Project description:Melanoma is one of the deadliest cancers, yet the cells of origin and mechanisms of tumor initiation remain unclear. The majority of melanomas emerge from clear skin without a precursor lesion, but it is unknown whether these melanomas can arise from melanocyte stem cells (MCSCs). Here we employ mouse models to define the role of MCSCs as melanoma cells of origin, demonstrate that MCSC quiescence acts as a tumor suppressor, and identify the extrinsic environmental and molecular factors required for the critical early steps of melanoma initiation. Specifically, melanomas originate from melanoma-competent MCSCs upon stimulation by UVB, which induces MCSC activation and translocation via an inflammation-dependent process. Moreover, the chromatin-remodeling factor Hmga2 in the skin plays a critical role in UVB-mediated melanomagenesis. These findings delineate melanoma formation from melanoma-competent MCSCs following extrinsic stimuli, and they suggest that abrogation of Hmga2 function in the microenvironment can suppress MCSC-originating cutaneous melanomas.
Project description:This SuperSeries is composed of the following subset Series: GSE35387: Expression data from normal melanocyte, melanoma cells and their exosomes (microRNA) GSE35388: Expression data from normal melanocyte, melanoma cells and their exosomes (mRNA) Refer to individual Series
Project description:We investigated the miRNAome in human melanocyte and melanoma cell lines using high-throughput RNA sequencing. We identified a group of dysregulated miRNAs by comparing the miRNA expression profiles among melanoma cell lines. Target genes of these miRNAs participate in functions associated with the cell cycle and apoptosis. Gene networks were built to investigate the interactions of genes during melanoma progression. We identified that the key genes that regulate melanoma cell proliferation were regulated by miRNAs. Our findings provide further knowledge regarding the mechanisms of melanoma development. miRNA profiles of melanocyte (HEMn-LP), low metastatic melanoma (A375) and high metastatic melanoma (A2058) cell line were generated using Illumina GA
Project description:This SuperSeries is composed of the following subset Series: GSE33092: Oncogenic BRAFV600E remodels the melanocyte transcriptome and induces BLNCR1 to regulate melanoma cell migration [HT-seq] GSE37132: Oncogenic BRAFV600E remodels the melanocyte transcriptome and induces BLNCR1 to regulate melanoma cell migration [Affymetrix] Refer to individual Series
Project description:The two most common melanoma histopathologic subtypes, superficial spreading (SSM) and nodular melanoma (NM), are believed to represent sequential phases of linear progression from radial to vertical growth. Studies suggest, however, that SSM and NM are biologically distinct. We utilized an integrative genomic approach to examine the possibility that SSM and NM are the result of independent pathways characterized by unique molecular alterations. Cell lines including SSM, NM, metastatic melanoma, and melanocyte controls were evaluated for copy number changes and differential mRNA expression using single nucleotide polymorphism array (SNP 6.0, Affymetrix) and gene array (U133A 2.0, Affymetrix). Data sets were integrated to identify copy number alterations that correlated with gene expression, and array results were validated using immunohistochemistry on human tissue microarrays (TMAs) and an external data set. The functional effect of genomic deletion was assessed by lentiviral overexpression. Integrative genomics revealed 8 genes in which NM/SSM-specific copy number alterations were correlated with NM/SSM differential gene expression (P<0.05, Spearman’s rank). Pathways analysis of differentially expressed genes (N=114) showed enrichment for metabolic-related processes. SSM-specific genomic deletions (DIS3, MTAP, G3BP2, SEC23IP, USO1) were verified in an expanded panel of cell lines, and forced overexpression of MTAP in SSM resulted in reduced cell growth. Metabolism-related gene ALDH7A1 was verified as overexpressed in NM using human TMAs.The identification of recurrent genomic deletions in SSM not present in NM challenges the linear model of melanoma progression and supports the unique molecular classification of SSM and NM. Gene expression profiling using Affymetrix U133A 2.0 arrays was performed on 18 melanoma cell lines including 2 primary superficial spreading melanoma, 2 primary nodular melanoma, 2 metastatic nodular melanoma, and 12 metastatic cell lines. Four melanocyte control lines were also evaluated including 2 immortalized melanocyte cell lines (Hermes 1 and 2B) and 2 normal melanocyte lines cultured from neonatal foreskin (HEM-N and HEM-LP).
Project description:We compared the gene signatures of mouse melanocyte stem cells and the melanoma tumor derived from them upon Braf V600E mutation and loss of Pten, as well as the heterogeneity of the melanoma cells by single cell RNAseq
Project description:Ultraviolet radiation (UV) is causally linked to cutaneous melanoma, yet the underlying epigenetic mechanisms, known as molecular sensors of exposure, have never been characterized in clinical biospecimen. DNA methylome, genome and transcriptome analyses of cutaneous melanoma in two cohorts identified UV-related alterations in regulatory regions and immunological pathways and revealed novel cancer driver genes affecting patient survival. TAPBP, the top gene and a member of the immunoglobulin superfamily, encompassed several CpG methylation sites altered by UV and independently validated by bisulfite pyrosequencing, providing cost-effective opportunities for clinical application. The DNA methylome also highlighted non UV-related aberrations underlying pathological differences between cutaneous and acral melanomas. Unsupervised epigenomic mapping demonstrated that non UV-mutant cutaneous melanoma more closely resembles acral rather than UV-exposed cutaneous melanoma, with the latter showing better patient prognosis than the other two forms. These gene-environment interactions in multi-ethnic backgrounds reveal translationally impactful mechanisms in melanomagenesis.
Project description:Nucleotide excision repair (NER) orchestrates the repair of helix distorting DNA damage, induced by both ultraviolet radiation (UVR) and cisplatin. There is evidence that the global genome repair (GGR) arm of NER is dysfunctional in melanoma and it is known to have limited induction in melanoma cell lines after cisplatin treatment. The aims of this study were to examine mRNA transcript levels of regulators of GGR and to investigate the downstream effect on global transcript expression in melanoma cell lines after cisplatin treatment and in melanoma tumours. One melanocyte, three primary melanoma (MM200, IgR3, Me4405) and two metastatic melanoma (Mel-RM and Sk-mel-28) cell lines were treated with cispltain and gene expression profile data collected at 0, 6 and 24 hours. Biological duplicates were treated and RNA was collected for each cell line at each timepoint. The duplicated were run sperately on the WGGEX beadarrays and the results of the duplicates averaged for publication. The transcript expression results were cubic spline normalised using BeadStudio 2.0 software (Illumina, USA), and the remaining analyses was performed using GeneSpring GX 11.0. To account for bias or skewing of expression results all the gene expression profiles and each individual gene were normalized to the median resulting in two way normalisation. For visualisation of the results the data was log transformed.
Project description:We investigated the miRNAome in human melanocyte and melanoma cell lines using high-throughput RNA sequencing. We identified a group of dysregulated miRNAs by comparing the miRNA expression profiles among melanoma cell lines. Target genes of these miRNAs participate in functions associated with the cell cycle and apoptosis. Gene networks were built to investigate the interactions of genes during melanoma progression. We identified that the key genes that regulate melanoma cell proliferation were regulated by miRNAs. Our findings provide further knowledge regarding the mechanisms of melanoma development.