Abstract
American cranberry (Vaccinium macrocarpon) extract has been previously shown to affect cell cycle, apoptosis, and proliferative ability in prostate cancer cells in vitro. The insulin-like growth factors (IGFs) and their modulators the insulin-like growth factor binding proteins (IGFBPs) may play roles in these events. IGFBPs act by regulating IGF action but also exhibit many IGF-independent activities. IGFBP expression in response to cranberry extract [50 & 100 ug/mL for 3 and 24 hours] was determined via Western blot analysis in DU145 and in PC3 androgen-refractory human prostate cancer cells. Cranberry extract treatment decreased the expression levels of both IGFBP-2 and IGFBP-5 and increased the expression levels of IGFBP-4. IGFBP-3 protein expression levels were apparently unaffected by cranberry extract suggesting that IGFBP-3 is likely not involved in this cellular response to cranberry extract. A reduction in IGFBP-2/-5 expression suggests a reduction in IGF through loss of IGF-stabilization by the IGFBPs suggesting an inhibition of the cell cycle due to this restriction in IGF. Increases in IGFBP-4 levels in response to cranberry would also inhibit IGFs and thereby inhibit cellular growth and proliferation. Increased IGFBP-2/-5 expression has been associated with progression from androgen-sensitivity to androgen-insensitivity in prostate cancer cells. Decreased IGFBP-2/-5 expression levels in response to cranberry extract could counteract this progression in vitro. [funded by The Cranberry Institute (Wisconsin Board) and Jeanne & J.-Louis Levesque Foundation] Citation Format: Robert Hurta, Brendan McKeown, Ravi Boddeti, Catherine Neto. Modulation of insulin-like growth factor binding proteins expression in human prostate cancer cells in vitro by american cranberry (Vaccinium macrocarpon) extract. [abstract]. In: Proceedings of the Third AACR International Conference on Frontiers in Basic Cancer Research; Sep 18-22, 2013; National Harbor, MD. Philadelphia (PA): AACR; Cancer Res 2013;73(19 Suppl):Abstract nr B22.