Potent inhibitory effect of terpenoids from Acanthopanax trifoliatus on growth of PC-3 prostate cancer cells in vitro and in vivo is associated with suppression of NF-κB and STAT3 signalling

Five terpenoids ( 1 – 5 ) from a vegetable plant Acanthopanax trifoliatus (L.) Merr. were investigated for their effects on human prostate cancer cells. The diterpenoid ( 3 ) and triterpenoids ( 4 and 5 ) were found to inhibit the growth and stimulate apoptosis in PC-3 cells. The effects of these terpenoids on PC-3 cells were associated with strong suppression of nuclear factor-κB (NF-κB) and signal transducer and activator of transcription 3 (STAT3). These terpenoids also inhibited the expression of survivin, a downstream target of NF-κB and STAT3. The in vivo study using a xenograft mouse model showed that 5 strongly inhibited the formation and growth of PC-3 tumours. Moreover, treatment with 5 strongly decreased the expression of phospho-STAT3 and survivin in PC-3 tumours. Our results indicate that 5 has preventive efficacy on the development of PC-3 xenograft tumours. This terpenoid may serve as a candidate for future development as a novel agent for prostate cancer prevention.