Nuclear factor E2-related factor 2-mediated induction of NAD(P)H:quinone oxidoreductase 1 by 3,5-dimethoxy-trans-stilbene.
ABSTRACT NAD(P)H:quinone oxidoreductase 1 (NQO1), a phase II enzyme, plays an important role in the detoxification or chemoprotection of carcinogens, and induction of this enzyme is a target for the prevention of carcinogenesis. Natural stilbenoids have potential cancer chemopreventive activities, potentially through affecting NQO1 activity. Along this line, several stilbenoids were evaluated to procure more potent compounds for inducing NQO1 activity in cultured murine Hepa 1c1c7 cells. As a result, we found that 3,5-dimethoxy-trans-stilbene (DMS) possesses potent NQO1 induction activity through up-regulation of both protein and mRNA expression of NQO1 as determined by Western blot and reverse transcription-polymerase chain reaction analysis, respectively. DMS also increased protein expression of heme oxygenase-1 (HO-1), another phase II enzyme. This induction of NQO1 and HO-1 by DMS was closely related to the regulation of nuclear factor E2-related factor 2 (Nrf2). The translocation and activation of Nrf2 by DMS was also involved in the modulation of the upstream signal transduction molecule, protein kinase C δ. These findings suggest that DMS might have a cancer chemopreventive activity by inducing detoxifying enzymes such as NQO1 and HO-1.
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ABSTRACT: Pinosylvin, a naturally occurring trans-stilbenoid mainly found in Pinus species, has exhibited a potential cancer chemopreventive activity. However, the growth inhibitory activity against cancer cells and the underlying molecular mechanisms remain to be elucidated. Therefore, the anti-proliferative activity of pinosylvin was investigated in human colorectal HCT 116 cancer cells. Pinosylvin inhibited the proliferation of HCT 116 cells by arresting transition of cell cycle from G1 to S phase along with the downregulation of cyclin D1, cyclin E, cyclin A, cyclin dependent kinase 2 (CDK2), CDK4, c-Myc, and retinoblastoma protein (pRb), and the upregulation of p21(WAF1/CIP1) and p53. Pinosylvin was also found to attenuate the activation of proteins involved in focal adhesion kinase (FAK)/c-Src/extracellular signal-regulated kinase (ERK) signaling, and phosphoinositide 3-kinase (PI3K)/Akt/ glycogen synthase kinase 3β (GSK-3β) signaling pathway. Subsequently, pinosylvin suppressed the nuclear translocation of β-catenin, one of downstream molecules of PI3K/Akt/GSK-3β signaling, and these events led to the sequential downregulation of β-catenin-mediated transcription of target genes including BMP4, ID2, survivin, cyclin D1, MMP7, and c-Myc. These findings demonstrate that the anti-proliferative activity of pinosylvin might be associated with the cell cycle arrest and downregulation of cell proliferation regulating signaling pathways in human colorectal cancer cells.Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association 01/2013; · 2.99 Impact Factor
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ABSTRACT: Thyroid hormone (T3 )-induced calorigenesis triggers the hepatic production of reactive oxygen species (ROS) and redox-sensitive nuclear transcription factor erythroid 2-related factor 2 (Nrf2) activation. The aim of this study was to test the hypothesis that in vivo T3 administration upregulates the expression of phase II and III detoxification proteins that is controlled by Nrf2. Male Sprague-Dawley rats were given a single intraperitoneal dose of 0.1 mg T3 /kg or T3 vehicle (controls). After treatment, rectal temperature of the animals, liver Nrf2 DNA binding (EMSA), protein levels of epoxide hydrolase 1 (Eh1), NADPH-quinone oxidoreductase 1 (NQO1), glutathione-S-transferases Ya (GST Ya) and Yp (GST Yp), and multidrug resistance-associated proteins 2 (MRP-2) and 4 (MRP-4) (Western blot), and MRP-3 (RT-PCR) were determined at different times. T3 significantly rose the rectal temperature of the animals in the time period studied, concomitantly with increases (P < 0.05) of liver Nrf2 DNA binding at 1 and 2 h after treatment, which was normalized at 4-12 h. Within 1-2 h after T3 treatment, liver phase II enzymes Eh1, NQO1, GST Ya, and GST Yp were enhanced (P < 0.05) as did phase III transporters MRP-2 and MRP-3, whereas MRP-4 remained unchanged. In conclusion, enhancement of liver Nrf2 DNA binding elicited by in vivo T3 administration is associated with upregulation of the expression of detoxification and drug transport proteins. These changes, in addition to antioxidant protein induction previously observed, may represent cytoprotective mechanisms underlying T3 preconditioning against liver injury mediated by ROS and chemical toxicity. © 2013 BioFactors, 2013.BioFactors 03/2013; · 3.09 Impact Factor