Yu-Jie Yang1, She-Ning Qi2, Rui-Yue Shi1, Jun Yao1, Li-Sheng Wang3, Hu-Qin Yuan4, Yuan-Xue Jing5. 1. Department of Gastroenterology, The Second Clinical Medical College, Jinan University, Shenzhen 518020, China. 2. Department of Histology and Embryology, School of Basic Medicine, Lanzhou University, Key Laboratory of Pre-clinical Study for New Drugs of Gansu Province, Lanzhou 730000, China. Electronic address: qishn@lzu.edu.cn. 3. Department of Gastroenterology, The Second Clinical Medical College, Jinan University, Shenzhen 518020, China. Electronic address: wangls168@163.com. 4. Department of Gastrointestinal Oncology Surgery, Tumor Hospital of Gansu Province, Lanzhou 730050, China. 5. Reproductive Hospital, The First Clinical Medical College, Lanzhou University, Lanzhou 730000, China.
Abstract
PURPOSE: 4-[4''-(2'', 2'', 6'', 6''-tetramethyl-l''-piperidinyloxy) amino]-4'-demethyl-epipodophyllotoxin (GP7) is a new semi-synthesized nitroxyl spin-labeled derivative of podophyllotoxin with anti-leukemic and anti-osteosarcoma effects. The purpose of the present study is to investigate the anti-gastric cancer (GC) effects of GP7 and the possible involvement of caspase pathway in GP7-induced apoptotic DNA fragmentation in human GC cells. MATERIALS AND METHODS: Effects of GP7 on the proliferation of human GC cell lines MKN28, AGS, BGC-823 and HGC-27 in different degrees of differentiation and normal human gastric epithelial cell line GES-1 were studied by MTT assay and compared with the effects of etoposide. Effects of GP7 on cell viability and heat shock protein 90 expression of BGC-823 and HGC-27 cells were analyzed by trypan blue exclusion test and western blotting, respectively. Effects of GP7 on apoptotic DNA fragmentation and caspase pathway of BGC-823 and HGC-27 cells were detected by agarose gel electrophoresis, colorimetric assay and western blotting. Caspase-3 inhibitor was used to manipulate the activity of caspase-3. RESULTS: GP7 inhibited concentration- and time-dependently the proliferation of human GC cells, and the inhibitory effect of GP7 on the proliferation of BGC-823 or HGC-27 cells was 1.15- or 1.21-fold higher than that of etoposide. GP7 downregulated heat shock protein 90, improved the anti-GC effects of adriamycin, cisplatin, 5-fluorouracil and their combinations, induced apoptotic DNA fragmentation, activations of caspase-9 and -3 but not -8, cytochrome-c release and BID cleavage in BGC-823 and HGC-27 cells. Caspase-3 inhibitor abrogated GP7-induced BID cleavage, decreased cytochrome-c release, caspase-9 and -3 activities and apoptotic DNA fragmentation but increased cell viability in BGC-823 and HGC-27 cells. CONCLUSION: Our findings indicate that GP7 is a promising anti-GC derivative of podophyllotoxin, and GP7-induced apoptosis in human GC cells may be mediated by mitochondrial pathway with caspase-3-dependent BID cleavage.
PURPOSE: 4-[4''-(2'', 2'', 6'', 6''-tetramethyl-l''-piperidinyloxy) amino]-4'-demethyl-epipodophyllotoxin (GP7) is a new semi-synthesized nitroxyl spin-labeled derivative of podophyllotoxin with anti-leukemic and anti-osteosarcoma effects. The purpose of the present study is to investigate the anti-gastric cancer (GC) effects of GP7 and the possible involvement of caspase pathway in GP7-induced apoptotic DNA fragmentation in human GC cells. MATERIALS AND METHODS: Effects of GP7 on the proliferation of human GC cell lines MKN28, AGS, BGC-823 and HGC-27 in different degrees of differentiation and normal human gastric epithelial cell line GES-1 were studied by MTT assay and compared with the effects of etoposide. Effects of GP7 on cell viability and heat shock protein 90 expression of BGC-823 and HGC-27 cells were analyzed by trypan blue exclusion test and western blotting, respectively. Effects of GP7 on apoptotic DNA fragmentation and caspase pathway of BGC-823 and HGC-27 cells were detected by agarose gel electrophoresis, colorimetric assay and western blotting. Caspase-3 inhibitor was used to manipulate the activity of caspase-3. RESULTS: GP7 inhibited concentration- and time-dependently the proliferation of human GC cells, and the inhibitory effect of GP7 on the proliferation of BGC-823 or HGC-27 cells was 1.15- or 1.21-fold higher than that of etoposide. GP7 downregulated heat shock protein 90, improved the anti-GC effects of adriamycin, cisplatin, 5-fluorouracil and their combinations, induced apoptotic DNA fragmentation, activations of caspase-9 and -3 but not -8, cytochrome-c release and BID cleavage in BGC-823 and HGC-27 cells. Caspase-3 inhibitor abrogated GP7-induced BID cleavage, decreased cytochrome-c release, caspase-9 and -3 activities and apoptotic DNA fragmentation but increased cell viability in BGC-823 and HGC-27 cells. CONCLUSION: Our findings indicate that GP7 is a promising anti-GC derivative of podophyllotoxin, and GP7-induced apoptosis in human GC cells may be mediated by mitochondrial pathway with caspase-3-dependent BID cleavage.