Prostate cancer has its highest incidence in the USA and is becoming a major concern in Asian countries. Bufadienolides are extracts of toxic glands from toads and are used as anticancer agents, mainly on leukemia cells. In the present study, the antiproliferative and apoptotic mechanisms of bufalin and cinobufagin on prostate cancer cells were investigated. Proliferation of LNCaP, DU145, and PC3 cells was measured by 3‐(4,5‐dimethylthiazol‐2‐yle)‐2,5‐diphenyltetrazolium bromide assay and the doubling time (tD) was calculated. Bufalin and cinobufagin caused changes in the tD of three prostate cancer cell lines, which were more significant than that of human mesangial cells. In addition, bufadienolides induced prostate cancer cell apoptosis more significantly than that in breast epithelial cell lines. After treatment, the caspase‐3 activity and protein expression of caspase‐3, ‐8, and ‐9 were elevated. The expression of other apoptotic modulators, including mitochondrial Bax and cytosolic cytochrome c, were also increased. However, expression of p53 was only enhanced in LNCaP cells. Downregulation of p53 by antisense TP53 restored the cell viability suppressed by bufalienolides. Furthermore, the increased expression of Fas was more significant in DU145 and PC3 cells with mutant p53 than in LNCaP cells. Transfection of Fas small interfering RNA restored cell viability in the bufadienolide‐treated cells. These results suggest that bufalin and cinobufagin suppress cell proliferation and cause apoptosis in prostate cancer cells via a sequence of apoptotic modulators, including Bax, cytochrome c, and caspases. The upstream mediators might be p53 and Fas in androgen‐dependent LNCaP cells and Fas in androgen‐independent DU145 and PC3 cells. (Cancer Sci 2008; 99: 2467–2476)

(2013). Inhibitory effects of isoliquiritigenin on the migration and invasion of human breast cancer cells. Expert Opinion on Therapeutic Targets: Vol. 17, No. 4, pp. 337-349.

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.