Project description:Whole Exome Sequencing of cohorts of Mutant Braf mouse model melanoma DNA and germline DNA. The cohorts are (1) Mutant Braf mouse model melanomas, (2) Mutant Braf mouse model melanomas from UVR exposed mice and (3) Mutant Braf mouse model melanomas from UVR exposed, sunscreen protected mice.
Project description:We investigated copy number alterations in melanomas from two cohorts of Braf mutant mice (UV exposed and no UV exposure) by comparing tumour DNA to germline DNA by array CGH
Project description:Melanoma cell lines were assessed for differences in gene expression patterns between the lines sensitive and resistant to BRAF and MEK inhibitor drugs. 22 BRAF-mutant melanoma cell lines were assessed for response to BRAF and MEK inhibitors in a 3 day drug treatment dose response assay. Based on the IC50, 18 lines were found to be responsive to BRAF or MEK inhibition and 4 were resistant. Normalised gene expression data generated from experimental replicate affymetrix arrays was assessed to identify differential patterns of inherent gene expression between the cell lines grouped as drug-responsive or drug-resistant. This were used to idenify specific candidate genes and pathways associated with inherent BRAF/MEK inhibitor drug resistance in melanoma cells.
Project description:We investigated copy number alterations in melanomas from two cohorts of Braf mutant mice (UV exposed and no UV exposure) by comparing tumour DNA to germline DNA by array CGH There were 15 tumour samples in each cohort (UV exposed and no UV exposure)
Project description:Melanoma cell lines were assessed for differences in gene expression patterns between the lines sensitive and resistant to BRAF and MEK inhibitor drugs.
Project description:Whole-exome sequencing was performed on DNA sample extracted from one melanoma cell line resistant to vemurafenib (BRAF V600E inhibitor). The aim of the experiment was to search for genetic alterations responsible for phenotypic diversity of melanoma cell lines reported at the level of cell morphology, activity of signaling pathways essential for melanoma development and progression, and resistance to targeted therapeutics.
Project description:Melanoma patients carry a high risk of developing brain metastases, and improvements in survival are still measured in weeks or months. Durable disease control within the brain is impeded by poor drug penetration across the blood-brain barrier, as well as intrinsic and acquired drug resistance. In this study, we used high-throughput pharmacogenomic profiling to identify potentially repurposable compounds against BRAF-mutant melanoma brain metastases. One of the compounds identified was β-sitosterol, a well-tolerated and brain-penetrable phytosterol. We found that β-sitosterol attenuated melanoma cell growth in vitro and significantly inhibited brain metastasis in vivo. Large-scale phosphoproteomic and in silico analyses indicated that the therapeutic potential of β-sitosterol was linked to mitochondrial interference. Mechanistically, β-sitosterol effectively reduced mitochondrial respiration and respiratory capacity in melanoma cells, mediated by a selective inhibition of mitochondrial complex I. This led to increased oxidative stress and apoptosis. Notably, we observed completely abrogated BRAF inhibitor resistance when vemurafenib was combined with either β-sitosterol or a functional knockdown of mitochondrial complex I. Based on its favorable tolerability, excellent brain bioavailability, and capacity to inhibit mitochondrial respiration, β-sitosterol represents a promising candidate for drug repurposing in patients with, or at risk for, melanoma brain metastases.
Project description:Whole-exome sequencing was performed on DNA samples extracted from seven melanoma cell lines resistant to either vemurafenib (BRAF V600E inhibitor) or trametinib (MEK1/2 inhibitor). The aim of the experiment was to search for genetic alterations responsible for phenotypic diversity of melanoma cell lines reported at the level of cell morphology, activity of signaling pathways essential for melanoma development and progression, and resistance to targeted therapeutics.
Project description:Whole-exome sequencing was performed on DNA samples extracted from seven melanoma cell lines resistant to either vemurafenib (BRAF V600E inhibitor) or trametinib (MEK1/2 inhibitor). The aim of the experiment was to search for genetic alterations responsible for phenotypic diversity of melanoma cell lines reported at the level of cell morphology, activity of signaling pathways essential for melanoma development and progression, and resistance to targeted therapeutics.
Project description:Preclinical and clinical data implicate the transcriptional co-activator YAP1 in resistance to multiple targeted therapies, including BRAF and MEK inhibitors. However, tumor subtypes driven by YAP1 activity and associated vulnerabilities are poorly defined. Here, we show particularly high YAP1 activity in the MITFlow/AXLhigh subset of melanoma cell lines and patient tumors characterized by resistance to MAPK pathway inhibition and broad receptor tyrosine kinase activity. To uncover genetic dependencies of melanoma cells with high YAP1 activity, we used a genome-wide CRISPR/Cas9 functional screen and identified SLC35B2, the 3′-phosphoadenosine-5′-phosphosulfate transporter of the Golgi apparatus, as an essential gene for YAP1-mediated drug resistance. SLC35B2 expression correlates with tumor progression, and its loss decreases heparan sulfate expression, reduces receptor tyrosine kinase activity, and sensitizes resistant melanoma cells to BRAF inhibition in vitro and in vivo. Thus, SLC35B2 is a target in YAP1-driven BRAF mutant melanoma for overcoming drug resistance to MAPK pathway inhibitors.
