treat melanomas. To clarify potential mechanism behind stromal influence on melanoma, we analyzed gene expression in Melmet 5 melanoma cells grown as mono-cultures or co-cultures with lung fibroblasts with/without BRAFi. We have shown that Melmet 5 growing as co-cultures gained a de-differentiated, invasive transcriptional state, which is known to be linked to BRAFi-resistance. The transcriptional changes induced by BRAFi were much larger in Melmet 5 mono-cultures compared to co-cultures, indicating a much dampened transcriptional response to BRAFi in melanoma under the influence of fibroblasts. We conclude that interaction with the stromal cells stimulate melanoma cell transition to the invasive de-differentiated phenotype, leading to a worse response to BRAF inhibitors. Total RNA was isolated from Melmet 5 cell line growing as mono- or co-cultures with fibroblasts for 72 hours and treated with BRAFi for the last 24 hours.
2015-08-01 | E-GEOD-67637 | biostudies-arrayexpress
Project description:About half of all melanomas harbor a constitutively active mutant BRAFV600E/K kinase that can be selectively inhibited by targeted BRAF inhibitors (BRAFi). While patients treated with BRAFi initially exhibit measurable clinical improvement, the majority of patients eventually develop drug resistance and relapse. We observe significant elevation of WNT5A in a subset of tumors from patients exhibiting disease progression on BRAFi therapy. WNT5A transcript and protein are also elevated in BRAFi-resistant melanoma cell lines generated by long-term in vitro treatment with BRAFi. RNAi-mediated reduction in levels of endogenous WNT5A in melanoma decreases cell growth, increases apoptosis in response to BRAFi challenge, and decreases the activity of pro-survival AKT signaling. Overexpression of WNT5A conversely promotes melanoma growth and tumorigenesis and activates AKT signaling. Similar to WNT5A knockdown, knockdown of the WNT receptors FZD7 and RYK inhibits growth, sensitizes melanoma cells to BRAFi, and reduces AKT activation. Together, these findings suggest that chronic BRAF inhibition elevates WNT5A expression, which then acts through FZD7 and RYK to promote AKT signaling, leading to increased growth and therapeutic resistance. Increased WNT5A expression in BRAFi-resistant melanomas also correlates with an associated transcriptional signature, which identifies potential therapeutic targets to reduce clinical resistance to BRAFi. Expression of WNT5A-correlated genes was compared in melanoma cell lines generated to be resistant to PLX4032 and the their associated naïve parental line Basal expression of the WNT5A-correlated genes was also measured in experiments comparing each naïve line to a mixed reference pool containing equal amounts of 47 melanoma cell lines.
2014-03-06 | E-GEOD-55583 | biostudies-arrayexpress
Project description:The use of BRAF inhibitors, specific of the BRAFV600E mutation, as a therapeutic strategy for melanoma has significantly improved patient survival. However, resistance mechanisms appear systematically and limit the benefit of treatment. Here we show that AhR transcription factor participates in BRAFi resistance and is associated with the acquisition of an invasive and a dedifferentiated melanoma phenotype by controlling the expression of specific genes. AhR also induces the activation of the c-Src pathway through its phosphorylation, associated with BRAFi resistance. The use of a specific inhibitor of c-Src such as Dasatinib makes it possible to sensitize resistant cells to BRAFi and to prevent the acquisition of an invasive melanoma phenotype by regulating the expression of the AhR-dependent genes.
2022-10-18 | GSE166617 | GEO
Project description:BRAF-inhibitor (BRAFi)-resistance compromises long term survivorship of malignant melanoma patients, and mutant NRAS is a major mediator of BRAFi-resistance. We have employed NanoString nCounterTM transcriptomic analysis of isogenic human malignant melanoma cells that differ only by NRAS mutational status (BRAFi-sensitive A375-BRAFV600E/NRASQ61 versus BRAFi-resistant A375-BRAFV600E/NRASQ61K), identifying modulation of specific gene expression networks as a function of NRASQ61K-status.
