Project description:We performed RNA-seq in parental MEL-XY3 melanoma cells (JM9) and in MEL-XY3 SUR cells obtained in vitro after 5 week treatment with PLX4032 (JM7)
Project description:Targeted therapy with small molecules inhibiting BRAF and MEK kinase represents a therapeutic option in advanced metastatic melanoma although drug resistance limits the achievement of persistent cures. The genomic analyses of tumors from patients developing treatment resistance indicate that drug tolerance may result from non-mutational events occurring in the tumor microenvironment. To identify tumor specific transcriptional changes related to resistance to the BRAF-inhibitor PLX4032, cell lines with acquired resistance to PLX4032 were generated from six sensitive melanoma lines by chronic in vitro drug exposure (Vergani E, Oncotarget 2016) and analyzed for gene expression profiles; in addition a set of cell lines with intrinsic resistance was included for comparison. Cell lines were obtained from metastatic surgical specimens and were previously genetically characterized (Daniotti M, Oncogene 2004; Vergani E, JID 2022, accepted).
Project description:Gene and microRNA expression profiles were generated for a melanoma cell line resistant to the BRAF inhibitor PLX4032 and its parental cell line in order to identify altered gene-microRNA regulatory networks. Results showed that CCL2 acts as an autocrine factor and coordinately regulates, via HIF1, miR-34a, miR-100 and miR-125b, which are involved in cell proliferation and apoptosis. Inhibition of CCL2 and of the specific miRNAs restores sensitivity to BRAF inhibitors.
Project description:Gene and microRNA expression profiles were generated for a melanoma cell line resistant to the BRAF inhibitor PLX4032 and its parental cell line in order to identify altered gene-microRNA regulatory networks. Results showed that CCL2 acts as an autocrine factor and coordinately regulates, via HIF1, miR-34a, miR-100 and miR-125b, which are involved in cell proliferation and apoptosis. Inhibition of CCL2 and of the specific miRNAs restores sensitivity to BRAF inhibitors.
Project description:Genome wide DNA methylation profiling of control and PLX4032 resistant clones to identify resistance-associated methylome alternations, and to integrate with transcriptome analysis. Results provide insight into clonal epigentic adaption of PLX4032 resistance in BRAF V600E melanoma.
Project description:NGS-derived transcriptome profiling (RNA-seq) of control and PLX4032 resistant clones to identify resistance-associated gene-expression changes and pathway enrichments, and to integrate with exome and methylome analysis. Results provide insight into PLX4032 resistance in BRAF V600E melanoma.
Project description:The activation of transcriptional coactivators YAP and its paralog TAZ has been shown to promote resistance to anti-cancer therapies. YAP/TAZ activity is tightly coupled to actin cytoskeleton architecture. However, the influence of actin remodeling on cancer drug resistance remains largely unexplored. Here, we report a pivotal role of actin remodeling in YAP/TAZ-dependent BRAF inhibitor resistance in BRAF V600E mutant melanoma cells. Melanoma cells resistant to BRAF inhibitor PLX4032 exhibit an increase in actin stress fiber formation, which appears to promote the nuclear accumulation of YAP/TAZ. Knockdown of YAP/TAZ overcomes PLX4032 resistance, whereas overexpression of constitutively active YAP induces resistance. Moreover, inhibition of actin polymerization and cytoskeletal tension in melanoma cells suppresses both YAP/TAZ activation and PLX4032 resistance. Our siRNA library screening identifies actin dynamics regulator TESK1 as a novel vulnerable point of the YAP/TAZ-dependent resistance pathway. These results suggest that inhibition of actin remodeling is a promising synthetic lethal strategy to suppress resistance in BRAF inhibitor therapies.
Project description:Melanoma is an aggressive skin cancer with increasing incidence worldwide. The development of BRAF kinase inhibitors as targeted treatments for patients with BRAF-mutant tumours contributed profoundly to an improved overall survival of patients with metastatic melanoma. Despite these promising results, the emergence of rapid resistance to targeted therapy remains a serious clinical issue. To investigate the impact of BRAF inhibitors on miRNomes and transcriptomes, we used in vitro melanoma models consisting of BRAF inhibitor-sensitive and -resistant cell lines generated in our laboratory. miRNA and gene expression were assessed by microarray analyses of the BRAF inhibitor sensitive melanoma cells A375, IGR37, and 501Mel, as well as on the vemurafenib (PLX4032) - resistant cells A375_XP, IGR37_XP, 501Mel_XP, and dabrafenib (GSK2118436) - resistant cells A375_GP, IGR37_GP, 501Mel_GP. For each cell line the microarray experiment was performed in duplicates.
Project description:Melanoma is an aggressive skin cancer with increasing incidence worldwide. The development of BRAF kinase inhibitors as targeted treatments for patients with BRAF-mutant tumours contributed profoundly to an improved overall survival of patients with metastatic melanoma. Despite these promising results, the emergence of rapid resistance to targeted therapy remains a serious clinical issue. To investigate the impact of BRAF inhibitors on miRNomes and transcriptomes, we used in vitro melanoma models consisting of BRAF inhibitor-sensitive and -resistant cell lines generated in our laboratory. miRNA and gene expression were assessed by microarray analyses of the BRAF inhibitor sensitive melanoma cells A375, IGR37, and 501Mel, as well as on the vemurafenib (PLX4032) - resistant cells A375_XP, IGR37_XP, 501Mel_XP, and dabrafenib (GSK2118436) - resistant cells A375_GP, IGR37_GP, 501Mel_GP. For each cell line the microarray experiment was performed in duplicates.