Effect of pseudolaric acid B on gastric cancer cells: inhibition of proliferation and induction of apoptosis.
OBJECTIVE
To examine the effect of pseudolaric acid B on the growth of human gastric cancer cell line, AGS, and its possible mechanism of action.


METHODS
Growth inhibition by pseudolaric acid B was analyzed using MTT assay. Apoptotic cells were detected using Hoechst 33258 staining, and confirmed by DNA fragmentation analysis. Western blot was used to detect the expression of apoptosis-regulated gene Bcl-2, caspase 3, and cleavage of poly (ADP-ribose) polymerase-1 (PARP-1).


RESULTS
Pseudolaric acid B inhibited the growth of AGS cells in a time- and dose-dependent manner by arresting the cells at G(2)/M phase, which was accompanied with a decrease in the levels of cdc2. AGS cells treated with pseudolaric acid B showed typical characteristics of apoptosis including chromatin condensation and DNA fragmentation. Moreover, treatment of AGS cells with pseudolaric acid B was also associated with decreased levels of the anti-apoptotic protein Bcl-2, activation of caspase-3, and proteolytic cleavage of PARP-1.


CONCLUSIONS
Pseudolaric acid B can dramatically suppress the AGS cell growth by inducing apoptosis after G(2)/M phase arrest. These findings are consistent with the possibility that G(2)/M phase arrest is mediated by the down-regulation of cdc2 levels. The data also suggest that pseudolaric acid B can trigger apoptosis by decreasing Bcl-2 levels and activating caspase-3 protease.
Li
Ke-Shen
KS
Department of Epidemiology, Harbin Medical University, Harbin 150086, Heilongjiang Province, China.
Gu
Xue-Feng
XF
Li
Ping
P
Zhang
Yong
Y
Zhao
Ya-Shuang
YS
Yao
Zhen-Jiang
ZJ
Qu
Nai-Qiang
NQ
Wang
Bin-You
BY
D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D053938:DNA Fragmentation / Q000187:drug effects; D004224:Diterpenes / Q000494:pharmacology*; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D005434:Flow Cytometry; D006801:Humans; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000473:pathology
D004224:Diterpenes; D004365:Drugs, Chinese Herbal; D019253:Proto-Oncogene Proteins c-bcl-2; C058391:pseudolaric acid B; D011065:Poly(ADP-ribose) Polymerases; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases