The CoREST Repressor Complex Mediates Phenotype Switching and Therapy Resistance in Melanoma
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE156250 | GEO | 2024/02/01
REPOSITORIES: GEO
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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.
2024-02-22 | GSE254701 | 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. 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 selective BRAF inhibitors (BRAFi) has produced remarkable outcomes for patients with advanced cutaneous melanoma harboring a BRAFV600E mutation. Unfortunately, the majority of patients eventually develop drug-resistant disease through a variety of mechanisms. We previously described the creation of a panel of spontaneously BRAFi/MEKi-resistant A375 melanoma cells that displayed multiple different resistance mechanisms arising within the same parental cell population. These resistance mechanisms include (i) rearrangements in the BRAF gene resulting in truncation of the N-terminal regulatory domain or tandem duplication of the BRAF kinase domain, (ii) loss of Ras-GAP NF1, and (iii) a slower arising form of drug resistance associated with a more spread cell morphology and increased phospho-MEK S298, a characteristic of cells with increased Rac1 signaling. We provide here comprehensive gene expression profiling for this panel of cell lines. Rac1 mutation, particularly the P29S variant, is common in melanoma patients, where it is associated with BRAFi/MEKi resistance and worse clinical outcomes. Here we delineate mechanisms of Rac1-driven MAPKi-resistance and identify strategies to inhibit the growth of this class of cutaneous melanomas. We find that Rac1-driven melanomas manifest pleiotropic resistance mechanisms including (i) reduced dependence on BRAF/MEK, (ii) activation of alternative MAPK pathways utilizing Jun kinase and p38 MAP kinase, and (iii) a partial reliance on YAP/TAZ signaling. Importantly, although Rac1-driven melanoma cells display reduced dependence on BRAF/MEK, they are not completely ERK-independent. Moreover, the presence of activated Rac1 appears to create a dependency on focal adhesion kinase (FAK) signaling in undifferentiated melanoma cells. As a result, we find that, despite the pleiotropic mechanisms of Rac1-driven MAPKi resistance, combined inhibition of MEK and FAK with avutometinib plus defactinib is a promising approach for suppressing the growth of Rac1-driven cells. Thus, the avutometinib plus defactinib combination, which is currently being investigated for brain metastatic cutaneous melanoma may also have utility against Rac1-driven MAPKi-resistance in heavily pre-treated, advanced disease.
2024-12-26 | GSE285131 | 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 | 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: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: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:The emergence of effective inhibitors for BRAF-mutant melanoma has had major impact on clinical management of melanoma 1,2. The initial success of such treatments, however, has been limited due to the propensity of melanomas to develop resistance 3-5. In most cases, mechanisms underlying BRAFi-resistance include activation of genetic or epigenetic pathways that circumvent targeted BRAF and restore MAPK and related signaling to levels sufficient to encourage tumorigenesis 3-7. This outcome has led to development of combination therapies targeting both BRAF and associated pathways, such as MEK and PI3K 8,9, albeit, with limited success. Furthermore, 50% of melanomas, such as those harboring NRAS and NF1 mutations, lack BRAF mutations and are thus not amenable to BRAFi therapy 10,11. Thus tumor chemoresistance and the lack of therapies for BRAF wild-type (WT) tumors remains a major clinical challenge. Disrupting the eukaryotic translation initiation factor 4F (eIF4F) complex has been an appealing strategy to potentiate effectiveness of existing cancer therapies. We identify that the small molecule SBI-0640756 (SBI-756) binds to eIF4G1 and dissociates it from eIF4E, leading to disruption of the eIF4F complex. SBI-756 treatment also inhibited AKT, NF-κB and mTOR signaling. We detected the melanoma cell lines have different response to SBI-756. It important to invertigate genes and pathways in melanoma cells resistant to SBI-756.
2016-05-01 | GSE66401 | GEO