Title: Differential effects of black raspberry and strawberry extracts on BaPDE-induced activation of transcription factors and their target genes.
Authors: Li, Jingxia; Zhang, Dongyun; Stoner, Gary D; Huang, Chuanshu
Published In Mol Carcinog, (2008 Apr)
Abstract: The chemopreventive properties of edible berries have been demonstrated both in vitro and in vivo, however, the specific molecular mechanisms underlying their anti-cancer effects are largely unknown. Our previous studies have shown that a methanol extract fraction of freeze-dried black raspberries inhibits benzoapyrene (BaP)-induced transformation of Syrian hamster embryo cells. This fraction also blocks activation of activator protein-1 (AP-1) and nuclear factor kappaB (NF-kappaB) induced by benzoapyrene diol-epoxide (BaPDE) in mouse epidermal JB6 Cl 41 cells. To determine if different berry types exhibit specific mechanisms for their anti-cancer effects, we compared the effects of extract fractions from both black raspberries and strawberries on BaPDE-induced activation of various signaling pathways in Cl 41 cells. Black raspberry fractions inhibited the activation of AP-1, NF-kappaB, and nuclear factor of activated T cells (NFAT) by BaPDE as well as their upstream PI-3K/Akt-p70(S6K) and mitogen-activated protein kinase pathways. In contrast, strawberry fractions inhibited NFAT activation, but did not inhibit the activation of AP-1, NF-kappaB or the PI-3K/Akt-p70(S6K) and mitogen-activated protein kinase pathways. Consistent with the effects on NFAT activation, tumor necrosis factor-alpha (TNF-alpha) induction by BaPDE was blocked by extract fractions of both black raspberries and strawberries, whereas vascular endothelial growth factor (VEGF) expression, which depends on AP-1 activation, was suppressed by black raspberry fractions but not strawberry fractions. These results suggest that black raspberry and strawberry components may target different signaling pathways in exerting their anti-carcinogenic effects.
PubMed ID: 18085529
MeSH Terms: 7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide/pharmacology*; Animals; Anticarcinogenic Agents/chemistry; Carcinogens/pharmacology; Cell Line; Cricetinae; Fragaria*/chemistry; Fragaria*/physiology; Fruit/chemistry; Fruit/physiology; Gene Expression Regulation, Neoplastic/drug effects*; Mice; NF-kappa B/drug effects; Plant Extracts/chemistry; Plant Extracts/pharmacology*; Transcription Factor AP-1/antagonists & inhibitors; Transcription Factor AP-1/metabolism*; Transcription Factors/metabolism*