Project description:The development of chemo-resistance has dramatically limited the clinical efficiency of platinum-based therapy. Although many resistant mechanisms have been demonstrated, genetic/molecular alterations responsible for drug resistance in the majority of clinical cases has not been identified. We analyzed three pairs of testicular germ cell tumor (TGCT) cell lines using Affymetrix expression microarrays to identify differential expressed genes. Then the expression of CCND1/CyclinD1, selected from the microarray analysis, was determined in cisplatin sensitive and resistance cancer samples including TGCTs, ovarian and prostate cancers by quantitative reverse transcription PCR analysis (qRT-PCR). Finally, we determined the gene knocked-down effect of CyclinD1. Expression microarray study revealed a limited number of differentially expressed genes across all three cell lines when comparing the parental and resistant cells. Among them, CyclinD1 was the most significantly differentially expressed gene. Importantly, we found that, in clinical TGCT samples, the overall expression level of cyclinD1 is higher in resistant cases compared to those sensitive samples (9/12 in the resistant group and only 3/8 in the sensitive group). We also found that cyclinD1 expressed dozens of fold higher in the resistant than in the sensitive ovarian cancer cell lines and dramatically overexpressed in prostate cancer. We re-sensitized the resistant cells by knocking-down cyclinD1. We demonstrated that deregulation of cyclinD1 is the major cause of TGCT cisplatin resistance and it may also be commonly involved in other human cancers. Combined cyclinD1 inhibition and cisplatin chemotherapy may be used clinically to treat the large number of cyclinD1 deregulated resistant tumors. RNA from three paired parental and cisplatin-resistant TGCT cell lines was extracted and analysed by Affymetrix gene expression microarray profiling (Human Genome U133 plus 2.0 arrays). Expression changes associated with the resistant phenotype were identified by comparing the three cisplatin-resistant derivatives to their parental counterparts.
Project description:To clarify the mechanism of cisplatin resistance in testicular germ cell tumor (TGCT), cisplatin-resistant TGCT cells (N8R and G9R) were generated from parental NEC8 cells (N8P) and TGCT patient-derived cells (TGCT-PDC)(G9P), respectively, by culture in medium containing cisplatin. We used microarrays to detail the global programme of gene expression underlying cisplatin resistance and identified up- and down-regulated genes during this process.
Project description:The development of chemo-resistance has dramatically limited the clinical efficiency of platinum-based therapy. Although many resistant mechanisms have been demonstrated, genetic/molecular alterations responsible for drug resistance in the majority of clinical cases has not been identified. We analyzed three pairs of testicular germ cell tumor (TGCT) cell lines using Affymetrix expression microarrays to identify differential expressed genes. Then the expression of CCND1/CyclinD1, selected from the microarray analysis, was determined in cisplatin sensitive and resistance cancer samples including TGCTs, ovarian and prostate cancers by quantitative reverse transcription PCR analysis (qRT-PCR). Finally, we determined the gene knocked-down effect of CyclinD1. Expression microarray study revealed a limited number of differentially expressed genes across all three cell lines when comparing the parental and resistant cells. Among them, CyclinD1 was the most significantly differentially expressed gene. Importantly, we found that, in clinical TGCT samples, the overall expression level of cyclinD1 is higher in resistant cases compared to those sensitive samples (9/12 in the resistant group and only 3/8 in the sensitive group). We also found that cyclinD1 expressed dozens of fold higher in the resistant than in the sensitive ovarian cancer cell lines and dramatically overexpressed in prostate cancer. We re-sensitized the resistant cells by knocking-down cyclinD1. We demonstrated that deregulation of cyclinD1 is the major cause of TGCT cisplatin resistance and it may also be commonly involved in other human cancers. Combined cyclinD1 inhibition and cisplatin chemotherapy may be used clinically to treat the large number of cyclinD1 deregulated resistant tumors.
Project description:Type II testicular germ cell tumors (TGCT) are the most prevalent tumors in young men. Patients suffering from cisplatin resistant TGCTs are facing very poor prognosis demanding novel therapeutic options. Neddylation is a known posttranslational modification mediating many important biological processes including tumorigenesis. Overactivation of neddylation pathway promotes carcinogenesis and tumor progression in various entities by inducing proteasomal degradation of tumor suppressors (e.g., p21, p27). We used a genome-scale CRISPR/Cas9 activation screen to identify cisplatin resistance factors. TGCT cell lines were treated with the neddylation inhibitor (MLN4924)/cisplatin/combination and investigated for changes in viability (XTT assay), apoptosis/cell cycle (flow cytometry) as well as in the transcriptome (3’mRNA sequencing). NAE1 overexpression was detected in cisplatin resistant colonies from the CRISPR screen. Inhibition of neddylation using MLN4924 increased cisplatin cytotoxicity in TGCT cell lines and sensitized cisplatin resistant cells towards cisplatin. Apoptosis, G2/M-phase cell cycle arrest, gH2A.X/P27 accumulation and mesoderm/endoderm differentiation was observed in TGCT cells while fibroblast cells were unaffected. We identified overactivation of neddylation as a factor for cisplatin resistance in TGCTs and highlighted the additive effect of NAE1 inhibition by MLN4924 in combination with cisplatin as a novel treatment option for TGCTs.
Project description:Type II testicular germ cell tumors (TGCT) are the most prevalent tumors in young men. Patients suffering from cisplatin resistant TGCTs are facing very poor prognosis demanding novel therapeutic options. Neddylation is a known posttranslational modification mediating many important biological processes including tumorigenesis. Overactivation of neddylation pathway promotes carcinogenesis and tumor progression in various entities by inducing proteasomal degradation of tumor suppressors (e.g., p21, p27). We used a genome-scale CRISPR/Cas9 activation screen to identify cisplatin resistance factors. TGCT cell lines were treated with the neddylation inhibitor (MLN4924)/cisplatin/combination and investigated for changes in viability (XTT assay), apoptosis/cell cycle (flow cytometry) as well as in the transcriptome (3’mRNA sequencing). NAE1 overexpression was detected in cisplatin resistant colonies from the CRISPR screen. Inhibition of neddylation using MLN4924 increased cisplatin cytotoxicity in TGCT cell lines and sensitized cisplatin resistant cells towards cisplatin. Apoptosis, G2/M-phase cell cycle arrest, gH2A.X/P27 accumulation and mesoderm/endoderm differentiation was observed in TGCT cells while fibroblast cells were unaffected. We identified overactivation of neddylation as a factor for cisplatin resistance in TGCTs and highlighted the additive effect of NAE1 inhibition by MLN4924 in combination with cisplatin as a novel treatment option for TGCTs.
Project description:Cisplatin resistance is a problem in cancer treatment. Using DNA microarray, we detected differentially expressed genes in cisplatin-resistant cervix carcinoma HeLa cells compared to parental cells. Three cisplatin resistant cell lines were established by stepwise increasing cisplatin concentration. RNA from these resistant lines and its parental HeLa cells were labeled with Cy5 and Cy3. Equal amount of RNA from resistant cell line and HeLa were mixed and were hybridized to cDNA array. Signals were scanned and analyzed to find out the candidate genes involved in cisplatin resistant mechanism.
