Isoimperatorin Inhibits Proliferation And Induces Apoptosis In Gastric Cancer Cells Through PI3K Pathway

In this study,we focus the role of isoimperatorin on the stomach tumor cells,revealing the mechanism of inhibitory effect of this compound.This lay the foundation for further studyIsoimperatorin,belonging to 6,7-furan coumarin(molecular formula,C16H1404),is widely distributed in plant kingdom.Coumarin compounds have advanced application value and many biological activities.The inhibitory effect of Isoimperatorin on human gastric cancer BGC823 cells was determined by MTT method.And the cell toxicity is in linear with its concentration.The method of Annexin-V joint PI dye FITC double staining with flow cytometry instrument was applied to reveal the isoimperatorin could effectively induce apoptosis of human gastric cancer cells,whose effect is in linear with the concentration.To study molecule changes of Akt signaling pathways,western blotting was conducted to detect proteins of the Bcl-2 family members and caspase signaling.The protein level of Bax increased significantly,while the Bcl-2 protein level obviously declined.And the caspase3 and caspase9 protein levels of apoptosis signaling pathways significantly increased.This could suggest isoimperatorin induce BGC823 cell apoptosis through caspase.Nude mouse model experiment showed that isoimperatorin could inhibit BGC823 cell tumor in the body.So we could infer PI3K-AKT signaling passway play a role in the mechanism by which isoimperatorin induce cell apoptosis.Phosphoinositide-3 kinase-protein kinase B-mammalian target of rapamycin(mTOR)signaling pathway is a classical anti-apoptosis and pro-survival signal transduction pathway,it could adjust many normal cellular activities such as proliferation,survival and migration.Studies have shown that the pathway was excessive activated in gastric cancer[4].A study of 45 cases of gastric carcinoma found that the rate of p-Akt expression was up to 82.2%and the expression was related to the growth and metastasis of tumor cells.In addition,targeted to the PI3K/Akt patheay in gastric cancer treatment has also achieved some results.Studies have shown that by inhibiting PI3K/Akt signaling pathway metastasis and invasion of gastric cancer cells can be reduced and apoptosis can be induced.Dihydroartemisinin and other traditional Chinese medicine extracts could inhibit PI3K/Akt pathway,then inhibit the proliferation and induce apoptosis of gastric cancer cells,which reminds us that PI3K/Akt pathway may be used as a potential therapeutic target for gastric cancer and the mechanism need further study.In the previous study,we found isoimperatorin could inhibit the growth and proliferation of human gastric cancer cell line BGC823.Typical characteristics of apoptosis were observed.On this basis,this paper intends to further use isoimperatorin to treat BGC823 cell line.Analyzing the change of apoptosis of BGC823 cell line before and after the treatment of isoimperatorin through flow cytometry and Annexin V-FITC/PI Hoechst staining analysis.Using Western blot to detect the expression of PI3K,Akt,p-Akt,Bax,Bcl-2,Caspase-3 and Caspase-9 and to determine the signal pathway of apoptosis induced by isoimperatorin.Further,we set up the nude mice model with xenograft tumor to make sure whether isoimperatorin could inhibit the tumor and induce apoptosis of tumor cells,also we detected the expression of PI3K,Akt,p-Akt,Bax,Bcl-2,Caspase-3 and Caspase-9 in the xenograft tumor before and after isoimperatorin treatment.This study showed that the effect of isoimperatorin on gastric cancer cells and the important role of PI3K/Akt pathway,which provided new strategies and new targets for the genetic therapy for gastric cancer.