Induction of cell cycle arrest in DU145 human prostate cancer cells by the dietary compound isoliquiritigenin (ISL)

Abstract

Piceatannol (3,4,3′,5′‐tetrahydroxystilbene) is a naturally occurring polyphenol and analog of the cancer chemopreventive agent resveratrol (3,5,4′‐trihydroxystilbene). Piceatannol is present in the skins of grapes, rhubarb, and sugar cane and is known to have anti‐inflammatory and anti‐carcinogenic activity. In the present study, we examined piceatannol‐mediated regulation of cell cycle progression in androgen‐insensitive DU145 human prostate cancer cells. Cells were treated with 0–10 μM piceatannol. The percentage of cells in G1 phase was increased in cells treated with piceatannol for 24 h. Piceatannol decreased incorporation of [3H]thymidine into DNA. Piceatannol decreased the protein levels of cyclin A, and cyclin D1. In addition, cyclin‐dependent kinase (CDK)2 and CDK4 protein levels decreased in cell treated with piceatannol. But piceatannol did not affect the expression of the CDK inhibitor p21 or p27. The activity of CDK2 and CDK4 decreased following piceatannol treatment in a concentration‐dependent manner. The present results indicate that piceatannol inhibits the growth of DU145 cell growth by delaying G1 cell cycle progression, which may be mediated via inhibition of CDK activities.