Securinine Induces S-phase Arrest And Apoptosis Of Human Colon Cancer SW620 Cells Through MAPKs Signaling Pathway

Background:Colorectal cancer is the third most common malignancy worldwide and the second most common cause of cancer death.With the development of modern surgical techniques and the improvement of chemotherapy and radiotherapy,there are many patients with recurrence and metastasis of colon cancer after surgery.Some natural anticancer active ingredients can be used in the comprehensive treatment of colon cancer,which can improve the clinical efficacy.Securinine（Sec）,also known as Secinine,is the main alkaloid extracted from the leaves or roots of euphorbiaceae.Sec can stimulate spinal cord and brain stem central nervous system,improve hematopoietic microenvironment,promote the proliferation of granulocytes,erythrocytes,megakaryocytes and other pharmacological and clinical application value,but there is no report on gastrointestinal tumors.Therefore,the effect of Sec on the proliferation of colon cancer SW620 cells was investigated from the perspective of cell cycle and apoptosis.Objective:To investigate the effect of Sec on cell cycle and apoptosis of human colon cancer SW620 and its mechanism.Methods:The SW620 cells were divided into Control Group,20μmol/L Sec Group,40μmol/L Sec Group,80μmol/L Sec Group,40μmol/L Oxaliplatin（Oxa）Group.1.The effect of Sec on proliferation of SW620 cells was detected by CCK8method.2.The effect of Sec on SW620 cell cycle was detected by flow cytometry and western blotting.3.The effect of Sec on apoptosis of SW620 cells was detected by TUNEL and flow cytometry,DCFH-DA was used to detect ROS level,the mitochondrial membrane potential was detected by JC-1,the protein expression of p53,Cleaved Caspase-9,Cleaved Caspase-3,Cleaved PARP,Bcl-2,Bax and Cytochrome C were detected by western blotting.4.The protein expression levels of JNK,p-JNK,p38,p-p38,ERK and p-ERK were detected by western blotting.Results:1.Compared with the Control group,the survival rate of SW620 cells was significantly decreased when Sec concentration was greater than 20μmol/L（P<0.0001）.2.Compared with the Control Group,the percentage of S-phase cells in SW620 cells in each dose group of Sec was significantly increased（P<0.0001）,the percentage of cells in G₀/G₁phase and G₂/M phase decreased significantly（P<0.0001）,The expression levels of CDK2 and Cyclin A1 were significantly increased（P<0.0001）.3.Compared with the Control Group,the apoptosis rate of SW620 cells in each dose group of Sec was significantly increased（P<0.0001）,the level of cellular ROS was significantly increased（P<0.0001）,the mitochondrial membrane potential was significantly decreased（P<0.0001）,the protein expression levels of p53,Cleaved Caspase-9,Cleaved Caspase-3,Cleaved PARP,Bax,and Cytochrome C were significantly increased（P<0.05,P<0.01,P<0.001 and P<0.0001）,and the protein expression level of Bcl-2 was significantly decreased（P<0.0001）.4.Compared with the Control Group,the protein expression levels of p-JNK、p-p38、p-ERK in SW620 cells in each dose group of Sec were significantly increased（P<0.0001）.Conclusions:Sec can inhibit the proliferation of SW620 cells,arrest the cell cycle in S phase,and induce the apoptotic mitochondrial pathway,the mechanism of which may be related to the regulation of MAPKs signaling pathway.