Regulation of Bcl-2 family molecules and activation of caspase cascade involved in gypenosides-induced apoptosis in human hepatoma cells.
Herbal medicines are increasingly being utilized to treat a wide variety of disease processes. Gypenosides (Gyp) are triterpenoid saponins contained in an extract from Gynostemma pentaphyllum Makino and reported to induce apoptosis in human hepatoma cells. However, the molecular mechanism underlying the Gyp-induced apoptotic process is unclear. In this study, we found that Gyp induced apoptosis in human hepatoma Huh-7, Hep3B and HA22T cell lines as evidenced by morphological changes, 4',6'-diamidino-2-phenylindole staining and in situ terminal transferase-mediated dUTP-fluorescensin nick end-labeling assay. Our data demonstrated that Gyp-induced apoptotic cell death was accompanied by up-regulation of Bax, Bak and Bcl-X(L), and down-regulation of Bcl-2 and Bad, while it had no effect on the level of Bag-1 protein. Moreover, Gyp treatment caused the release of mitochondrial cytochrome c to cytosol and sequential activation of caspases, including caspase-1, -9 and -3, then leading to cleavage of poly-ADP-ribose polymerase. Furthermore, the Gyp-induced apoptosis was markedly blocked by the broad-spectrum caspase inhibitor, z-VAD-fmk. Taken together, these results suggest that treatment of human hepatoma cells with Gyp induced apoptosis through the up-regulation of Bax and Bak, and down-regulation of Bcl-2, release of mitochondrial cytochrome c and activation of caspase cascade.
Wang
Qwa Fun
QF
Institute of Chinese Medicine Sciences, China Medical College, Taichung, Taiwan, ROC.
Chen
Jung Chou
JC
Hsieh
Shur Jong
SJ
Cheng
Chi Chih
CC
Hsu
Shih Lan
SL
D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D017209:Apoptosis; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000473:pathology*; D002352:Carrier Proteins / Q000378:metabolism; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism*; D002470:Cell Survival; D002478:Cells, Cultured; D003574:Cytochrome c Group / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D015536:Down-Regulation; D006801:Humans; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D012503:Saponins / Q000378:metabolism*; D013997:Time Factors; D015854:Up-Regulation; D051025:bcl-Associated Death Protein
D000590:Amino Acid Chloromethyl Ketones; C494819:BAD protein, human; D002352:Carrier Proteins; D003574:Cytochrome c Group; D019253:Proto-Oncogene Proteins c-bcl-2; D012503:Saponins; D051025:bcl-Associated Death Protein; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases