Inhibitory effects of evodiamine on the growth of human prostate cancer cell line LNCaP.

Abstract

Evodiamine, isolated from a Chinese herbal drug named Wu-Chu-Yu, possesses many biological functions. Recently, it has been reported that Wu-Chu-Yu exerts an antiproliferative effect on several cancers. Prostate carcinoma initially occurs as an androgen-dependent tumor and is the second leading cause of cancer death in American males. In the present study, the effect of evodiamine on the growth of androgen-dependent prostate cancer cell line LNCaP in vitro was examined. Based on [3-(4,5-dimethylthiazol-2-yle)2,5-diphenyltetrazolium bromide] (MTT) assay, evodiamine significantly inhibited the growth of LNCaP cells in a concentration-dependent manner. A significant and concentration-dependent inhibitory effect of evodiamine on LNCaP cell growth was observed at 24 hr and persisted for 96 hr. The examination of lactate dehydrogenase (LDH) assay showed that the cytotoxic effects of evodiamine on LNCaP cells were concentration dependent. Furthermore, we examined the influences of evodiamine on cell death and cell cycle. The flow cytometric analysis of evodiamine-treated cells indicated a block of G2/M phase and an elevated level of DNA fragmentation. The G2/M arrest reached a maximum at 24 hr after evodiamine treatment. The G2/M arrest was accompanied by an elevated p34(cdc2) kinase activity and an increase in the protein expression of cyclin B1 and phosphorylated form of p34(cdc2) (Thr 161). Examination of TUNEL showed that evodiamine-induced apoptosis was observed at 24 hr and extended for 72 hr. Evodiamine elevated caspase-3, and caspase-9 activities and the processing of caspase-3 and caspase-9. These results suggested that evodiamine inhibits the growth of prostate cancer cell line, LNCaP, through an accumulation of cell cycle at G2/M phase and an induction of apoptosis.