Effect Of Polβ SiRNA On Proliferation And Sensitivity To Cisplatin On Human Ovarian Carcinoma Cell Line

Background and ObjectiveDNA polymeraseβ(polβ) is a member of family X, Which is structurally different from the A, B, and Y families. The primary function of which is the base excision repair (Base excision repair, BER) process, playing an important part in filling the single nucleotide gap. It is called as "housekeeping enzyme" in biological evolution because of its error-prone features.DNA polβwas mainly involved in DNA repair after damage, DNA synthesis cross the damage.Under normal circumstance, in our body polymeraseβexpresses in a constant low level. There were many researches explained that polβhad a high level of expression in gene and protein in prostatic cancer, liver cancer, lung cancer, gastric cancer, esophageal cancer, pancreatic cancer, colorectal, nasopharyngeal cancer, breast cancer, and other tumors. The level polβexpressed was accordance with the development of ovarian cancer. DNA polymeraseβin ovarian cancer was significantly higher than in normal ovarian tissue, from normal tissue to the cancer process, the expression of polβincreased gradually.RNA interference (RNA interference, RNAi) technology is the role of the homologous sequence of mRNA, about 21 to 23 nucleotide, double-stranded RNA-mediated sequence-specific, post-transcriptional gene silencing.Until now, there was no report on ovarian cancer using RNAi. So, this study transfected siRNA-polβinto human ovarian cancer HO-8910 the first time, then observeing the proliferation activity and sensitivity to cisplatin of HO-8910.RNAi technology can significantly inhibit the expression of polβin ovarian cancer, polβfor further research on the biological behavior of cells and their sensitivity to chemotherapeutic drugs in the mechanism of action provides an effective method, and hopefully be of ovarian Cancer gene therapy is an important tool for effective intervention and treatment of tumors to develop a new field.Therefore, the subject took use of RNAi to knock down the expression of polβ, observing tumor cell apoptosis and sensitivity changes to cisplatin.MethodsIn order to investigate the proliferation and sensitivity to cisplatin of siRNA of polβon human carcinoma cell (HO-8910).The plasmid expressing siRNA against polβwere constructed and transected into HO-8910 cells; The transfection efficiency was observed through the fluorescence microscope; polβexpression was detected by Fluorogenic Quantitative PCR; MTT and Trypan blue dyeing were used to determine the proliferation and sensitivity to cisplatin respectively.Results1 Ater 48 hours transfection, A large number of green fluorescent particles were observed in the cell transfected pRNAT-U6.1-sipolβand pRNAT-U6.1 under fluorescence inverted microscope.2 The polβmRNA expression in cells transfected pRNAT-U6.1-sipolβwas lower than which transfected with pRNAT-U6.1 and the control cells HO-8910 without transfection (P<0.01). There was no difference between the pRNAT-U6.1 group and the control cells HO-8910 without transfection (P> 0.05).3 After 48 hours transfection, the results showed that cell proliferation rate of transfected with siRNA-polβwere much slower than the control cells and cells transfect with empty vector (P<0.05). There was no difference between the pRNAT-U6.1 group and the control cells HO-8910 without transfection (P>0.05). This explained that plasmid pRNAT-U6.1-sipollβinhibited the growth of ovarian cancer cells after transfection.4 When cisplatin concentration was within 2.5μg/ml～40μg/ml, the number of cells transfected siRNA-polβwas significantly less than the normal group and the empty vector control group (P<0.01), with the concentration of drug increased, the difference became more and more obvious, and showed concentration-dependent.Conclusions1. The expression of polβmRNA was significantly depressed in the group transfected with pRNAT-U6.1-sipolβthan normal group and the empty vector control group in ovarian carcinoma cells.2. The ability of growth and proliferation were significantly inhabited in the group transfected with pRNAT-U6.1-sipolβthan normal group and the empty vector control group in ovarian carcinoma cells.3. After the polβwas effectively silenced, the sensitivity to cDDP of cell was inhanced.