Mechanism Of Programmed Cell Death Induced By Corilagin In Human Gastric Cancer Cells

As a common gastrointestinal malignant tumor,gastric cancer is originated from gastric epithelial cells.It is a serious threat to human health.In recent years,although a decreasing trend in gastric cancer incidence and lethality rates has been noted in many countries,it currently has not been effectively treated due to its extremely complex aetiology.Surgical resection is currently the main method for the treatment of gastric cancer,but it is prone to recurrence and metastasis after surgery.Consequently,finding novel effective anticancer drugs are crucial for gastric cancer therapy.Corilagin is a unique component of the tannin family.It has been discovered in many medicinal plants and is the main active monomer of Phyllanthus species.Previous studies have showed that corilagin has a wide range of biological activities such as anti-inflammatory,hepatoprotective,antiviral and antitumor.In recent years,corilagin gradually gets more and more attention by people in antitumor effect.Furthermore,some literatures have confirmed that corilagin has a significant inhibitory effect on liver cancer,ovarian cancer and glioblastoma.However,the biological effects of corilagin on gastric cancer and its mechanism are still unclear.In this study,the human gastric cancer cell lines SGC-7901 and BGC-823 are regarded as the research object to investigate the effect of corilagin on programmed death and its mechanism in human gastric cancer cells.Firstly,we detected the viabilities of gastric cancer SGC-7901 and BGC-823 cells using MTT assay and Edu staining assay.After treatment with different concentrations corilagin for 24 h,the results showed that corilagin inhibited significantly cell proliferation of both cancer cell lines in a concentration-dependent manner compared with the control group.Additionally,using the MTT assay,we examine the effect of corilagin on the growth of human gastric mucosal epithelial GES-1 cells.The results indicated that corilagin has potent antitumor activity against gastric cancer cells and less toxicity to normal cells.Next,the morphological characteristics were observed by fluorescent dye Hoechst33342 staining,and the apoptosis rate was detected with Annexin V-FITC/PI double staining assay in gastric cancer SGC-7901 and BGC-823 cells.After being exposed to corilagin for 24 h,the results suggested that corilagin can induce gastric cancer cell lines SGC-7901 and BGC-823 apoptosis in a dosedependent manner.Furthermore,the expression of apoptosis-related proteins was examined by Western blot analysis.we found that corilagin treatment decreased the protein levels of procaspase-8,-9 and-3 in a dose-dependent manner.Furthermore,corilagin increased the amount of cleaved PARP(poly ADP-ribose polymerase)in a concentration-dependent manner.The results suggested that corilagin induced caspase-dependent apoptosis in human gastric cancer cells.Then,we use acridine orange(AO)staining,MTT assay and Western blot analysis to corroborate whether corilagin triggers the occurrence of autophagy.These data indicated that corilagin induced autophagy in gastric cancer cells and inhibition of autophagy can improve the effect of corilagin on cell proliferation suppression.Therefore,it is considered that autophagy can serve as a protective role in gastric cancer cells.In addition,the results from flow cytometric analysis and MTT assay respectively revealed that corilagin significantly increased ROS generation in a dosedependent manner,and ROS may play a vital role in inhibiting growth of human gastric cancer cells caused by corilagin treatment in gastric cancer cells.Finally,we performed Real-time PCR and western blot analysis to examine whether corilagin induces necroptosis in gastric cancer cells,the results demonstrated that corilagin cannot induce necroptosis in SGC7901 and BGC823 cell lines.In summary,the data of this study indicate that corilagin can induce apoptosis,autophagy and accumulation of ROS in gastric cancer SGC7901 and BGC823 cell lines.However,as a new cell death pathway,necroptosis cannot be induced by corilagin-incubation in gastric cancer cells.Consequently,a natural production,corilagin may be a new promising drug for the treatment of human gastric cancer.