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Dai Z.,Peking Union Medical College | Yin J.,Peking Union Medical College | He H.,Peking Union Medical College | Li W.,Beijing Proteome Research Center | And 5 more authors.
Proteomics | Year: 2010

Resistance to platinum-based chemotherapy is the major obstacle to successful treatment of ovarian cancer. It is evident that mitochondrial defects and the dysfunctions of oxidative phosphorylation and energy production in ovarian cancer cells were directly related to their resistance to platinum drugs. Using 2-D DIGE, we compared mitochondrial proteins from two platinum-sensitive human ovarian cancer cell lines (SKOV3 and A2780) with that of four platinum-resistant sublines (SKOV3/CDDP, SKOV3/CBP, A2780/CDDP, and A2780/CBP). Among the 236 differentially expressed spots, five mitochondrial proteins (ATP-α, PRDX3, PHB, ETF, and ALDH) that participate in the electron transport respiratory chain were identified through mass spectrometry. All of them are downregulated in one or two of the platinum-resistant cell lines. Three proteins (ATP-α, PRDX3, and PHB) were validated by using western blot and immunohistochemistry. There is a significant decrease of PHB in tumor tissues from ovarian cancer patients who were resistant to platinum-based chemotherapies. This is the first direct mitochondrial proteomic comparison between platinum-sensitive and resistant ovarian cancer cells. These studies demonstrated that 2-D DIGE-based proteomic analysis could be a powerful tool to investigate limited mitochondrial proteins, and the association of PHB expression with platinum resistance indicates that mitochondria defects may contribute to platinum resistance in ovarian cancer cells. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chen X.,Nanjing University | Chen X.,Jiangsu Institute of Cancer Research | Wang J.,Nanjing University | Guo W.,Nanjing University | And 5 more authors.
Breast Cancer Research and Treatment | Year: 2011

8-Hydroxy-2'-deoxyguanine (8-OHdG) is produced by the oxidative stress-induced damage in DNA, which could pair with adenine (A) during DNA replication, leading to G-T transversion mutations. Glycosylase hOGG1 can recognize and excise oxidized guanines from duplex DNA. This work aims to investigate the relationship between the functional variations in 5-untranslated region (5'-UTR) of hOGG1 gene and the risk of breast cancer. Genotypes were analyzed in 518 sporadic breast cancer patients and 777 health controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by logistic regression. Risk-stratified subgroup analysis was performed to reveal the associations between the detected variations and the risk of characteristic breast cancer. In addition, immunohistochemistry was carried out to assess the functional effect of these variations on hOGG1gene expression. Five variations in 5'-UTR of hOGG1 gene are found in this study. Three of them, c.-18G>T, c.-23A>G, and c.-53G>C, are known single nucleotide polymorphisms, the other two, c.-45G>A and c.-63G>C, are rare variations. The frequency of c.-18G/T and c.-53G/C was significantly higher in breast cancer patients than those in healthy controls (P = 0.03, OR 2.01, 95% CI 1.04-3.90; and P = 0.01, OR 2.43, 95% CI 1.17-5.04, respectively). Both variations were especially prevalent in premenopausal status, and in the triple (estrogen receptor, progesterone receptor, and human epidermal growth factor Receptor 2) negative subgroups, respectively. Moreover, the variation of c.-18G>T could cause a reduced expression of hOGG1 gene. © 2010 Springer Science+Business Media, LLC.

Zhu M.,Nanjing University | Zhu M.,Jiangsu Institute of Cancer Research | Chen H.-M.,Nanjing University | Wang Y.-P.,Nanjing University
Oncology Letters | Year: 2013

The MLH1 and MSH2 genes in DNA mismatch repair are important in the pathogenesis of gastrointestinal cancer. Recent studies of normal and alternative splicing suggest that the deleterious effects of missense mutations may in fact be splicing-related when they are located in exonic splicing enhancers (ESEs) or exonic splicing silencers (ESSs). In this study, we used ESE-finder and FAS-ESS software to analyze the potential ESE/ESS motifs of the 114 missense mutations detected in the two genes in East Asian gastrointestinal cancer patients. In addition, we used the SIFT tool to functionally analyze these mutations. The amount of the ESE losses (68) was 51.1% higher than the ESE gains (45) of all the mutations. However, the amount of the ESS gains (27) was 107.7% higher than the ESS losses (13). In total, 56 (49.1%) mutations possessed a potential exonic splicing regulator (ESR) error. Eighty-one mutations (71.1%) were predicted to be deleterious with a lower tolerance index as detected by the Sorting Intolerant from Tolerant (SIFT) tool. Among these, 38 (33.3%) mutations were predicted to be functionally deleterious and possess one potential ESR error, while 18 (15.8%) mutations were predicted to be functionally deleterious and exhibit two potential ESR errors. These may be more likely to affect exon splicing. Our results indicated that there is a strong correlation between missense mutations in MLH1 and MSH2 genes detected in East Asian gastrointestinal cancer patients and ESR motifs. In order to correctly understand the molecular nature of mutations, splicing patterns should be compared between wild-type and mutant samples.

