Curcumin inhibits growth of prostate carcinoma via miR-208-mediated CDKN1A activation.

Prostate cancer (PC) is a prevalent cancer in aged men. Curcumin is an active ingredient that has been extracted from the rhizome of the plant Curcuma longa. Recently, a potential of Curcumin against PC has been reported in PC, whereas the underlying molecular mechanisms are not completely understood. Here, we studied the effects of low-dose Curcumin on PC cell growth. Curcumin (from 0.2 to 0.8 μmol/l) dose-dependently inhibited the proliferation of PC cells, without affecting cell apoptosis. Further analyses showed that Curcumin dose-dependently increased a cell cycle suppressor CDKN1A at protein levels, but not mRNA levels, in PC cells, suggesting that Curcumin may regulate the translation of CDKN1A, as well as a possible involvement of miRNA intervention. From all CDKN1A-3'-UTR-binding miRNAs, we found that miR-208 was specifically inhibited in PC cells dose-dependently by Curcumin. Moreover, miR-208 was found to bind CDKN1A to suppress its expression. In a loss-of-function experiment, PC cells that overexpressed miR-208 failed to decrease cell proliferation in response to Curcumin. Together, these data suggest that Curcumin inhibits growth of PC via miR-208-mediated CDKN1A activation.