Delphinidin, a dietary anthocyanidin in pigmented fruits and vegetables: A new weapon to blunt prostate cancer growth

Abstract

In a recent publication, we have shown that delphinidin, an anthocyanidin induces apoptosis and cell cycle arrest in highly metastatic human prostate cancer (PCa) PC3 cells. Extending these studies, we provide additional evidence that delphinidin induces apoptosis and cell cycle arrest in androgen refractory human PCa 22Rν1 cells and that these effects are concomitant with inhibition of NFκB. We observed that delphinidin treatment to 22Rν1 cells resulted in a dose-dependent (i) G2/M phase cell cycle arrest, (ii) induction of apoptosis (iii) and inhibition of NFκB signaling. The induction of apoptosis by delphinidin was mediated via activation of caspases since a general caspase inhibitor Z-VAD-FMK significantly reversed this effect. Delphinidin treatment to cells resulted in a dose-dependent decrease in (i) phosphorylation of IKKγ (NEMO), (ii) phosphorylation of NFκB inhibitory protein IκBα, (iii) phosphorylation of NFκB/p65 at Ser536 and NFκB/p50 at Ser529, (iv) NFκB/p65 nuclear translocation, and (v) NFκB DNA binding activity. Taken together, our data show that delphinidin induces apoptosis of both androgen independent and androgen refractory human PCa cells via activation of caspases and in addition, this effect might be due to inhibition of NFκB signaling. We suggest that delphinidin could be developed as a novel agent against PCa. ©2008 Landes Bioscience.