Lu Y.,Nanjing University | Lu Y.,Jiangsu University | Liu Y.,Jiangsu Institute of Cancer Research | Jiang J.,Peoples Hospital of Yixing City | And 5 more authors.
Oncology Reports | Year: 2014

A hallmark of small cell lung cancer (SCLC) is frequent relapse characterized by newfound resistance to formerly efficacious chemotherapies. The prognosis for SCLC patients is particularly unfavorable. Aurora kinase A (AURKA), a member of the serine/threonine kinase family, is overexpressed across many types of human tumors. Recent studies have identified AURKA as an important factor in tumorigenesis, but little is known regarding its specific roles in SCLC. The aim of the present study was to establish the roles of AURKA in the molecular pathogenesis of human SCLC. In the present study, we constructed a lentiviral vector to express siRNA against AURKA (LV-AURKA siRNA). As we expected, the viral construct effectively suppressed the expression of the AURKA gene and protein in H446 and H1688 cell lines. Additionally, RNA interference of AURKA inhibited the colony formation and subsequent growth of H446 and H1688 cell lines by increasing the incidence of cell cycle arrest in the G2/M phase. Furthermore, suppression of AURKA by LV-AURKA siRNA also increased apoptosis of SCLC cells. A potential mechanism for the increase of apoptosis is the downregulation of Bcl-2 and upregulation of Bax. AURKA gene suppression may provide a novel, effective therapy for SCLC patients by inhibiting cell division and increasing the rate of apoptosis of SCLC cells.

Xu X.,Jiangsu Institute of Cancer Research | Wang Y.,Nanjing Medical University | Guo W.,Nanjing University | Zhou Y.,Jiangsu Institute of Cancer Research | And 4 more authors.
Journal of Ovarian Research | Year: 2013

Background: Oxidative damage and DNA repair dysfunction are associated with carcinogenesis. 8-OHdG is one of the major oxidative DNA adducts. Present work aims to investigate whether the expression of 8-OHdG and its key repair gene hOGG1 play distinctive role in two types of serous ovarian cancer. Materials and methods. 8-OHdG level in DNA from tumor and matched tumor-adjacent normal tissue in 48 high-grade papillary serous carcinomas (HG-SOC), 24 low-grade papillary serous carcinomas (LG-SOC), 20 serous cystadenomas, and 16 non-tumor control ovaries was tested. The Cox proportional hazards model and the log-rank test were used to assess the associations between the 8-OHdG level in two types of serous cancer and patients' survival. Real-time polymerase chain reaction and protein immunoblot were employed to detect hOGG1 mRNA and protein levels in tumor and adjacent normal tissues. Immunohistochemistry was used to determine the expression of hOGG1 and p53. Results: There was no difference of average 8-OHdG/10§ssup§6§esup§dG DNA level either between HG-SOC (27.8 ± 8.9), LG-SOC (25.2 ± 7.4) and benign serous cystadenoma (26.5 ± 7.7, p = 0.35); or between the tumor-adjacent normal tissue of HG-SOC (18.8 ± 5.2), LG-SOC (21.4 ± 6.5), benign serous cystadenoma (20.5 ± 9.1) and non-tumor ovary (21.6 ± 4.9, p = 0.62). The 8-OHdG/10§ssup§6§esup§dG level was significantly higher in tumor comparing to that in matched normal tissue adjacent to carcinoma in HG-SOC (1.52 ± 0.52, p = 0.02), but not in LG-SOC or benign serous cystadenoma. Increased level of 8-OHdG in tumor DNA was an independent factor of overall survival in serous ovarian carcinoma upon multivariate analysis (p < 0.01). Increased level of 8-OHdG in tumor DNA indicates poorer overall and progression-free survival durations than counterparts (47.3 vs 105.7 months and 13.5 vs 45.3 months, respectively). Protein levels of hOGG1 were remarkably decreased in HG-SOC (p < 0.01), but not in LG-SOC and serous cystadenoma compared with the tissue adjacent to carcinoma. A positive result on p53 immunostaining was associated with lower hOGG1 expression in HG-SOC (p = 0.04). Conclusion: Increased 8-OHdG level and decreased expression of hOGG1 in tumor were found in HG-SOC but not LG-SOC. Increased 8-OHdG level in tumor DNA was significantly associated with poorer overall survival and progression-free survival in serous ovarian carcinoma. © 2013 Xu et al.; licensee BioMed Central Ltd.

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