Gypenosides induced G0/G1 arrest via CHk2 and apoptosis through endoplasmic reticulum stress and mitochondria-dependent pathways in human tongue cancer SCC-4 cells.
Gypenosides (Gyp), a component of Gynostemma pentaphyllum Makino, was selected for examining the effects on the cell viability, cell cycle and induction of apoptosis in human tongue cancer SCC-4 cells. Gyp induced cytotoxicity (decreased the percentage of viable cells) in SCC-4 cells appeared to be associated with induction of cell cycle arrest (G0/G1 arrest), apoptotic cell death based on Gyp induced morphological changes and DNA fragmentation and increased the sub-G1 group in examined SCC-4 cells. The production of reactive oxygen species and Ca(2+) and the depolarization of mitochondrial membrane potential were observed, dose- and time-dependently, after treatment of SCC-4 cells with various concentrations of Gyp. Gyp inhibited the levels of the anti-apoptotic proteins Bcl-2 and Bcl-xl, but promoted the levels of the pro-apoptotic protein Bax. Western blotting showed the releases of cytochrome c and Endo G and both were also confirmed by confocal laser microscopic systems. The GADD153 moved to nuclei (nuclear translocation). In conclusion, Gyp induced ER stress and production of reactive oxygen species and Ca(2+), change the ratio of Bcl-2 and Bax, followed by the dysfunction of mitochondria, caused cytochrome c release, activation of caspase-3 before leading to apoptosis. These results provide information towards an understanding of the mechanisms by which Gyp induces cell cycle arrest and apoptosis in human tongue cancer cells.
Chen
Jung-Chou
JC
Graduate Institute of Chinese Medical Science, China Medical University, Taichung, Taiwan.
Lu
Kung-Wen
KW
Tsai
Ming-Li
ML
Hsu
Shu-Chun
SC
Kuo
Chao-Lin
CL
Yang
Jai-Sing
JS
Hsia
Te-Chun
TC
Yu
Chun-Shu
CS
Chou
Su-Tze
ST
Kao
Ming-Ching
MC
Chung
Jing-Gung
JG
Wood
W Gibson
WG
D017209:Apoptosis / Q000187:drug effects*; D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004721:Endoplasmic Reticulum / Q000473:pathology; D016193:G1 Phase / Q000187:drug effects; D029774:Gynostemma; D006801:Humans; D008928:Mitochondria / Q000473:pathology; D010936:Plant Extracts / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors; D017382:Reactive Oxygen Species / Q000378:metabolism; D016192:Resting Phase, Cell Cycle / Q000187:drug effects; D014062:Tongue Neoplasms / Q000473:pathology*; D051028:bcl-2-Associated X Protein / Q000096:biosynthesis; D051020:bcl-X Protein / Q000037:antagonists & inhibitors
D010936:Plant Extracts; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; C474918:gypenoside