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:Testicular germ cell tumors (TGCTs) are uniquely curable with cisplatin-based therapies even when widely metastatic, however cisplatin resistance does occur resulting in very poor prognosis. The mechanisms to explain TGCT hypersensitivity to cisplatin and mechanisms of resistance are not well understood. The global transcriptional response to acute cisplatin treatment (24 hours after a 6-hour pulse of cisplatin) was assessed in three parental embryonal carcinoma TGCT cells lines compared to multiple isogenic, stable, cisplatin-resistant clonal lines from these pa-rental cells. Cisplatin treatment of parental cells consistently showed a more robust overall transcriptional response to cisplatin compared to their cisplatin-resistant cellular counterparts for a common set of genes and pathways including the upregulation of genes associated with histone modifications and p53, EMT, and KRAS signaling and the downregulation of genes normally upregulated by MYC. Focusing on genes exclusively altered in parental cells revealed upregulated genes known to be induced by p53 and downregulated by MYC and the transferrin receptor, TFRC1. Several of these p53/MYC/TFRC1 targets were associated with a higher instance of disease free survival in a cohort of TGCT patients. Cisplatin resistance in TGCT cells is associated with a diminished alteration of cisplatin responsive genes especially genes known the be regulated by p53, MYC and TFRC1 that may be linked to cisplatin hypersensitivity and survival in TGCTs.
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: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: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.