Ergosta-4,6,8(14),22-tetraen-3-one induces G2/M cell cycle arrest and apoptosis in human hepatocellular carcinoma HepG2 cells.
BACKGROUND
Mushrooms have been used in Asia as traditional foods and medicines for a long time. Ergosta-4,6,8(14),22-tetraen-3-one (ergone) is one of the well-known bioactive steroids, which exists widely in various medicinal fungi such as Polyporus umbellatus, Russula cyanoxantha, and Cordyceps sinensis. Ergone has been demonstrated to possess cytotoxic activity. However, the molecular mechanisms by which ergone exerts its cytotoxic activity are currently unknown.


METHODS
In the present study, ergone possessed a remarkable anti-proliferative activity toward human hepatocellular carcinoma HepG2 cells. We assayed the cell cycle by flow cytometry using PI staining; investigated the exposure of phosphatidylserine at the outer layer of the cytoplasmic membrane by the FITC-annexin V/PI staining; observed the nuclear fragmentation by Hoechst 33258 staining and studied the protein expression of Bax, Bcl-2, p-53, procaspase-3, -8, -9, PARP and cleaved PARP by Western blotting analysis.


RESULTS
Cells treated with ergone showed typical markers of apoptosis: G2/M cell cycle arrest, chromatin condensation, nuclear fragmentation, and phosphatidylserine exposure. Furthermore, PARP-cleavage; activation of caspase-3, -8, -9; up-regulation of Bax and down-regulation of Bcl-2 were observed in HepG2 cells treated with ergone, which show that both the intrinsic and extrinsic apoptotic pathways are involved in ergone-induced apoptosis in HepG2 cells. Ergosta-4,6,8(14),22-tetraen-3-one induces G2/M cell cycle arrest and apoptosis in HepG2 cells in a caspase-dependent manner.


CONCLUSIONS
In this study, we reported for the first time that ergone-induced apoptosis through activating the caspase. These results would be useful for the further utilization of many medicinal fungi in cancer treatment.
Biomedicine Key Laboratory of Shaanxi Province, Northwest University, No.229 Taibai North Road, Xi'an, Shaanxi 710069, China.
Ying-Yong
YY
Zhao
Xuefeng
X
Shen
Xu
X
Chao
Charlene C
CC
Ho
Xian-Long
XL
Cheng
Yongmin
Y
Zhang
Rui-Chao
RC
Lin
Ke-Jun
KJ
Du
Wen-Jing
WJ
Luo
Jing-Yuan
JY
Chen
Wen-Ji
WJ
Sun
D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000302:isolation & purification / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy*; D002453:Cell Cycle / Q000187:drug effects*; D002783:Cholestenones / Q000138:chemical synthesis / Q000302:isolation & purification / Q000494:pharmacology*; D056945:Hep G2 Cells; D006801:Humans; D055492:Polyporus / Q000737:chemistry*
D000970:Antineoplastic Agents; D002783:Cholestenones; C015860:ergosta-4,6,8(14),22-tetraen-3-one