Regulation of apoptosis in human gastric cancer cell line SGC-7901 by L-arginine.

Aim: L-arginine (LArg) is an amino acid that has immunomodulating and anti-tumor effects. It is possible that anti-tumor effects of L-Arg are due to induction of apoptosis in tumor cells. The present study assessed anti-proliferating and pro-apoptotic effects of L-Arg in human gastric cancer cell line SGC7901. Methods: Cell proliferation was quantified by MTT assay. Apoptosis was assessed using flow cytometry and FITCAnnexinV/ propidium iodide staining. Expression and activation of proteins pertinent to apoptosis (Bcl2, surviving, p53, and XIAP) were studied using PCR, Western blot, and activity assays. Results: L-Arg significantly inhibited growth of SCG-7901 gastric cancer cells and down-regulated expression of anti-apoptotic gene Bcl-2 and survivin. By contrast, expression of p53 was upregulated by L-Arg. Conclusion: Regulation of apoptosis by L-Arg via down-regulation of anti-apoptotic proteins Bcl-2 and surviving, and up-regulation of pro-apoptotic protein p53 may represent the mechanism behind antitumor effects of L-Arg.