Mechanism of apoptotic effects induced selectively by ursodeoxycholic acid on human hepatoma cell lines.
OBJECTIVE
To investigate the effects of ursodeoxycholic acid (UDCA) on apoptosis and proliferation of hepatoma cell lines.


METHODS
Human hepatoma cell lines HepG2 and BEL 7402 were cultured in medium supplemented with different concentrations of UDCA, normal human hepatic line L-02 was used as control. Cell proliferation, apoptosis and gene expression were detected using methyl thiazolyl tetrazolium (MTT) assay, flow cytometry, Western blot, DNA ladder assay, electron microscopy, and immunocytochemistry.


RESULTS
Ursodeoxycholic acid inhibited the proliferation of HepG2 and BEL7402 cell lines in a dose-dependent manner. Ursodeoxycholic acid can change cell cycle distribution of HepG2 and BEL7402, the proportion of cells in G0-G1 phase increased whereas the proportion of S phase cells and G2-M phase cells decreased. Ursodeoxycholic acid arrested the cell cycle in G0-G1 phase by down-regulating the cell cycle related proteins cyclin D1, D3 and retinoblastoma protein (p(Rb)). The apoptotic rates of HepG2 and BEL7402 treated with UDCA (1.0 mmol/L) were significantly higher than those of control. In the HepG2 and BEL7402 treated with UDCA, expression of bcl-2 decreased whereas expression of Bax increased, the nuclear fragmentation and chromosomal condensed, cells shrank and lost attachment, apoptotic bodies and DNA ladders appeared. UDCA had no effect in inducing apoptosis on L-02 cell lines.


CONCLUSIONS
UDCA can selectively inhibit proliferation and induce apoptosis of HepG2 and BEL7402 cell lines by blocking cell cycle and regulating the expression of Bax/bcl-2 genes.
Liu
Hui
H
Department of Gastroenterology, Shandong Provincial Hospital Shandong University, Jinan 250021, Shandong Province, China. h_liu13@yahoo.com.cn
Qin
Cheng-Yong
CY
Han
Guo-Qing
GQ
Xu
Hong-Wei
HW
Meng
Mei
M
Yang
Zhen
Z
D017209:Apoptosis / Q000187:drug effects*; D006528:Carcinoma, Hepatocellular / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D002453:Cell Cycle / Q000187:drug effects; D002460:Cell Line; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002756:Cholagogues and Choleretics / Q000494:pharmacology*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism; D016213:Cyclins / Q000235:genetics / Q000378:metabolism; D053938:DNA Fragmentation; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008099:Liver / Q000166:cytology / Q000378:metabolism / Q000473:pathology; D008113:Liver Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism; D014580:Ursodeoxycholic Acid / Q000494:pharmacology*; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism
C493956:CDKN1A protein, human; D002756:Cholagogues and Choleretics; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D014580:Ursodeoxycholic Acid