Project description:An improved understanding of the molecular pathogenesis of brain metastases, one of the most common and devastating complications of advanced melanoma, may identify and prioritize rational therapeutic approaches for this disease. In particular, the identification of molecular differences between brain and extracranial metastases would support the need for the development of organ-specific therapeutic approaches. Hotspot mutations, copy number variations (CNV), global mRNA expression patterns, and protein expression and activation, quantitatively analyzed by molecular inversion probe arrays, microarrays and reverse phase protein array (RPPA) were evaluated in pairs of melanoma brain metastases and extracranial metastases from patients who had undergone surgical resection for both types of tumors. Seventy-two samples from 52 brain (except for patient 01, who had a spinal cord metastasis) and extracranial metastases of melanoma were analyzed. Available biological replicates (different parts of the same tumor) were included.
Project description:An improved understanding of the molecular pathogenesis of brain metastases, one of the most common and devastating complications of advanced melanoma, may identify and prioritize rational therapeutic approaches for this disease. In particular, the identification of molecular differences between brain and extracranial metastases would support the need for the development of organ-specific therapeutic approaches. Hotspot mutations, copy number variations (CNV), global mRNA expression patterns, and protein expression and activation, quantitatively analyzed by molecular inversion probe arrays, microarrays and reverse phase protein array (RPPA) were evaluated in pairs of melanoma brain metastases and extracranial metastases from patients who had undergone surgical resection for both types of tumors.
Project description:This is a whole exome study of brain metastases in melanoma. We are studying the genomic evolution of primary cutaneous melanoma to brain met in patients with brain-only metastatic disease. We are also looking at the genomic heterogeneity in patients with temporally, anatomically and regionally separated brian metastases.
Project description:Melanoma brain metastases (MBM) and leptomeningeal metastases (LMM) are two manifestations of melanoma CNS metastasis with vastly different survival outcomes. Using single cell RNA-Seq analysis we uncovered a unique, immune-suppressed T-cell landscape in the LMM microenvironment distinct from that of brain and skin metastases. An LMM patient with an unusually long survival demonstrated an immune repertoire that was distinct from those of poor survivors and more similar to CSF from non-LMM patients. Upon response to PD-1 therapy, this extreme responder showed increased levels of T-cells and dendritic cells in their CSF, whereas poor survivors showed little improvement in their T-cell responses. In MBM patients, systemic therapy was associated with increased immune infiltrate, with similar T-cell transcriptional diversity noted between skin metastases and MBM - suggestive of immune cell trafficking into the brain. A correlation analysis across the entire immune landscape identified the presence of a rare population of dendritic cells (DC3s) that correlated with increased overall survival and positively regulated the immune environment through modulation of activated T-cells and MHC expression. Our study provides the first atlas of two distinct sites of melanoma CNS metastases and identifies rare populations of cells that underlie the biology of this devastating disease.
Project description:An improved understanding of the molecular pathogenesis of brain metastases, one of the most common and devastating complications of advanced melanoma, may identify and prioritize rational therapeutic approaches for this disease. In particular, the identification of molecular differences between brain and extracranial metastases would support the need for the development of organ-specific therapeutic approaches. Hotspot mutations, copy number variations (CNV), global mRNA expression patterns, and protein expression and activation, quantitatively analyzed by mass-array genotyping, molecular inversion probe arrays, microarrays and reverse phase protein array (RPPA) were evaluated in pairs of melanoma brain metastases and extracranial metastases from patients who had undergone surgical resection for both types of tumors. Somatic copy number variation (CNV) in 47 melanoma brain metastases (BM, except for patient 01, who had a spinal cord metastasis) and extracranial metastases (EM) were analyzed by molecular inversion probe (MIP) array (Affymetrix OncoScan FFPE Express 2.0). DNA were extracted from regions with >70% viable tumor cells from formalin-fixed and paraffin-embedded (FFPE) tissues. Of the 47 tumor samples, 22 were matched BM and EM from the same patients. In addition, 24 DNA samples from normal tissues were included as diploid controls.
Project description:An improved understanding of the molecular pathogenesis of brain metastases, one of the most common and devastating complications of advanced melanoma, may identify and prioritize rational therapeutic approaches for this disease. In particular, the identification of molecular differences between brain and extracranial metastases would support the need for the development of organ-specific therapeutic approaches. Hotspot mutations, copy number variations (CNV), global mRNA expression patterns, and protein expression and activation, quantitatively analyzed by mass-array genotyping, molecular inversion probe arrays, microarrays and reverse phase protein array (RPPA) were evaluated in pairs of melanoma brain metastases and extracranial metastases from patients who had undergone surgical resection for both types of tumors.
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.