Abstract 2586: Pomegranate components modulate distinct pathways in prostate cancer cells

Abstract

Abstract Pomegranate juice, when provided as whole juice, modulates specific pathways in prostate cancer cells that are not reflected when its major constituents were tested independently. In order to identify these bioactive components of pomegranate, the peel (P) and arils (J) were isolated, juiced separately and extracted with 80% methanol (PE and JE). The components were enriched using a SPE C18 cartridge and, eluted as fraction I (P-I and J-I - contains mostly polar compounds) and fraction II (P-II and J-II - contains mostly non-polar compounds). Analysis by HPLC-PDA and by direct infusion analysis of these fractions by FTICR-MS revealed the J-I consisted of mostly phenolics including the three anthocyanins in its mono- and di-glycoside forms. P-I consisted mostly of punicalin and, the punicalagins A and B, while P-II and J-II consisted mostly of ellagitannins and free ellagic acid. The ORAC values as Trolox equivalent for the various fractions at 10 µg/ml were: Total peel extract (PE) - 1.64 compared with 2.74 for P-I and 4.01 for P-II, while for the total juice extract (JE) it was 2.62 compared with 7.01 for J-I and 5.47 for J-II. To identify the molecular mechanisms, the individual fractions of peel and juice were tested in prostate cancer cell lines, LNCaP and PC3 and analyzed by Cancer/Apoptosis Phospho Antibody Array and western blot analysis. In LNCaP cell line, BCL-2, PTEN, Cdc25A, p53 and STAT6 were hyper-phosphorylated by J-II, while they were unaltered by J-I. Similarly, GSK3 alpha and beta were hyper-phosphorylated by J-I and unmodified by J-II. When peel fractions were tested, Cdc25C, BCL-2, CREB and JAK were hypo-phosphorylated by P-II, whereas they were unaltered by P-I. Other molecules, such as IRS-1, MAP Kinase, PTEN, STAT3 and JAK2 were hypo-phosphorylated by P-II, and were hyper-phosphorylated by P-I. In PC3 cell line, BCL-2, p53 and CREB were hypo-phosphorylated by J-II, while they were unaltered by J-I. However, PTEN and p70 were hypo-phosphorylated by J-II and hyper-phosphorylated by J-I, while, CDK2, STATs 1, 3 and 6 were hypo-phosphorylated by P-II, they were unaltered by P-I fraction. Thus the components of peel and juice fractions demonstrate unique properties and the ability to modulate distinct pathways in androgen-dependent and independent prostate cancer cells providing a rich set of potential therapy or adjuvant applications. This work is supported by NCI grant CA143676. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2586. doi:1538-7445.AM2012-2586