Vol. 300, Issue 2, 535-542, February 2002

Prevention of Lipopolysaccharide-Induced Apoptosis by (2S,3S,4R)-N"-Cyano-N-(6-amino-3,4-dihydro-3-hydroxy-2-methyl-2-dimethoxymethyl-2H-benzopyran-4-yl)-N'-benzylguanidine, a Benzopyran Analog, in Endothelial Cells

Ki Young Kim, Byeong Gee Kim, Sun-Ok Kim, Sung-Eun Yoo, Yong-Geun Kwak, Soo-Wan Chae and Ki Whan Hong

Department of Pharmacology (K.Y.K., K.W.H.), College of Medicine and College of Natural Sciences (B.G.K.), Pusan National University, Pusan, Korea; Central Research Institute, Dongbu Hannong Chemical Co., Daejon, Korea (S.-O.K.); Research Institute of Chemical Technology, Daejon, Korea (S.-E.Y.); and Institute of Cardiovascular Research, Chonbuk National University, Chonju Korea (Y.-G.K., S.-W.C.)

This study describes the antiapoptotic action of (2S,3S,4R)-N"-cyano-N-(6-amino-3,4-dihydro-3-hydroxy-2-methyl-2-dimethoxymethyl-2H-benzopyran-4-yl)-N'-benzylguanidine (KR-31378), a novel benzopyran analog, in human umbilical vein endothelial cells (HUVECs) in comparison with its acetylated metabolite, (2S,3S,4R)-N"-cyano-N-(6-acetylamino-3,4-dihydro-3-hydroxy-2-methyl-2-dimethoxymethyl-2H-benzopyran-4-yl)-N'-benzylguanidine (KR-31612), and with -tocopherol. Exposure of HUVECs to lipopolysaccharide (LPS) (1 µg/ml) induced time- and concentration-dependent cytotoxicity and oligonucleosomal DNA fragmentation. KR-31378, KR-31612, and -tocopherol potently suppressed LPS-induced cell death in association with significant reduction in the intracellular reactive oxygen species (ROS) and tumor necrosis factor- (TNF-) that are stimulated by LPS. KR-31378 more effectively protected HUVECs from LPS-induced DNA fragmentation and was more effective in peroxyl radical scavenging than -tocopherol. Incubation with LPS markedly decreased the Bcl-2 level, which was totally reversed by KR-31378 and to a lesser degree by KR-31612 and by -tocopherol. In contrast, the greatly increased Bax protein and cytochrome c release stimulated by LPS were markedly suppressed by KR-31378 and by KR-31612, and to a lesser degree by -tocopherol. Taken together, KR-31378 strongly inhibited cell death in HUVECs in association with antiapoptotic effects, which were accompanied by up-regulation of Bcl-2 protein expression and down-regulation of Bax protein and suppression of cytochrome c release. KR-31378 also showed the properties to scavenge the intracellular ROS and peroxyl radicals, and to reduce the TNF- production induced by LPS.