Abstract #34: Colored potato functional compounds suppress insulin-like growth factor-1-promoted prostate cancer cell proliferation and elevate apoptosis through activation of p53 and suppression of IGF-1R/Akt pathways.

Prostate cancer is the second leading cause of cancer death among men in the US. The insulin-like growth factor (IGF) system promotes proliferation of prostate cancer cells. Also, IGF-I levels are elevated in obese men and correlate with an increased risk of prostate cancer. We previously showed that colored potato extracts suppress prostate cancer (LNCaP) cell proliferation and induce apoptosis via both caspase-dependent and independent pathways; however, the role of potato functional compounds against IGF-1 promoted growth of prostate cancer cells is unknown. In this study, we investigated the role of whole potato extract and the anthocyanin fraction on LNCaP cell proliferation and apoptosis in the presence/absence of IGF-1. IGF-1 (10 nM) increased LNCaP cell proliferation compared to the control. The potato extract and anthocyanin fraction (5\#956;g/ml) suppressed IGF-1 stimulated proliferation. Whole potato extract and the anthocyanin fraction (5-10 \#956;g/ml) induced apoptosis in LNCaP cells, even in the presence of IGF-1. The anti-proliferative properties of potato extract and anthocyanin fraction in the presence of IGF-1 was mediated by increased p27 levels and suppressed cyclin D1 levels. The extracts also increased the phosphorylated p53 levels and suppressed IGF-1R and Akt signaling pathways. Our results suggest that potato extract and the anthocyanin fraction are potent inhibitors of IGF-1 induced cell proliferation and IGF-1R signaling in prostate cancer cells in vitro. We are currently evaluating the chemo-preventive properties of colored potatoes against obesity-enhanced prostate carcinogenesis using in vivo models

Citation Information: In: Proc Am Assoc Cancer Res; 2009 Apr 18-22; Denver, CO. Philadelphia (PA): AACR; 2009. Abstract nr 34.