Project description:Analysis of the functional significance of peptide-N(4)-(N-acetyl-beta-glucosaminyl)asparagine amidase in human melanoma cells. The hypothesis tested in the present study was that this glycosidase may be involved in melanoma development.
Project description:This study explored the role of targeting protein for Xklp2 (TPX2), located with 20q11.2, in melanoma pathogenesis, based on initial findings that it was commonly gained and overexpressed. TPX2 copy number was evaluated in melanoma cell lines compared to control DNA. Thrity-three cell lines were analyzed by Agilent SurePrint G3 Human CGH Microarray 2x400K. Samples were compared to Human Female DNA from Promega.
Project description:This study explored the role of targeting protein for Xklp2 (TPX2), located with 20q11.2, in melanoma pathogenesis, based on initial findings that it was commonly gained and overexpressed. TPX2 copy number was evaluated in melanoma cell lines compared to control DNA.
Project description:Differential gene expression analysis of parental and resistant sub-lines of melanoma cell lines treated or untreated with PLX4032 Using microarray we sought to obtain a genome-wide profile of differentially expressed genes in parental melanoma cell lines and resistant sub-lines in response to PLX4032 vs DMSO control treatment.
Project description:The imbalance of cellular homeostasis during oncogenesis together with the high heterogeneity of tumor-associated stromal cells have a marked effect on the repertoire of the proteins secreted by malignant cells (the secretome). Hence, the study of tumoral secretomes provides insights for understanding the cross-talk between cells within the tumor microenvironment as well as the key effectors for the establishment of the pre-metastatic niche in distant tumor sites. In this context, we performed a proteomic analysis of the secretomes derived from four cell lines: (i) a paired set of fibroblasts - Hs 895. T, a cell line obtained from a lung node metastatic site from a patient who had melanoma and Hs 895.Sk, a skin fibroblast cell line (derived from the same patient); (ii) two malignant metastatic melanoma cell lines - A375, a malignant melanoma cell line from primary source and SH-4, a cell line derived from pleural effusion of a patient with metastatic melanoma. Clustering of expression profiles together with functional enrichment revealed patterns that mirrored each cell type (skin fibroblasts, cancer-associated fibroblasts and metastatic cells). These patterns might be the result of cell-specific protein expression programs and may serve as basis for further proteomic analysis of melanoma cell lines secretomes.
Project description:Melanoma is an aggressive neoplasm with increasing incidence that is classified by the NCI as a recalcitrant cancer, i.e., a cancer with poor prognosis, lacking progress in diagnosis and treatment. In addition to conventional therapy, melanoma treatment is currently based on targeting the BRAF/MEK/ERK signaling pathway and immune checkpoints. As drug resistance remains a major obstacle to treatment success, advanced therapeutic approaches based on novel targets are still urgently needed. We reasoned that the base excision repair enzyme Thymine DNA Glycosylase (TDG) could be such a target for its dual role in safeguarding the genome and the epigenome, by performing the last of the multiple steps in DNA demethylation. Here we show that TDG knockdown in melanoma cell lines causes cell cycle arrest, senescence and death by mitotic alterations, alters the transcriptome and methylome, and impairs xenograft tumor formation. Importantly, untransformed melanocytes are minimally affected by TDG knockdown, and adult mice with conditional knockout of Tdg are viable. Candidate TDG inhibitors, identified through a high-throughput fluorescence-based screen, reduced viability and clonogenic capacity of melanoma cell lines and increased cellular levels of 5-carboxylcytosine, the last intermediate in DNA demethylation, indicating successful on-target activity. These findings suggest that TDG may provide critical functions specific to cancer cells that make it a highly suitable anti-melanoma drug target. By potentially disrupting both DNA repair and the epigenetic state, targeting TDG may represent a completely new approach to melanoma therapy.
Project description:To investigate mechanisms of resistance to BRAF inhibitor therapy in melanoma, BRAF mutant cell lines have been chronically exposed to BRAFi to create phenotypes with acquired drug resistance. Activity-based protein profiling with desthiobiotinylating ATP probes (ActivX, Thermo) is used to examine the differences between naive and drug-resistant cells.
Project description:Previous work identified RMEL3 as a lncRNA with enriched expression in melanoma. Analysis of The Cancer Genome Atlas (TCGA) data confirmed RMEL3 enriched expression in melanoma and demonstrated its association with the presence of BRAFV600E. RMEL3 siRNA-mediated silencing markedly reduced (95%) colony formation in different BRAFV600E melanoma cell lines. Multiple genes of the MAPK and PI3K pathways found to be correlated with RMEL3 in TCGA samples were experimentally confirmed. RMEL3 knockdown led to downregulation of activators or effectors of these pathways, including FGF2, FGF3, DUSP6, ITGB3 and GNG2. RMEL3 knockdown induces gain of protein levels of tumor suppressor PTEN and the G1/S cyclin-Cdk inhibitors p21 and p27, as well as a decrease of pAKT (T308), BRAF, pRB (S807, S811) and cyclin B1. Consistently, knockdown resulted in an accumulation of cells in G1 phase and subG0/G1 in an asynchronously growing population. Thus, TCGA data and functional experiments demonstrate that RMEL3 is required for MAPK and PI3K signaling, and its knockdown decrease BRAFV600E melanoma cell survival and proliferation.