Discovery of resistance mechanisms to the BRAF inhibitor vemurafenib in metastatic BRAF mutant melanoma
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PROVIDER: EGAS00001000551 | EGA |
REPOSITORIES: EGA
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Project description:Multiple BRAF inhibitor resistance mechanisms have been described, however their relative frequency, clinical correlates, and effect on subsequent therapy have not been assessed in patients with metastatic melanoma. Excised progressing BRAFV600 mutant melanoma metastases (Prog) from patients treated with dabrafenib (n=22) or vemurafenib (n=8) were analyzed for known resistance mechanisms. Oncogenic signaling in Prog and matched pre-treatment tumors was examined using gene expression analysis. Resistance mechanisms were correlated with clinicopathologic features and outcome. A resistance mechanism was identified in 21/38 (55%) Prog samples from 30 patients; BRAF splice variants (n=12, 32%), N-RAS mutations (n=3, 8%), BRAF amplification (n=3, 8%), MEK1/2 mutations (n=3, 8%) and an AKT1 mutation (n=1, 3%). Four Progs tumours displayed multiple resistance mechanisms, and four patients with multiple Progs demonstrated inter-tumoral heterogeneity of resistance mechanisms. Six (21%) of 29 Progs showed loss of MAPK activity by gene expression analysis. These MAPK-inhibited Progs had unknown resistance mechanisms, and these patients had a shorter progression-free survival than patients with MAPK re-activated Progs. There were no responses to subsequent targeted therapy, even when the identified mechanism of resistance was predicted to be responsive. Heterogeneity of resistance mechanisms was common between patients, within patients and within individual tumors. The MAPK pathway remained inhibited in a subset of resistant tumors with unknown mechanisms of resistance, and the outcomes of patients with these tumors are poor. The use of sequential targeted therapies based on the molecular characteristics of a single progressing biopsy is unlikely to provide improved clinical outcomes. Total RNA was obtained from fresh-frozen melanoma tumour samples from patients before commencing treatment with dabrafenib or vemurafenib and at time of tumour progression.
2014-02-19 | E-GEOD-50509 | biostudies-arrayexpress
Project description:We propose to biopsy 20 consented BRAF mutant melanoma patients at Addenbrooke's Hospital pre-treatment with vemurafenib and also upon the development of resistant disease, with the aim of using exome sequence and SNP6 data to identify novel sequence variants and copy number alterations that can be used to validate observed resistance mechanisms in our cell line models and also to use these models to inform as to likely candidate small molecule inhibitors to overcome resistance and that could be tested in the clinical trial setting.
| EGAS00001000812 | EGA
Project description:We propose to biopsy 20 consented BRAF mutant melanoma patients at Addenbrooke's Hospital pre-treatment with vemurafenib and also upon the development of resistant disease, with the aim of using exome sequence and SNP6 data to identify novel sequence variants and copy number alterations that can be used to validate observed resistance mechanisms in our cell line models and also to use these models to inform as to likely candidate small molecule inhibitors to overcome resistance and that could be tested in the clinical trial setting.
| EGAS00001000813 | EGA
Project description:BRAF inhibitors are widely employed in the treatment of melanoma with the BRAF V600E mutation. However, the development of resistance greatly compromises their therapeutic efficacy. Here, we elucidate the role of polyamine biosynthesis and its regulatory mechanisms in promoting BRAF inhibitor resistance. Leveraging CRISPR-Cas9 screens, we identify AMD1 (S-adenosylmethionine decarboxylase 1), a critical enzyme for polyamine biosynthesis, as a druggable target whose inhibition reverses vemurafenib resistance. Metabolomic and proteomic analyses reveal that polyamine biosynthesis is upregulated in vemurafenib-resistant cancer, resulting in enhanced EIF5A hypusination, translation of mitochondrial proteins and oxidative phosphorylation. We also identify that sustained c-Myc levels in vemurafenib-resistant cancer are responsible for elevated polyamine biosynthesis. Finally, inhibition of polyamine biosynthesis or c-Myc reversed vemurafenib resistance both in vitro and in vivo in a xenograft model. With the polyamine biosynthesis signature correlated with poor prognosis in BRAF mutant melanoma patients, our findings reveal that the polyamine-hypusination-mitochondrial respiration pathway is an effective therapeutic target that can maximize the therapeutic efficacy of existing BRAF inhibitors.
2024-07-10 | GSE243344 | GEO
Project description:We report the application of single-molecule-based sequencing technology for high-throughput profiling of RNAs in BRAFV600E+ thyroid cancer cell lines 8505C and WRO. We generated genome-wide transcriptome maps of 8505C and WRO cells after vemurafenib, BRAF inhibitor, treatment. In addition, we generated genome-wide transcriptome maps of clonally selected vemurafenib-resistant 8505C and WRO cells with or without vemurafenib treatment. Negative control treatment was 0.1% of dimethy solfoxide (DMSO), the diluent used to resuspend vemurafenib. The treatment regine of vemurafenib was 2 µM concentration for 24 hours. We find that both inducible response to BRAFi and acquired BRAFi resistance in thyroid cancer cells showed significant activation of the JAK/STAT pathway. Our study demonstrates that the JAK/STAT-signaling pathway is activated as thyroid cancer cells develop resistance to BRAFi and that this pathway is a potential target for anticancer activity and to overcome drug resistance that commonly develops to treatment with BRAFi in thyroid cancer and potentially in other malignancies.
