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

Aim. L-arginine (L-Arg) is an aminoacid that has immunomodulating and antitumor effects. It is possible that antitumor effects of L-Arg are due to induction of apoptosis in tumor cells. The present study assessed antiproliferating and proapoptotic effects of L-Arg in human gastric cancer cell line SGC-7901. Methods. Cell proliferation was quantified by MTT assay. Apoptosis was assessed using flow cytometry and FITC-Annexin-V/propidium iodide staining. Expression and activation of proteins pertinent to apoptosis (Bcl-2, 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 downregulated expression of antiapoptotic gene Bcl-2 and survivin. By contrast, expression of p53 was upregulated by L-Arg. Conclusion. Regulation of apoptosis by L-Arg via downregulation of antiapoptotic proteins BcI-2 and surviving, and upregulation of proapoptotic protein p53 may represent the mechanism behind antitumor effects of L-Arg.