2021-09-23 | GSE184633 | GEO
Project description:About half of all melanomas harbor a constitutively active mutant BRAFV600E/K kinase that can be selectively inhibited by targeted BRAF inhibitors (BRAFi). While patients treated with BRAFi initially exhibit measurable clinical improvement, the majority of patients eventually develop drug resistance and relapse. We observe significant elevation of WNT5A in a subset of tumors from patients exhibiting disease progression on BRAFi therapy. WNT5A transcript and protein are also elevated in BRAFi-resistant melanoma cell lines generated by long-term in vitro treatment with BRAFi. RNAi-mediated reduction in levels of endogenous WNT5A in melanoma decreases cell growth, increases apoptosis in response to BRAFi challenge, and decreases the activity of pro-survival AKT signaling. Overexpression of WNT5A conversely promotes melanoma growth and tumorigenesis and activates AKT signaling. Similar to WNT5A knockdown, knockdown of the WNT receptors FZD7 and RYK inhibits growth, sensitizes melanoma cells to BRAFi, and reduces AKT activation. Together, these findings suggest that chronic BRAF inhibition elevates WNT5A expression, which then acts through FZD7 and RYK to promote AKT signaling, leading to increased growth and therapeutic resistance. Increased WNT5A expression in BRAFi-resistant melanomas also correlates with an associated transcriptional signature, which identifies potential therapeutic targets to reduce clinical resistance to BRAFi.
2014-03-06 | GSE55583 | GEO
Project description:BRAF oncogene is mutated in ~50% of human cutaneous melanomas. The BRAF V600E mutation leads to constitutive activation of the mitogen-activated protein kinase (MAPK) pathway fuelling cancer growth. The inhibitors of BRAF V600E (BRAFi), lead to massive and high response rate. However, BRAFi-resistant cells that operate as a cellular reservoir for relapses severely limits the duration of the clinical response. The recent depiction of these resistant cells did not identify druggable targets to ensure long-term survival under BRAFi. Here, we identify the aryl hydrocarbon receptor (AhR) as a target to eradicate resistant cells. We show that BRAFi bind to AhR on a new site, named beta-pocket, and reprogram gene expression independently of its partner ARNT. beta-pocket activation induces a pigmentation signature, which is associated to BRAFi-induced cell death of sensitive BRAF V600E melanoma cells and tumour shrinkage. Intriguingly, in resistant cells, BRAFi does not induced a pigmentation signature since these cells display another AhR program; AhR-ARNT dependant. By this way, AhR directs several key BRAFi-resistant genes. At single cell level, this constitutive activation of AhR-ARNT is identified in rare cells before BRAFi-treatment of melanoma tumours and an enrichment of these alpha-cells is observed under BRAFi. Our data strongly suggest that an endogenous AhR ligand activates AhR-ARNT via the canonical AhR pocket (alpha-pocket), thus favouring BRAFi-resistant gene expression. Importantly, we identify the clinically compatible AhR antagonist, the resveratrol (RSV), able to abrogate the deleterious constitutive activation of AhR and to reduce the cellular reservoir for the relapse. Taken together, this work reveals that constitutive AhR signalling drives BRAFi resistance and constitutes a therapeutic target to achieve long-term patient survival under BRAFi. More broadly, the constitutive activation of AhR by endogenous ligands is in line with the ability of UV radiations to generate potent AhR ligands and to favour melanoma onset.
2018-11-29 | GSE104869 | 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 | GSE199405 | 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 | GSE232693 | 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
Project description:Virtually all patients with BRAF-mutant melanoma develop resistance to MAPK inhibitors largely through non-mutational events. Although the epigenetic landscape is shown to be altered in therapy-resistant melanomas and other cancers, a specific targetable epigenetic mechanism has not been validated to date. Here, we evaluate the CoREST repressor complex and the recently developed bivalent inhibitor, corin, within the context of melanoma phenotype plasticity and therapeutic resistance. We find that CoREST is a critical mediator of the major distinct melanoma phenotypes and that corin treatment of melanoma cells leads to phenotype reprogramming. Global assessment of transcript and chromatin changes conferred by corin reveals specific effects on histone marks connected to EMT-associated transcription factors and the dual-specificity phosphatases (DUSPs). Remarkably, treatment of BRAF inhibitor (BRAFi)-resistant melanomas with corin promotes resensitization to BRAFi therapy. DUSP1 is consistently downregulated in BRAFi-resistant melanomas which is reversed by corin treatment and associated with inhibition of p38 MAPK activity and resensitization to BRAFi therapies. Moreover, this activity can be recapitulated by the p38 MAPK inhibitor, BIRB 796. These findings identify the CoREST repressor complex as a central mediator of melanoma phenotype plasticity and resistance to targeted therapy and suggest that CoREST inhibitors may prove beneficial to patients with BRAFi- resistant melanoma.
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