Project description:A greater understanding of the hypersensitivity and curability of testicular germ cell tumors (TGCTs) has the potential to inform strategies to sensitize other solid tumors to conventional chemotherapies. More than 80% of metastatic TGCT patients are cured with cisplatin-based chemotherapy. However, resistance can occur, which results in poor outcomes. The mechanisms of cisplatin hypersensitivity and resistance in these tumors and embryonal carcinoma (EC), the stem cells of TGCTs, remain largely undefined. To study the mechanisms of cisplatin acquired resistance we generated a large panel of independently derived, acquired resistant clones from three distinct parental EC models employing a protocol designed to match standard of care regimens of TGCT patients. Transcriptomics revealed highly significant alterations shared between resistant cells regardless of their parental origin. This included a highly significant enrichment of genes normally repressed by H3K27 methylation and the polycomb repressive complex 2 (PRC2) which correlated with a substantial decrease in global H3K27me3, H2AK119 ubiquitination and expression of BMI1. Importantly repression of H3K27 methylation with the EZH2 inhibitor GSK-126 conferred cisplatin resistance to parental cells while induction of H3K27 methylation with the histone lysine demethylase inhibitor GSK-J4 resulted in increased cisplatin sensitivity to resistant cells. A gene signature based on H3K27me gene enrichment was associated with an increased rate of recurrent/progressive disease in testicular cancer patients. Our data indicates that repression of H3K27 methylation may be a mechanism of cisplatin acquired resistance in TGCTs and that restoration of PRC2 complex function could be a viable approach to overcome treatment failure.
Project description:Genome wide DNA methylation profiling of paired parental and therapy resistant cancer cell lines. Parental cell lines are mostly established cell lines. Resistant cell lines were obtained through long term exposure of the parental cells to gradually increasing doses of cancer therapies. The Illumina Infinium 450k and EPIC Human DNA methylation Beadchips were used to obtain DNA methylation profiles across approximately 450,000 or 850,000 CpGs from the cells. Samples include 7 parental and 10 derived resistant cell lines.
Project description:Testicular germ cell tumors (TGCTs) can be treated with cisplatin-based therapy. However, a clinically significant number of cisplatin-resistant patients die from progressive disease as no effective alternatives exist. Curative cisplatin therapy results in acute and life-long toxicities in the young TGCT patient population providing a rationale to decrease cisplatin exposure. In contrast to genetic alterations, recent evidence suggests that epigenetics is a major driving factor for TGCT formation, progression, and response to chemotherapy. Hence, targeting epigenetic pathways with “epidrugs” is one potential relatively unexplored strategy to advance TGCT treatment beyond cisplatin. In this report, we demonstrate for the first time that targeting polycomb demethylases KDM6A and KDM6B with epidrug GSK-J4 can treat both cisplatin-sensitive and -resistant TGCTs. While GSK-J4 had minimal effects alone on TGCT tumor growth in vivo, it dramatically sensitized cisplatin-sensitive and -resistant TGCTs to cisplatin. We validated KDM6A/KDM6B as the target of GSK-J4 since KDM6A/KDM6B genetic depletion had a similar effect to GSK-J4 on cisplatin-mediated anti-tumor activity and transcriptome alterations. Pharmacologic and genetic targeting of KDM6A/KDM6B potentiated or primed the p53-dominant transcriptional response to cisplatin, with also evidence for basal activation of p53. Further, several chromatin modifier genes, including BRD4, lysine demethylases, chromodomain helicase DNA binding proteins, and lysine methyltransferases, were repressed with cisplatin only in KDM6A/KDM6B-targeted cells, implying that KDM6A/KDM6B inhibition sets the stage for extensive chromatin remodeling of TGCT cells upon cisplatin treatment. Our findings demonstrate that targeting polycomb demethylases is a new potent pharmacologic strategy for treating cisplatin resistant TGCTs that warrants clinical development.
Project description:Cisplatin is a broad-spectrum anticancer drug, which is estimated to be administered to 40-80% of patients undergoing chemotherapy. However, its clinical utility is often limited due to factors that include acquired resistance of cancer cells to cisplatin. Because cisplatin is currently evaluated as a prospective agent for combined chemotherapy of pancreatic ductal adenocarcinoma (PDAC), we have investigated mechanisms involved in the acquired resistance of PDAC cells to cisplatin using gene expression study of two different parental-resistant pairs of PDAC cell lines. We have developed cisplatin-resistant cell lines AsPC1-R and BxPC3-R from their parental PDAC cell lines AsPC1 and BxPC3, respectively, by culturing them in medium with step-wise increasing concentration of cisplatin. Parental and resistant pairs of PDAC cells were analyzed by whole-transcript gene expression analysis.