Study On The Inhibitory Effect Of Andrographolide On G2 / M Period Of Gastric Cancer SGC - 7901 Cells And The Apoptosis Of Mitochondrial Pathway

Andrographis paniculata is a medicinal plant traditionally used for treatment of cough and cold, fever, laryngitis, and several infectious diseases, including cancer. It’s shown the extracts, mainly Andrographolide, versatile potency against various diseases including cancer. Gastric carcinoma is a kind of high common malignancy, easily appears above 50. At present, the treatment of gastric carcinoma almost includes surgery therapy, radiotherapy and chemotherapy, but the curative effect of medicine of chemotherapy in conservative treatment is not satisfied. Therefore it’s a significance of finding new antineoplastic drugs. The emphasis of the paper is the design whether Andrographolide owns the ability of curing gastric cancer and that exploration of the mechanism.The MTT of 24h&48h treatment of Andrographolide with different concentration showed that Andrographolide inhibits growth of SGC-7901 cell in time and concentration dependent manner. It effectively inhibited SGC-7901 cell growth. IC50 was at 24 μg/ml for 48h. Through flow cytometry, we found the medicine arrested the cell cycle at G2/M phase and it induced apoptosis through intrinsic pathway. Hoechst 33258 staining proved it really induced apoptosis. Meanwhile the ROS level and mitochondria membrane potential also varied. The western blot demonstrated the change of related proteins of cell cycle and apoptosis. ATP&GSH level detection showed down-regulation after treatment with andrographolide. Addition of NADPH compensated cycle arresting, however β-naphthoflavone could enhance the cycle inhibition of andrographolide.Up-regulation of p53, and key proteins of G2/M check point; increase of p-cdc2 and decrease of Cyclin B1 showed andrographolide indeed inhibited cell cycle at G2/M phase. Meanwhile decrease of cdc 25 and increase of Chk2 demonstrated that G2/M phase arresting correlated with DNA damage. Then proof of andrographolide induced intrinsic apoptosis was supported by increase of Cleaved Caspase-3/9, cytochrome c, Bax as well as decrease of Bcl-2.Decline of ATP & GSH accord with result that flow cytometry detected that ROS increased and MMP collapsed. It could be recovered by ROS scavenger, NAC, and addition of NADPH. Moreover NADPH also compensated cell cycle inhibition and decreased p53, p-cdc2,Cleaved Caspase-9, Bax and increased Cyclin B1, Bcl-2. These indicated that cell cycle inhibition and apoptosis induction caused by andrographolide were related with ROS.In conclusion, Andrographolide inhibited SGC-7901 cell proliferation at G2/M phase through p53/cdc2/CyclinBl and Chk2/cdc25/cdc2 pathway, induced apoptosis through mitochondria intrinsic pathway by up-regulating ROS and then collapsing MMP.