Rocaglaol induces apoptosis and cell cycle arrest in LNCaP cells
Mi, Q.; Su, B-Ning.; Chai, H.; Cordell, G.A.; Farnsworth, N.R.; Kinghorn, A.Douglas.; Swanson, S.M.
Anticancer Research 26(2a): 947-952
2006
ISSN/ISBN: 0250-7005 PMID: 16619491 Document Number: 604455
Rocaglaol is a cytotoxic cyclopentabenzofuran isolated from the bark of Aglaia crassinervia. It exhibited in vitro cytotoxic activity against Lu1, LNCaP and MCF-7 cells with ED50 values of 13.8, 23.0 and 9.2 nM, respectively. DAPI staining indicated that LNCaP cells treated with rocaglaol underwent apoplosis. In order to determine whether rocaglaol-induced apoptosis is mediated by the mitochondrial pathway, apoptosis-related mitochondrial-associated protein, were studied. Rocaglaol treatment induced Bax expression through 12 to 72 h of exposure, while Bcl-xl expression was slightly decreased through 48 h, and decreased more significantly by 72 h. Cleaved caspase-9 expression way detected at 72 h, and cleaved caspase-7 was increased through 48 to 72 h. Consequently, the large fragment (89 kDa) of PARP resulting from caspase cleavage was detected at 12, 24 and 48 h, and especially at 72 h. Cleaved PARP expression was also detected at 72 h. Since rocaglaol caused dose-dependent G(2)/M phase arrest of LNCaP cells as indicated by flow cytometric analysis, the protein levels of cell cycle-related genes were measured. Rocaglaol treatment (230 nM) did not change cyclin B after 24- to 60-h treatment. The expression of cdc2 was not changed and phospho-cdc2 (Tyr 15) increased after 36-, 48- and 60-h treatment. hi addition, protein phosphatase Cdc25C, which functions as a mitotic activator by dephosphotylation of Cdc2, decreased in a time-dependent manner after rocaglaol treatment. Taken together, these results suggest that rocaglaol is a potent anticancer drug that induces apoptosis of LNCaP cells through the mitochondrial pathway and its G(2)/M-phase cell cycle arrest is associated with the down-regulation of Cdc25C and the dephosphorylation of Cdc2.