Carnosic Acid Induces the NAD(P)H: Quinone Oxidoreductase 1 Expression in Rat Clone 9 Cells through the p38/Nuclear Factor Erythroid-2 Related Factor 2 Pathway

Abstract

The anticarcinogenic effect of rosemary has been partly attributed to the modulation of the activity and expression of phase II detoxification enzymes. Here we compared the effects of phenolic diterpenes from rosemary on the expression of NAD(P)H: quinone oxidoreductase 1 (NQO1) in rat Clone 9 liver cells. Cells were treated with 1-20 μmol/L of carnosic acid (CA) or carnosol (CS) for 24 h. Both CA and CS dose dependently increased NQO1 enzyme activity and protein expression, and the induction potency of CA was stronger than that of CS. The increase in NQO1 enzyme activity in cells treated with 10 μmol/L CA and CS was 4.1- and 1.9-fold, respectively (P < 0.05). RT-PCR showed that CA and CS induced NQO1 mRNA in a dose-dependent manner. Furthermore, CA dose dependently induced transcription of nuclear factor erythroid-2 related factor 2 (Nrf2) and antioxidant response element (ARE)-luciferase reporter activity. Silencing of Nrf2 expression alleviated NQO1 protein expression and ARE-luciferase activity by CA. Moreover, the phosphorylation of p38 was mainly stimulated in the presence of CA. Pretreatment with SB203580 or silencing of p38 expression inhibited Nrf2 activation and NQO1 induction. These results suggest that the increased NQO1 expression by CA is likely related to the p38-Nrf2 pathway and help to clarify the possible molecular mechanism of action of rosemary phenolic compounds in drug metabolism and cancer prevention.

Dual regulation of transcription factor Nrf2 by Keap1 and by the combined actions of β-TrCP and GSK-3

“…In the above studies, the use of kinase inhibitors and dominant-negative mutants to blunt gene induction suggest that ERK and JNK positively regulate Nrf2 activity. In marked contrast, p38 MAPK has been reported to both positively and negatively regulate Nrf2 [84,[91][92][93][94] and this may reflect cell-specific differences in p38 MAPK signalling pathways or response to chemicals.…”

A Versatile ΦC31 Based Reporter System for Measuring AP-1 and Nrf2 Signaling in Drosophila and in Tissue Culture

“…For example, Tsai et al [40] used a mammalian reporter that contains an ARE-driven luciferase gene. However, this construct also contains nucleotides that confer JNK specificity.…”

Anticancer Effects of Rosemary (Rosmarinus officinalis L.) Extract and Rosemary Extract Polyphenols

“…Rat liver clone 9 cells are often used as a model for screening hepatotoxicity and CA was found to enhance activity of enhancer element GPEI which regulates the pi class of glutathione S -transferase and modulates antioxidant and detoxification systems within the cell [60]. CA was found to exert a protective effect in these non-cancerous liver cells which was modulated by the Nrf2/p38 MAPK signaling pathway [60,61]. Furthermore, CA inhibited viability of small-cell lung cancer NCI-H82 cells [30].…”