Project description:Drug resistance poses a major challenge to ovarian cancer treatment. Understanding mechanisms of drug resistance is important for finding new therapeutic targets. In the present work, a cisplatin-resistant ovarian cancer cell line A2780-DR was established with a resistance index of 6.64. The cellular accumulation of cisplatin was significantly reduced in A2780-DR cells as compared to A2780 cells consistent with the general character of drug resistance. Quantitative proteomic analysis identified 340 differentially expressed proteins between A2780 and A2780-DR cells, which involve in diverse cellular processes, including metabolic process, cellular component biogenesis, cellular processes and stress responses. Expression levels of Ras-related proteins Rab 5C and Rab 11B in A2780-DR cells were lower than those in A2780 cells as confirmed by real-time quantitative PCR and western blotting. The short hairpin (sh)RNA-mediated knockdown of Rab 5C in A2780 cells resulted in markedly increased resistance to cisplatin whereas overexpression of Rab 5C in A2780-DR cells increases sensitivity to cisplatin, demonstrating that Rab 5C-dependent endocytosis plays an important role in cisplatin resistance. Our results also showed that expressions of glycolytic enzymes PKM, GPI, Aldolase, LDH, and PGK were down-regulated in drug resistant cells, indicating drug resistance in ovarian cancer is directly associated with a decrease in glycolysis. Furthermore, it was found that glutathione reductase were up-regulated in A2780-DR, while vimentin, HSP90, and Annexin A1 and A2 were down-regulated. Taken together, our results suggest that drug resistance in ovarian cancer cell line A2780 is caused by multifactorial traits, including the down-regulation of Rab 5C-dependent endocytosis of cisplatin, glycolytic enzymes and vimentin, and up-regulation of antioxidant proteins, suggesting Rab 5C is a potential target for treatment of drug-resistant ovarian cancer. This constitutes a further step towards a comprehensive understanding of drug resistance in ovarian cancer.
Project description:Drug resistance poses a major challenge to ovarian cancer treatment. Understanding mechanisms of drug resistance is important for finding new therapeutic targets. In the present work, a cisplatin-resistant ovarian cancer cell line A2780-DR was established with a resistance index of 6.64. The cellular accumulation of cisplatin was significantly reduced in A2780-DR cells as compared to A2780 cells consistent with the general character of drug resistance. Quantitative proteomic analysis identified 340 differentially expressed proteins between A2780 and A2780-DR cells, which involve in diverse cellular processes, including metabolic process, cellular component biogenesis, cellular processes and stress responses. Expression levels of Ras-related proteins Rab 5C and Rab 11B in A2780-DR cells were lower than those in A2780 cells as confirmed by real-time quantitative PCR and western blotting. The short hairpin (sh)RNA-mediated knockdown of Rab 5C in A2780 cells resulted in markedly increased resistance to cisplatin whereas overexpression of Rab 5C in A2780-DR cells increases sensitivity to cisplatin, demonstrating that Rab 5C-dependent endocytosis plays an important role in cisplatin resistance. Our results also showed that expressions of glycolytic enzymes PKM, GPI, Aldolase, LDH, and PGK were down-regulated in drug resistant cells, indicating drug resistance in ovarian cancer is directly associated with a decrease in glycolysis. Furthermore, it was found that glutathione reductase were up-regulated in A2780-DR, while vimentin, HSP90, and Annexin A1 and A2 were down-regulated. Taken together, our results suggest that drug resistance in ovarian cancer cell line A2780 is caused by multifactorial traits, including the down-regulation of Rab 5C-dependent endocytosis of cisplatin, glycolytic enzymes and vimentin, and up-regulation of antioxidant proteins, suggesting Rab 5C is a potential target for treatment of drug-resistant ovarian cancer. This constitutes a further step towards a comprehensive understanding of drug resistance in ovarian cancer.
Project description:Ovarian cancer is the most lethal gynecological malignancy. Recurrence and chemoresistance are tough challenges leading to poor prognosis. HJURP is a molecular chaperone of CENP-A, which is associated with aggressive progression in multiple tumors. However, the function of HJURP in ovarian cancer has not been elucidated. In our study, we found HJURP was over-expressed in ovarian cancer and high expression of HJURP was correlated to unfavorable prognosis. HJURP knockdown could inhibit proliferation, metastasis and induce G0/G1 stagnation of ovarian cancer cells. Besides, next-generation sequencing(NGS) unveiled that WEE1 was down-regulated by silencing HJURP. Further mechanistic research revealed that HJURP regulated WEE1 through MYC, and luciferase assay indicated that MYC was a transcription factor of WEE1. Additionally, we investigated that silencing HJURP increased sensitivity of ovarian cancer cells to cisplatin via MYC/WEE1 axis, and HJURP participated in DNA repair of cisplatin-induced damage. More interestingly, silencing HJURP could enhance sensitivity of ovarian cancer cells to AZD1775 and improve the synergistic effect of cisplatin plus AZD1775 combined therapy. Collectively, our data displays that HJURP promotes tumor progression and chemoresistance of ovarian cancer, and HJURP has potential to be a novel therapeutic target in the combined treatment with cisplatin and AZD1775 in ovarian cancer.
Project description:Collagen type XI alpha 1 (COL11A1) is identified as one of the most upregulated genes in cisplatin-resistant ovarian cancer and recurrent ovarian cancer. However, the exact functions of COL11A1 in cisplatin resistance are unknown. The goal of this study is to determine molecular mechanisms by which COL11A1 confers cisplatin resistance in ovarian cancer cells. We overexpressed COL11A1 in A2780 and OVCAR3 ovarian cancer cells, which express very low endogenous levels of COL11A1. We then compared the mRNA expression levels of various genes between COL11A1-overexpressing ovarian cancer cells and control ovarian cancer cells by RNA-Seq. Our RNA-Seq data show that COL11A1 overexpression did not consistently change the expression levels of genes involved in cisplatin efflux, glutathione metabolism, and DNA repair pathways, which are known to contribute to cisplatin resistance. This result implies that COL11A1 might confer cisplatin resistance in ovarian cancer cells through other mechanisms.
