Cisplatin treated melanoma and melanocyte cell lines
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ABSTRACT: 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: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.
Project description:Deficient DNA repair capacity is associated with genetic lesions accumulation and susceptibility to carcinogenesis. MicroRNAs (miRNAs) are small non-coding RNAs that regulate various cellular pathways including DNA repair. Here we hypothesized that the existence of HBV products may interfere with cellular nucleotide excision repair (NER) through microRNA-mediated gene regulation. We found that NER was impaired in HepG2.2.15 cells, a stable HBV-expressing cell line, compared with its parental cell line HepG2. Altered miRNA expression profile, in particular the significant upregulation of miR-192, was observed in HepG2.2.15 cells. Additionally, ERCC3 and ERCC4, two key factors implicated in NER, were identified as targets of miR-192 and over-expressing miR-192 significantly inhibited cellular NER. These results indicated that persistent HBV infection might trigger NER impairment in part through upregulation of miR-192, which suppressed the levels of ERCC3 and ERCC4. It provides new insight into the effect of chronic HBV infection on NER and genetic instability in cancer. A genome-wide miRNAs microarray was performed to identify differentially expressed miRNAs between HepG2.2.15, a stable HBV-expressing cell line, and its parental cell line HepG2.
Project description:The dominant genetic signature found in melanoma is C to T mutations due to UV radiation. Nucleotide excision repair (NER) recognises and repairs UV-induced DNA damage. We aimed to determine the effect of high UV exposure on the melanoma transcriptome and key NER transcripts in melanoma tumours in association with clinical and genetic features of the disease. 196 primary or metastatic melanomas were utilised for this study. Solar elastosis and transcriptome data was collected. mRNA transcript levels of NER components XPC, DDB1 and DDB2 were quantified and compared to clinical parameters. Solar elastosis negatively correlated with Breslow thickness (-0.251, p=0.017) and was significantly lower in BRAFV600E melanomas. Lower XPC expression was associated with BRAFV600E and NRASQ61R mutations, earlier age of diagnosis and poorer survival. Transcriptome profiling identified an over-representation of DNA repair processes in high vs low solar elastosis. Further analysis revealed DNA repair and kinase activity related transcripts in the low XPC melanomas. XPC deficiency is associated with the presence of kinase mutations and an aggressive disease phenotype, both of which result from the hypermutability of melanoma.
Project description:The therapeutical efficacy of cisplatin and oxaliplatin depends on the balance between the DNA damage induction and the DNA damage response of tumor cells. Based on clinical evidence, oxaliplatin is administered to cisplatin-unresponsive cancers, but the underlying molecular causes for this tumor specificity are not clear. Hence, stratification of patients based on DNA repair profiling is not sufficiently utilized for treatment selection. Using a combination of genetic, transcriptomic and imaging approaches, we identified factors that promote global genome nucleotide excision repair (GG-NER) of DNA-platinum adducts induced by oxaliplatin, but not by cisplatin. We show that oxaliplatin-DNA lesions are a poor substrate for GG-NER initiating factor XPC and that DDB2 and HMGA2 are required for efficient binding of XPC to oxaliplatin lesions and subsequent GG-NER initiation. Loss of DDB2 and HMGA2 therefore leads to hypersensitivity to oxaliplatin but not to cisplatin. As a result, low DDB2 levels in different colon cancer cells are associated with GG-NER deficiency and oxaliplatin hypersensitivity. Finally, we show that colon cancer patients with low DDB2 levels have a better prognosis after oxaliplatin treatment than patients with high DDB2 expression. We therefore propose that DDB2 is a promising predictive marker of oxaliplatin treatment efficiency in colon cancer.
Project description:Little is known about genes that promote melanoma cell growth and proliferation. siRNAs may be used to address the role of individual genesin these processes. RNAi library screens were used in the past to gain a comprehensive overview of all genes involved in cell growth, proliferation, migration and other cellular processes. A large-scale loss-of-function screen for eight different melanoma cell lines was performed using a pooled lentiviral shRNA library (GeneNet Human 50K lentiviral shRNA Library,cat#SI206B-1, System Biosciences) to identify genes relevant for melanoma cell growth and proliferation. shRNAs that lead to cell death or reduced growth of transduced melanoma cells are negatively selected and thereby underrepresented in the final cellular shRNA pool and vice versa. The shRNAs of the shRNA library (3-5 per gene) have complementary sequences to probes on the custom Affymetrix microarray HG-U133Plus2 and were analysed using this array. Well-known melanoma cell lines SK-Mel-103, A375, SK-Mel-147, SK-Mel-19, SK-Mel-28, SK-Mel-29, SK-Mel-5, WM3523cln6 were transduced with the lentiviral shRNA library and grown for 10 days under puromycin selection (day 10), control cells of respective cell lines were transduced and frozen immediately after transduction and genomic integration of shRNAs (day 0). Totel DNA was extracted and genomically integrated shRNAs were hybridized to Affymetrix microarrays (HG-U133Plus2.0 array).
