Regulation of cytochrome P450 2e1 expression by ethanol: role of oxidative stress-mediated pkc/jnk/sp1 pathway

Abstract

CYP2E1 metabolizes ethanol leading to production of reactive oxygen species (ROS) and acetaldehyde, which are known to cause not only liver damage but also toxicity to other organs. However, the signaling pathways involved in CYP2E1 regulation by ethanol are not clear, especially in extra-hepatic cells. This study was designed to examine the role of CYP2E1 in ethanol-mediated oxidative stress and cytotoxicity, as well as signaling pathways by which ethanol regulates CYP2E1 in extra-hepatic cells. In this study, we used astrocytic and monocytic cell lines, because they are important cells in central nervous system . Our results showed that 100 mM ethanol significantly induced oxidative stress, apoptosis, and cell death at 24 h in the SVGA astrocytic cell line, which was rescued by a CYP2E1 selective inhibitor, diallyl sulfide (DAS), CYP2E1 siRNA, and antioxidants (vitamins C and E). Further, we showed that DAS and vitamin C abrogated ethanol-mediated (50 mℳ) induction of CYP2E1 at 6 h, as well as production of ROS at 2 h, suggesting the role of oxidative stress in ethanol-mediated induction of CYP2E1. We then investigated the role of the protein kinase C/c-Jun N-terminal kinase/specificity protein1 (PKC/JNK/SP1) pathway in oxidative stress-mediated CYP2E1 induction. Our results showed that staurosporine, a non-specific inhibitor of PKC, as well as specific PKCζ inhibitor and PKCζ siRNA, abolished ethanol-induced CYP2E1 expression. In addition, inhibitors of JNK (SP600125) and SP1 (mithramycin A) completely abrogated induction of CYP2E1 by ethanol in SVGA astrocytes. Subsequently, we showed that CYP2E1 is also responsible for ethanol-mediated oxidative stress and apoptotic cell death in U937 monocytic cell lines. Finally, our results showed that PKC/JNK/SP1 pathway is also involved in regulation of CYP2E1 in U937 cells. This study has clinical implications with respect to alcohol-associated neuroinflammatory toxicity among alcohol users.

Oxidative stress and breast cancer biomarkers: the case of the cytochrome P450 2E1

“…[40][41][42][43] Studies in our and other laboratories have indicated diverse levels of CYP2E1 gene expression in a manner dependent on the genetic background and the migratory potential of these cells. [16,17,29,34] CYP2E1 overexpression in breast cancer cells is involved in the alteration of numerous pathways linked to the disease such as cell cycle control, apoptosis, autophagy, ER stress and UPR.…”

Expression of PUMA in Follicular Granulosa Cells Regulated by FoxO1 Activation During Oxidative Stress

“…[32][33][34][35] Once JNK is activated, it functions to increase expression of downstream transcription factors, like SP1, p53, and FoxO1. 36,37 It has been reported that JNK1-dependent PUMA expression can induce hepatocyte lipoapoptosis 38 as well as apoptosis of cisplatin-resistant ovarian cancer cells. 39 Notably, excess ROS not only increase FoxO expression, but also enhance expression of p53, 40 another known PUMA transcription factor.…”

Cell-Specific Effects of Ethanol on Nitric Oxide Synthase Induced by Inflammatory Mediators

“…Generation of reactive oxygen species (ROS) is presumed to be the key causative event in oxidative injury. Some investigators also showed that Soymida februfuga ethanol extract can protect against ethanol induced oxidative damage in HepG2 cells [14]. The effect of NO on oxidative stress in the liver appears complex since both pro-oxidant and antioxidant properties have been reported by various investigators.…”