An Experimental Study On CDC2 Silencing Increases The Sensitivity Of Gastric Cancer SGC-7901 Cells To Oxaliplatin

Gastric cancer is one of the most common tumor in the digestive system,which has high morbidity and mortality in our country,and it remains the second leading cause of cancer death worldwide.Early gastric cancer can becured based on surgical resection,but advanced gastric cancer is diffcult to be cured,and patients with advanced gastric cancer always have a short survival time.Due to the hidden symptoms of gastric cancer,it is not easy to be diagnosed in the early stage,most of the diagnosis of gastric cancer is in the late stage.Although there are many molecular targeted drugs and immunotherapy that providing new treatment strategies for advanced gastric cancer,systemic chemotherapy is still the primary treatment for advanced gastric cancer.The chemotherapy regimen based on oxaliplatin plays an important role in the treatment of gastric cancer,but many patients are born or acquired resistance to platinum drugs.Because of the resistance,the curative effect of platinum-based drugs has been greatly reduced and its clinical application is limited.So it is necessary to search for the genes related to the sensitivity of platinum drugs in gastric cancer.These findingsmay provide some theoretical basis for predicting the curative effect of platinum-based chemotherapy,the formulation of individualized treatment,and new therapeutic targets for patients with gastric cancer.It even improved the effect of platinum-like drugs on the chemotherapy of gastric cancer and even reversed the platinum resistance.Finally,these achievement will benefit the patient patients with gastric cancer.Cell division cycle gene?CDC?is a kind of gene closely related to cell cycle regulation,and they control the cell cycle and the transformation of each phase.As the most important of this type of gene,CDC2is the only CDC gene that acts on two control points?G1/S and G2/M?in the cell cycle.The abnormal expression of CDC2 is found in many malignant tumors.CDC2 may be associated with the formation,proliferation and drug resistance of malignant cells.In this paper,the difference expression of CDC2 in gastric cancer cell lines and changes in the sensitivity of gastric cancer cell lines to oxaliplatin were discussed,thus revealing the role of CDC2in the treatment of gastric cancer in oxaliplatin.Objective:To explore the effect of RNA interference?RNAi?-silenced CDC2gene onchemosensitivity to oxaliplatin of SGC-7901 cell lines.Methods:Three specific CDC2 interference fragment CDC2 siRNA1,CDC2siRNA2 and CDC2 siRNA3 were designed and constructed to CDC2 DNA.,and transfected into gastric cancer SGC-7901 cells,blank control group and negative control group were set up at the same time;qPCR and Western blotting were used to detect the expression of CDC2 mRNA and protein in the SGC-7901 cells,and the interfering fragment with best transfection effect was se-lected.CCK-8 assay were used to determine the proliferation ability of SGC-7901 cellswhen down-regulated the expression of CDC2,and recorded the proliferation inhibition rate of SGC-7901 cells which were treated by different concentrations of oxaliplatin and calculate the semi-inhibitory concentration(IC₅₀).Results:With the transfection of specific CDC2 interference fragment,compared with blank control group,the expression level of CDC2 mRNA for three groups of SGC-7901 cells?CDC2 siRNA1,CDC2 siRNA2 and CDC2 siRNA3?were reduced by 35%,53%and85%,respectively.The relative protein expression of SGC-7901 cells in CDC2 siRNA3 group was 0.227±0.015,lower than 0.848±0.025and 0.842±0.016 of blank control group and negative control group?P<0.05?.SiRNA3 interfering fragment was used in the following experiments.The expression level of CDC2 was deregulatedobviously when CDC2 siRNA3interference fragment was transfected into gastric cancer cells,it can significantly inhibit the growth of gastric cancer cell activity and reduce its proliferation,and reached a plateau in 72-96h,the cell proliferation activity of experimental group was significantly lower than the blank control group?P<0.05?and the negative control group cells.With different concentrations of oxaliplatin treated in each group for 24 h,the proliferation inhibited rate in CDC2 siRNA3 group was higher than those of the other two group?P<0.05?.The IC₅₀ of oxaliplatin to CDC2 siRNA3 group,blank control group and negative control group were 3.91?6.58 and 6.68?mol/L.Conclusion:Down-regulating the expression of CDC2 can significantly strengthen the sensitivity of SGC-7901 cells to oxaliplatin,and maybe provide an optional target to increase the chemosensitivity of gastric cancer to oxaliplatin.