The Mechanism Of Colon Cancer Cell Apoptosis Induced By Ginsenoside 20(S)-protopanaxadiol

Colon cancer is one of the most deadly malignant diseases and the third leading cause of human death.Colon cancer develops rapidly and can easily migrate to surrounding lymph and vascular tissue,liver and so on.However,the current prognosis for colon cancer is not optismistic,and the effect of chemotherapy drugs is not obvious.Therefore,the development of small molecule drugs that can inhibit colon cancer is crucial.20(S)-Proptopanaxadiol(PPD)is a trace component produced by the metabolism of ginsenosides such as Rg3 and Rk1 in the large intestine by some microorganisms and has certain biological activity.According to reports,20(S)-PPD and its derivatives 20-GPPD and 2H-PPD can inhibit the growth of various tumor cells by inducing apoptosis,such as breast cancer,liver cancer,and glioblastoma.The aim of this thesis is to study the 20(S)-PPD-induced apoptosis of colon cancer cells through biochemical and cell biological research methods,and to reveal the molecular mechanism of its role in the application of 20(S)-PPD in cancer treatment.Theoretical basis.The following researches have mainly been conducted:1)The survival rate of human colon cancer HCT-116 and SW480 cells treated with 20(S)-PPD was determined by MTT assay and the drug activity was analyzed.2)The appropriate drug concentration and action time were selected according to the results of MTT assay under the effect of 20(S)-PPD on colon cancer HCT-116 and SW480 cells;3)Analysis of apoptosis morphology,flow cytometry(PI/Annexin V-FITC double staining),Western Blot detection of Caspase-3 substrate PARP cleavage,and in vitro determination of Caspase-3 activity 20(S)-PPD can induce apoptosis4)The specific signal pathways of apoptosis induced by 20(S)-PPD in HCT-116 and SW480 cells were further determined by detecting Caspase-8,Caspase-9 enzyme activity,mitochondrial membrane potential analysis,Western Blot and other methods.5)The transcriptional level of several important death receptors and death ligands in exogenous apoptotic signaling pathway was detected by reverse transcription-PCR and the effect of 20(S)-PPD on membrane death receptor signaling pathway was studied.In summary,20(S)-PPD inhibits colon cancer cell growth by inducing apoptosis of human colon cancer SW480 and HCT-116 cells.MTT assay results showed that 20(S)-PPD could effectively inhibit the proliferation of these two cancer cells with IC50 values of 3.3 ?g/mL and 4.1 ?g/mL,respectively.We demonstrated that 20(S)-PPD can be mediated through mitochondria-mediated endogenous apoptotic pathways,as well as through exogenous types,using Caspase in vitro viability assays,mitochondrial membrane potential assays,flow cytometry,and Western Blot.Apoptotic pathway to induce death of HCT-116 cells.However,20(S)-PPD can only induce SW480 cell death through the mitochondrial pathway.