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Differential effects of black raspberry and strawberry extracts on BaPDE‐induced activation of transcription factors and their target genes
Author(s) -
Li Jingxia,
Zhang Dongyun,
Stoner Gary D.,
Huang Chuanshu
Publication year - 2008
Publication title -
molecular carcinogenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 97
eISSN - 1098-2744
pISSN - 0899-1987
DOI - 10.1002/mc.20377
Subject(s) - biology , nfat , p70 s6 kinase 1 , transcription factor , microbiology and biotechnology , signal transduction , blowing a raspberry , protein kinase b , protein kinase a , kinase , biochemistry , gene , food science
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 κB (NF‐κB) 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‐κB, 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‐κB or the PI‐3K/Akt‐p70 S6K and mitogen‐activated protein kinase pathways. Consistent with the effects on NFAT activation, tumor necrosis factor‐α (TNF‐α) 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. © 2007 Wiley‐Liss, Inc.