Project description:Expression .CEL files from Affymetrix HG-U133A 2.0 arrays using DNA from 14 human cell lines derived from metastasized melanoma Study of global gene expression differences in malignant melanoma cell lines with or without specific abberations in BRAF NRAS or CDKN2A. UKRV-Mel-16a was wrongly described as Ma-Mel-16a in Blöthner et al. 2005
Project description:Purpose: Assess the transcriptional changes induced upon RAB7 knock-down in melanoma (SK-Mel-28 and UACC-62) and in colon cancer (HCT-116) cell lines. Methods: mRNA profiles of tumor cell lines (SK-Mel-28, UACC-62, HCT-116) stably expressing scrambled shRNA or RAB7 shRNA (harvested at day 3 after lentiviral infection) were generated by deep sequencing, using three biological replicates per condition. The sequence reads that passed quality filters were analyzed with TopHat and Cufflinks. Validation of induced / silenced genes was performed by western blot. Results show a differential impact of RAB7 expression in the transcriptomic profile of melanoma vs non-melanoma cell lines, and support a lineage-specific role of this small GTPase in melanoma. Examination of the mRNA profiles RAB7-depleted vs wild type cells, performed in parallel in 3 different tumor cell lines (Melanomas: SK-Mel-28 and UACC-62, Non-melanoma: HCT-116) harvested at day 3 after lentiviral infection.
Project description:Homologous recombination (HR) and nucleotide excision repair (NER) are the two most frequently disabled DNA repair pathways in cancer. HR-deficient breast, ovarian, pancreatic and prostate cancers respond well to platinum chemotherapy and PARP inhibitors. However, the frequency of HR deficiency in gastric and esophageal adenocarcinoma (GEA) still lacks diagnostic and functional validation. Using whole exome and genome sequencing data, we found that a significant subset of GEA, but very few colorectal adenocarcinomas, show evidence of HR deficiency by mutational signature analysis (HRD score). High HRD gastric cancer cell lines demonstrated functional HR deficiency by RAD51 foci assay and increased sensitivity to platinum chemotherapy and PARP inhibitors. Of clinical relevance, analysis of three different GEA patient cohorts demonstrated that platinum treated HR deficient cancers had better outcomes. A gastric cancer cell line with strong sensitivity to cisplatin showed HR proficiency but exhibited NER deficiency by two photoproduct repair assays. Single-cell RNA-sequencing revealed that, in addition to inducing apoptosis, cisplatin treatment triggered ferroptosis in a NER-deficient gastric cancer, validated by intracellular GSH assay. Overall, our study provides preclinical evidence that a subset of GEAs harbor genomic features of HR and NER deficiency and may therefore benefit from platinum chemotherapy and PARP inhibitors.
Project description:One of the components of the tumor progression of melanoma of the skin is the formation of drug resistance. Chemotherapeutic agents can affect the cell cycle, DNA repair. By influencing melanoma cells of the BRO and SK-MEL-2 lines, the effect of a cytostatic drug on the genomic profile was determined
Project description:The rates at which lesions are removed by DNA repair can vary widely throughout the genome with important implications for genomic stability. We measured the distribution of nucleotide excision repair (NER) rates for UV induced lesions throughout the yeast genome. By plotting these repair rates in relation to all ORFs and their associated flanking sequences, we reveal that in normal cells, genomic repair rates display a distinctive pattern, suggesting that DNA repair is highly organised within the genome. We compared genome-wide DNA repair rates in wild type and in RAD16 deleted cells, which are defective in the global genome-NER (GG-NER) sub-pathway, demonstrating how this alters the normalâ¨distribution of NER rates throughout the genome. We examine the genomic locations of global genome NER factor binding in chromatin before and after UV irradiation, and reveal that GG-NER is organized and initiated from specific locations. By controlling the chromatin occupancy of the histone acetyl transferase Gcn5, the GG-NER complex regulates the histone H3 acetylation status and chromatin structure in the vicinity of these genomic sites to promote the efficient DNA repair of UV induced lesions. This demonstrates that chromatin remodeling during the GG-NER process is organized into domains in the genome. Importantly, we demonstrate that deleting the histone modifier GCN5, an accessory factor required for chromatin remodeling during GG-NER, significantly alters the genomic distribution of NER rates. These observations could have important implications for the effect of histone and chromatin modifiers on the distribution of genomic mutations acquired throughout the genome.