Effects Of RB1 Gene On The Biological Behavior And Drug Sensitivity Of Prostate Cancer LNCaP Cell Line

Background: RB1 gene is one of the earliest tumor-suppressor gene and has been proved to be associated with various of tumors.Studies have suggested that the inactivation of RB1 gene can promote the occurrence,development and metastasis of prostate cancer.A retrospective clinical study in our group also showed that the level of p RB protein expressed by RB1 gene is correlated with the time to Castration-Resistant Prostate Cancer(TTCRPC).However,there is no research on the effect of RB1 gene expression level on the biological behavior of prostate cancer cell lines and the changes of cell function under the intervention of different endocrine drugs.Objective: To investigate the correlation between RB1 gene expression product p RB protein and the overall survival of endocrine therapy-na?ve advanced prostate cancer patients.Furthermore,basic study would be conducted to explore the effect of RB1 gene on biological behaviors of prostate cancer cell lines such as proliferation(survival rate),migration(scratch healing rate),and apoptosis.At the same time,the proliferation,migration and apoptosis of prostate cancer cell lines with different RB1 gene expression status under the intervention of abiraterone and bicalutamide would be conducted to explore whether RB1 gene status can be used as a predictor of prognosis and efficacy of endocrine therapy.Methods:1.The fifty patients who were diagnosed with high/low p RB expression by immunohistochemistry at The Second Hospital of Dalian Medical University from Jan.2005 to Sep.2016 were selected as hormone-sensitive,but eventually progressed to CRPC after endocrine therapy.These patients were follow-up to get the overall-survival(OS),follow-up until Nov.2019 or the patient dead and the correlation between p RB protein level and OS was determined by statistical analysis.2.RB1 m RNA and protein expression levels of prostate cancer LNCa P,PC-3,DU-145 cells and immortalized prostatic epithelial RWPE-1 cells were detected by Real time quantity polymerase chain reaction(RT-PCR)and western blot.Three siRNA(siRNA-1,2,3)were specifically constructed based on the RB1 gene,transfection of prostate cancer cell lines to knock down RB1 gene to get the RB1 low expression prostate cancer cell lines;cell proliferation experiment,scratch test,and flow cytometry were used to analyze the proliferation,migration and apoptosis of prostate cancer cell lines after RB1 gene knockdown.Meanwhile,detection the sensitivity of prostate cancer cell lines after knockdown of RB1 against endocrine drugs(abiraterone,bicalutamide).Result:1.Statistical analysis of 50 patients showed that the median OS in the group with low p RB expression was significantly longer than that in the group with high p RB expression(51.0 months VS 19.0 months),and the difference was statistically significant(P< 0.05).2.After transfection knocked down RB1 expression by siRNA,compared with si-NC group,si-RB group had increased cell proliferation and migration ability,decreased apoptosis(P<0.05).3.Compared with the si-NC group,the si-RB group had increased cell proliferation ability,decreased apoptosis after different drug interventions,and the difference was statistically significant(P< 0.05).Compared with the no drug group,si-NC and si-RB groups all showed the decreased cell proliferation and migration ability,increased apoptosis after drugs intervention,the difference was also statistically significant(P<0.05);But there was no difference between the si-NC group and the si-RB group in cell survival rate,migration ability,and apoptotic rate between the different drug intervention groups(P> 0.05).Conclusion:1.Patients with low p RB expression group had a significantly longer median OS expression group,and p RB may be a prognostic factor for OS in advanced prostate cancer.2.The LNCa P cell line that knocked down the RB1 gene via siRNA increased the proliferation,migration ability,and decreased apoptosis;it suggested that the expression status of the RB1 gene could affect the function of the LNCa P cell line.3.Down-regulated the expression of RB1 gene,leading to the decreased of the ability that ABI and BIC to inhibit the hormone-sensitive prostate cancer LNCa P cell line,indicating that the low RB1 expression cell line has been reduced sensitivity to drugs,suggesting that the RB1 gene expression status may become prostate cancer endocrine predictors of drug efficacy.