2023-02-16 | GSE178267 | GEO
Project description:Multiple BRAF inhibitor resistance mechanisms have been described, however their relative frequency, clinical correlates, and effect on subsequent therapy have not been assessed in patients with metastatic melanoma. Excised progressing BRAFV600 mutant melanoma metastases (Prog) from patients treated with dabrafenib (n=22) or vemurafenib (n=8) were analyzed for known resistance mechanisms. Oncogenic signaling in Prog and matched pre-treatment tumors was examined using gene expression analysis. Resistance mechanisms were correlated with clinicopathologic features and outcome. A resistance mechanism was identified in 21/38 (55%) Prog samples from 30 patients; BRAF splice variants (n=12, 32%), N-RAS mutations (n=3, 8%), BRAF amplification (n=3, 8%), MEK1/2 mutations (n=3, 8%) and an AKT1 mutation (n=1, 3%). Four Progs tumours displayed multiple resistance mechanisms, and four patients with multiple Progs demonstrated inter-tumoral heterogeneity of resistance mechanisms. Six (21%) of 29 Progs showed loss of MAPK activity by gene expression analysis. These MAPK-inhibited Progs had unknown resistance mechanisms, and these patients had a shorter progression-free survival than patients with MAPK re-activated Progs. There were no responses to subsequent targeted therapy, even when the identified mechanism of resistance was predicted to be responsive. Heterogeneity of resistance mechanisms was common between patients, within patients and within individual tumors. The MAPK pathway remained inhibited in a subset of resistant tumors with unknown mechanisms of resistance, and the outcomes of patients with these tumors are poor. The use of sequential targeted therapies based on the molecular characteristics of a single progressing biopsy is unlikely to provide improved clinical outcomes.
2014-02-19 | GSE50509 | GEO
Project description:Purpose: Identification of miRNAs that enable resistance to BRAF inhibitors in melanoma suggests a mechanism-based strategy to limit resistance and improve clinical outcomes. Methods: We generated A375 melanoma cells resistant to Vemurafenib (VMF) with the goal of investigating changes in miRNA expression patterns that might contribute to resistance. Results: Increased expression of miR-204-5p and miR-211-5p occurring in VMF-resistant cells was determined to impact VMF response.
2018-01-18 | GSE107576 | GEO
Project description:In this report, we generated eight matched pairs of vemurafenib sensitive/resistant melanoma lines and subjected these to concurrent RNA-seq and H3K27Ac ChIP-seq analysis. Globally, we identified two classes of epigenetic profiles that correlate with resistance. Class 1 resistance involves fewer RNA expression alterations accompanied by fewer enhancer mark changes with H3K27Ac. Class 2 resistance shows widespread alterations in transcription and enhancer profiles, which converge on EMT and hypoxia-related pathways. We also observed significant and dynamic changes in super-enhancers that underpin these transcriptomic patterns. We subsequently verified the 2-class structure in pre-BRAFi and post-relapse human melanoma specimens. Our findings reveal a broad and underappreciated spectrum of epigenetic plasticity during acquired BRAFi resistance.
2022-05-25 | GSE203544 | GEO
Project description:BRAF targeted drug vemurafenib have shown very good clinical benefit in melanoma patient containing BRAF V600E mutation. However, resistance always occurs in patient. Early stage of the resistance development require the tumor cell adapted to the targeted drug. We are trying to study the kinetic of melanoma cell adaptation towards vemurafenib. 10 melanoma cell lines with BRAF mutation are treated with targeted therapy vemurafenib. RNA-seq samples are collected after drug treatment for different time (day3 and day21) to compare with DMSO-treated control samples for each cell line. Except innate resistant cell line M381, all other cell lines shows inhibition of proliferation. However, a small cluster of cell lines (M397, M229 and M263) shows some other unique transcriptomic change. For cell line M397, M229 and M263, we also collected the RNA-seq data for long-term (73day/90day) drug treatment condition where the cells developed resistance to vemurafenib treatment. Dedifferentiation is enriched in these unique transcriptomic change within these 3 cell lines. Similar cell state dedifferentiation phenomenon is also reported to cause resistance towards immunotherpay where the resistant de-differentiated melanoma cells are induced by TNF which is secreted by tumor-infiltrating T cells. We also treat our cultured melanoma cells with TNF and collected the treated sample for RNA-seq experiment.
2019-06-22 | E-MTAB-5493 | biostudies-arrayexpress
Project description:In this report, we generated eight matched pairs of vemurafenib sensitive/resistant melanoma lines and subjected these to concurrent RNA-seq and H3K27Ac ChIP-seq analysis. Globally, we identified two classes of epigenetic profiles that correlate with resistance. Class 1 resistance involves fewer RNA expression alterations accompanied by fewer enhancer mark changes with H3K27Ac. Class 2 resistance shows widespread alterations in transcription and enhancer profiles, which converge on EMT and hypoxia-related pathways. We also observed significant and dynamic changes in super-enhancers that underpin these transcriptomic patterns. We subsequently verified the 2-class structure in pre-BRAFi and post-relapse human melanoma specimens. Our findings reveal a broad and underappreciated spectrum of epigenetic plasticity during acquired BRAFi resistance.
2022-05-25 | GSE203545 | GEO