Effect Of Low-dose Radiation On Reversing The Cisplatin Resistance Of Ovarian Carcinoma Via Bad And Bax Pathway

Objective:Human epithelial ovarian carcinoma is one of the killers that seriously threatens women’s health.At the current level of medical care,the treatment of human epithelial ovarian carcinoma is relatively single.Usually,the first choice of clinical treatment is to use surgical tumor reduction combined with surgery,and then use platinum-based chemotherapy.Despite ovarian carcinoma cells is sensitive to chemotherapy,but ovarian carcinoma can easily develop resistance to chemotherapeutic drugs after multiple chemotherapy,which can also lead to tumor recurrence in most patients after receiving first-line treatment.In order to find a new breakthrough in the treatment of epithelial ovarian carcinoma,cisplatin resistant ovarian carcinoma cells（SKOV3/DDP）are used as an experimental model to explore whether low dose radiation can reverse SKOV3/DDP resistance through Bad and Bax pathway.The purpose of these studies is to provide new ideas for the treatment of drug-resistant ovarian carcinoma.Methods:In the experiment,SKOV3/DDP（cisplatin-resistant ovarian carcinoma cells）were cultured in batch in cell culture flask.And when the cell density was good,the cultured cells were randomly divided into three groups.Among them,the three groups were as follows:control group,low-dose radiation group,conventional dose group.In the course of the experiment,the control group was not treated with radiation;the low-dose radiation group was irradiated every 6 hours at a dose of 0.5 Gy,and the low-dose radiation group was irradiated4 times;and the conventional dose group was irradiated only once,and the dose of irradiation was 2Gy.CCK-8 assay was performed to measure the toxicity of cisplatin on SKOV3/DDP cells,and the IC₅₀ value of cisplatin in each group was calculated.Flow cytometry was used to quantify the apoptosis rate of SKOV3/DDP.In addition,Western blotting was used to measure the protein expression of Bad,P-Bad and Bax in SKOV3/DDP cells.Finally,RT-PCR technique was used to measure the mRNA expression of Bad and Bax in SKOV3/DDP cells.Results:CCK-8 assay showed,the proliferation inhibition rate in low-dose radiation group was significantly higher than that in the control group and conventional dose group（P<0.05）.The cisplatin IC₅₀ of the low-dose radiation group was significantly lower than the other two groups（P<0.05）.The flow cytometry showed,the apoptosis rate of SKOV3/DDP cells was significantly higher in the low-dose radiation group than that in the control group and conventional dose group（P<0.05）.The results of western blotting showed that the protein expression of P-Bad in the low-dose radiation group was significantly lower than that in the control group and conventional dose group（P<0.05）.The protein expression of Bax was significantly higher in the low-dose radiation group than other groups（P<0.05）.But there was no statistical significance in the protein expression of Bad among the three groups（P>0.05）.Compared with the control group and the conventional dose group,the relative mRNA expression of Bax in the low-dose radiation group was significantly higher than that in the control group and the conventional dose group by RT-PCR（P<0.05）.But there was no statistical significance in the relative expression of Bad among the three groups by RT-PCR（P>0.05）.Conclusion:In the known drug resistance mechanism of ovarian carcinoma in the current clinical practice,PI3K/AKT signaling pathway occupies a very important position,and Bad and Bax downstream of the pathway also play an important role in tumor cell apoptosis.It was found that low-dose radiation could increase the sensitivity of SKOV3/DDP cells to chemotherapeutic drugs（cisplatin）.This effect may be achieved by regulating the expression of Bad and Bax to enhance the apoptosis of tumor cells.In addition,this experiment may provide new vitality into the study of cisplatin-resistant ovarian carcinoma r treatment.