Metformin in combination with cisplatin inhibits cell viability and induces apoptosis of human ovarian cancer cells by inactivating ERK 1/2.

Metformin protects against insulin resistance by restoring insulin sensitivity and may also possess anticancer activity. The aim of the present study was to investigate the effects of metformin alone or combined with cisplatin (DDP) on the cell viability and apoptosis of HO-8910 human ovarian cancer cells, and to investigate metformin as a potential novel therapeutic for treating ovarian cancer. The viability of HO-8910 cells was assessed using a cell proliferation and cytotoxicity assay following treatment with different concentrations of metformin (0.01, 0.5, 1, 5 and 10 mM) and/or 5 µM of DDP. Flow cytometry was performed to examine cell apoptosis, and western blotting was used to measure the expression of extracellular signal-related kinase 1/2 (ERK1/2) phosphorylated (p)-ERK1/2, vascular endothelial growth factor (VEGF), VEGF receptor 2 (VEGFR2), B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X (Bax) and caspase-3. The resultsof the present study revealed that metformin reduced the viability of HO-8910 cells in a time- and concentration-dependent manner and induced cell apoptosis in a concentration-dependent manner. Metformin combined with DDP evidently inhibited cell viability and induced apoptosis. In addition, ERK1/2 and genes associated with apoptosis regulation, such as VEGF, VEGFR2, Bcl-2, Bax and caspase-3, exhibited differential expression in the HO-8910 cells. The present study demonstrated that expression of p-ERK1/2, VEGF, VEGFR2 and Bcl-2 was downregulated by treatment with increasing concentrations of metformin, whereas expression of Bax and caspase-3 was evidently upregulated. Taken together, these data demonstrate that metformin in combination with DDP reduces cell viability and induces apoptosis of human ovarian cancer cells.

Desmocollin 3 mediates follicle stimulating hormone-induced ovarian epithelial cancer cell proliferation by activating the EGFR/Akt signaling pathway.

Follicle-stimulating hormone (FSH) is associated with the pathogenesis of ovarian cancer. We sought to explore whether desmocollin 3 (Dsc3) mediates FSH-induced ovarian epithelial cancer cell proliferation and whether the EGFR/Akt signaling pathway may be involved in this process. Dsc3 positivity in ovarian tissue specimens from 72 patients was assessed by immunohistochemistry. The positive expression rates of Dsc3 were similar in ovarian cancer tissues (24/31:77.4%) and borderline ovarian tumor tissues (18/22:81.8%) (P>0.05), but were significantly higher in these cancerous tissues than in benign ovarian cyst tissues (3/19:15.8%) (P<0.05). Consistently, the expression of Dsc3 in four out of five ovarian cancer cells (HO8910, Skov3ip, Skov and Hey cells, but not ES-2 and in borderline ovarian MCV152 tumor cells was higher than in the immortalized ovarian epithelial cell line, Moody. FSH up-regulated the expression of Dsc3 and EGFR in a dose- and time-dependent manner. Furthermore, a converse relationship between the expression of Dsc3, EFGR and PI3K/Akt signaling was elucidated using RNA interference and PI3K/Akt inhibitor in the absence and presence of FSH. A role for these proteins in FSH-induced cell proliferation was verified, highlighting their interdependence in mediating ovarian cancer cell function. These results suggest that Dsc3 can mediate FSH-induced ovarian cancer cell proliferation by activating the EGFR/Akt signaling pathway.

Long noncoding RNA-EBIC promotes tumor cell invasion by binding to EZH2 and repressing E-cadherin in cervical cancer.

In recent years, long noncoding RNAs (lncRNAs) have been demonstrated to play key roles in tumorgenesis. However, the contributions of lncRNAs to cervical cancer (CC) remain largely unknown. In this study, differentially expressed lncRNAs and mRNAs in cervical cancer and paired peritumoral tissues were detected by transcriptome microarray analysis. We found 708 probe sets of lncRNAs increased and 836 probe sets decreased in CC tissues, while 1288 mRNA differential probe sets increased and 901 mRNA probe sets decreased. The results were validated by quantitative real-time polymerase chain reaction (qPCR). Then, we found a specific differentially expressed lncRNA can physically bind to enhancer of zeste homolog2 (EZH2) by using RNA immunoprecipitation. We termed it as EZH2-binding lncRNA in cervical cancer [lncRNA-EBIC]. Wound healing assays and Matrigel invasion assays were used to determine the function of this lncRNA by silencing it. We observed that the migration and invasion of cervical cancer cells in vitro were inhibited upon suppression of lncRNA-EBIC by siRNA. We also found that the association between lncRNA-EBIC and EZH2 was required for the repression of E-cadherin, which was a key molecular in the metastasis of cervical cancer. Conclusion: These results demonstrated that lncRNA-EBIC was an oncogenic lncRNA, which could promote tumor cell invasion in CC by binding to EZH2 and inhibiting E-cadherin expression.

[Study on mRNA expression of the human novel gene NM23-H1B in ovarian tumor].

OBJECTIVE: To study the expression of the human novel gene NM23-H1B in ovarian cancer. METHODS: Forty-eight samples from patients with ovarian tumor at different clinical stages and 8 from normal ovaries were examined for NM23-H1B mRNA expression by using RT-PCR, northern blot and in situ hybridization. RESULTS: All samples expressed NM23-H1B mRNA through RT-PCR, while the level of expression in ovarian tumor was higher than that of normal ovary. The level of expression in early stage (stage I and II) cancer was higher than in advanced (stage III and IV) cancer. The results of northern blot showed that NM23-H1B was over expressed in ovarian cancer while low expressed in normal ovary or low malignant potential (LMP) ovarian cancer. In early stage carcinoma, the expression level was related with the differentiation of tumor cell. Well-differentiated cancer expressed NM23-H1B mRNA at comparatively higher level. The result of in situ hybridization showed that positive expression rate of NM23-H1B mRNA in ovarian cancer (100%, 40/40) was significantly higher than that in normal ovary (0/8) or LMP ovarian cancer (2/8). CONCLUSION: The novel gene NM23-H1B is related to ovarian cancer.

[In vitro experimental study of gene therapy for ovarian cancer with thymidine kinase gene of herpes simplex virus mediated by a non-viral GE7 delivery system].

OBJECTIVE: To investigate gene transfer efficiency of a novel target non-viral vector GE7 and effects of herpes simplex virus thymidine kinase (HSV(1)-tk)/ganciclovir (GCV) mediated by it in vitro. METHODS: The epidermal growth factor receptor (EGF-R) target gene delivery system GE7 was constructed. Human ovarian cancer cell line CAOV3 was transfected in vitro with beta-galactosidase (beta-gal) as reporter gene and HSV(1)-tk gene as therapeutic gene using this gene delivery system. By means of the assay of X-gal staining, Northern blotting, cell growth-inhibiting curve and so on, the transferring efficiency of exogenous genes and killing effects are observed. RESULTS: It showed that gene transfer efficiency is over 80%. When 10 mg/L GCV was put into ovarian cells transfected with HSV(1)-tk gene, 95% of cells were killed, and the apoptosis ratio reached up to 30. CONCLUSIONS: The GE7 gene delivery system is an effective and safe delivery system. GE7/HSV(1)-tk/GCV therapeutic gene system is appraising for ovarian cancer.