Project description:Advanced ovarian cancers are initially responsive to chemotherapy with platinum drugs but develop drug resistance in most cases. We showed recently that hepatocyte growth factor (HGF) enhances death of human ovarian cancer cell lines treated with cisplatin (CDDP) and that this effect is mediated by the p38 mitogen-activated protein kinase. In this work, we integrated genome-wide expression profiling, in silico data survey, and functional assays to identify transcripts regulated in SK-OV-3 ovarian cancer cells made more responsive to CDDP by HGF. Using oligonucleotide microarrays, we found that HGF pretreatment changes the transcriptional response to CDDP. Quantitative reverse transcription-PCR not only validated all the 15 most differentially expressed genes but also confirmed that they were primarily modulated by the combined treatment with HGF and CDDP and reversed by suppressing p38 mitogen-activated protein kinase activity. Among the differentially expressed genes, we focused functional analysis on two regulatory subunits of the protein phosphatase 2A, which were down-modulated by HGF plus CDDP. Decrease of each subunit by RNA interference made ovarian cancer cells more responsive to CDDP, mimicking the effect of HGF. In conclusion, we show that HGF and CDDP modulate transcription in ovarian cancer cells and that this transcriptional response is involved in apoptosis regulation. We also provide the proof-of-concept that the identified genes might be targeted to either increase the efficacy of chemotherapeutics or revert chemotherapy resistance.
Project description:Understanding the mechanism of resistance in platinum-based regimens for the treatment of high-grade serous ovarian cancer (HGSOC) is important for identifying new therapeutic targets to improve the clinical outcome of ovarian cancer patients. Mass spectrometry-based proteomic strategy was applied to spheroidal cisplatin sensitive and resistant HGSOC generated cell lines in the absence and presence of cisplatin drug. A complete expressed HGSOC proteome and phosphoproteome was characterized in cisplatin sensitive and resistant HGSOC cell lines providing insight into the mechanism of resistance development. PCA analysis showed that phosphorylation of a few proteins provides better classification than the whole proteome of the cellular subtypes. Specifically, a distinctive phosphoproteomic signature between cisplatin sensitive and resistant cell lines in the absence of drug was observed. This same phosphoproteomic signature was observed in our cisplatin sensitive cell line in the absence and presence of drug, indicating a vital role for phosphorylation of proteins in resistance development to cisplatin. The most phosphorylated protein was sequestosome (p62/SQSTM1). Differential expressions of apoptosis by the prognostic factor ratio of Bcl-2/Bax and autophagy, known to be regulated by p62/SQSTM1, was validated in the proteome data and by western blot analysis. A significant increase in apoptosis in the presence of cisplatin was observed in only the sensitive cell line while autophagy revealed increased expression in the resistant relative to sensitive cell line. Furthermore, site specific phosphorylation on 20 modified residues of sequestosome was characterized. Elevated expression of phosphorylation of sequestosome in resistant HGSOC cell lines was validated with western blot analysis. Here, we propose phosphorylation of sequestosome to be a marker and key in cisplatin resistance development in HGOSC ovarian cancers by shuttling ubiquitinated proteins to the autophagy pathway and influencing down-regulation of apoptosis.
Project description:Chemotherapy resistance presents a major hurdle for cancer treatment. We proposed to identify the molecular changes through which breast cancer cells evolve resistance to conventional treatment, here cisplatin, so targeted therapy can be developed. Candidate approach RNAi screening was combined with cisplatin treatment in order to identify molecular pathways conferring survival advantages. The screening identified ATP7A, a copper transport ATPase responsible for the intercellular movement and sequestering of cisplatin, as a therapeutic target. Copper chelation with tetrathiomolybdate (TM) targets ATP7A. TM in combination with cisplatin sensitized drug-resistant breast cancer cells. Allograft and xenograft models in aythymic mice treated with TM/cisplatin combination therapy inhibited tumor growth and increased survival compared with monotreated mice. Examination of the molecular effects of TM on cisplatin efficacy in drug-resistant tumors revealed reduced levels of APT7A, reduced cisplatin sequestering by ATP7A and increased nuclear availability of cisplatin. Further, we showed that TM treatment combined with cisplatin reduced the half-life of ATP7A in human breast cancer cell lines. This finding offered the potential to combat drug platinum-resistant tumors and sensitize patients to conventional breast cancer treatments by identifying and targeting resistant tumors’ unique molecular adaptations.
Project description:Cisplatin-resistance is a major cause of treatment failure in human ovarian cancer. Besides lots of genes involved, emerging evidences demonstrate that miRNAs contribute to cisplatin-resistance in cancer. We measured the miRNA expression profiles of cisplatin-resistant C13K ovarian cancer cell line compared with its cisplatin-sensitive OV2008 parent cell line using miRNA microarrays.
Project description:Characterization of differential gene expression due to cisplatin resistance in human ovarian cancer spheroids by microarray analysis. In this dataset, we include the expression data obtained from cisplatin-sensitive and cisplatin-resistant human ovarian cancer spheroids. These data are used to obtain 1316 genes that are differentially expressed in response to cisplatin resistance.
Project description:A2780 is a cisplatin sensitive ovarian cancer cell line. A2780 ovarian cancer cells was treated with different doses of cisplatin in an attempt to identify biomarkers that can be used to predict chemoresponse. We used microarrays to identify genes induced by cisplatin in a time dependent manner.