Effects of diet and ethanol on the expression and localization of cytochromes P450 2E1 and P450 2C7 in the colon of male rats

doi:10.1016/0006-2952(95)02154-X

Biochemical Pharmacology

Volume 51, Issue 1, 12 January 1996, Pages 61-69

https://doi.org/10.1016/0006-2952(95)02154-X Get rights and content

Abstract

Local activation of procarcinogens in target tissues such as the colon by cytochrome P450-dependent microsomal monooxygenases is considered to be an important factor in the etiology of cancer. Diet and alcohol consumption are considered risk factors in colon cancer, and the cytochrome P450 isozymes CYP2E1 and CYP2C7 have been implicated in the biochemical mechanisms underlying colon cancer. The current study was conducted to determine the effects of diet and ethanol consumption on colonic and hepatic expression of these two enzymes. Adult male rat Sprague-Dawley rats were fed rat chow ad lib. or were infused intragastrically with control or ethanol-containing diets. Our results indicate that CYP2E1 is present in colonic epithelial cells, and expression of colonic and hepatic microsomal CYP2E1 and CYP2C7 was increased by chronic ethanol intake. As compared with rats having ad lib. access to standard rat food, rats receiving total enteral nutrition had significant (P < 0.01) reductions of CYP2C7 and slight, but not statistically significant, reductions in the expression of CYP2E1 in colon. Diet and ethanol differentially regulated CYP2E1 and CYP2C7 in a tissue-specific manner such that ethanol induced CYP2E1 and CYP2C7 in the colon and liver, and the intragastric diet alone had a tendency to induce these isozymes in the liver and reduce them in the colon. These results may provide a partial explanation for the mechanisms underlying effects of diet and ethanol on colon cancer.

References (48)

CS Lieber et al.
Hepatic microsomal ethanol-oxidizing system. In vitro characteristics and adaptive properties in vivo
J Biol Chem
(1970)
CS Yang et al.
Induction, purification, and characterization of cytochrome P450IIE
Methods Enzymol
(1991)
M Shimizu et al.
Immunohistochemical localization of ethanol-inducible P450IIE1 in the rat alimentary tract
Gastroenterology
(1990)
MA Leo et al.
New pathway for retinol metabolism in liver microsomes
J Biol Chem
(1985)
MA Leo et al.
Retinoic acid metabolism by a system reconstituted with cytochrome P-450
Arch Biochem Biophys
(1984)
S Bandiera et al.
Age- and sex-related expression of cytochromes P450f and P450g in rat liver
Arch Biochem Biophys
(1986)
R Hakkak et al.
Effects of enteral nutrition and ethanol on cytochrome P450 distribution in small intestine of male rats
Gastroenterology
(1993)
MA Leo et al.
Interaction of drugs and retinol
Biochem Pharmacol
(1986)
TM Badger et al.
Pulsatile blood alcohol and CYP2E1 induction during chronic alcohol infusions in rats
Alcohol
(1993)
FP Guengerich

DW Nebert et al.

The P450 superfamily: Update on new sequences, gene mapping and recommended nomenclature

DNA Cell Biol

(1991)

FP Guengerich

Roles of cytochrome P450 enzymes in chemical carcinogenesis and cancer chemotherapy

Cancer Res

(1988)

AH Conney

Induction of microsomal enzymes by foreign chemicals and carcinogenesis by polycyclic aromatic hydrocarbons

E Bjelke

Epidemiological Studies of Cancer of the Stomach, Colon and Rectum

EL Wynder et al.

Environmental factors of cancer of the colon and rectum

Cancer

(1967)

I Kato et al.

A case-control study of male colorectal cancer in Aichi Prefecture, Japan: With special reference to occupational activity level, drinking habits and family history

Jpn J Cancer Res

(1990)

S Kune et al.

Case-control study of alcoholic beverages as etiological factors: The Melborne colorectal cancer study

Nutr Cancer

(1987)

JE Enstrom

Colorectal cancer and beer drinking

Br J Cancer

(1977)

ES Pollack et al.

Prospective study of alcohol consumption and cancer

N Engl J Med

(1984)

HK Seitz et al.

Enhancement of 1,2-dimethylhydrazine-induced retal carcinogenesis following chronic ethanol consumption in the rat

Gastroenterology

(1984)

SR Hamilton et al.

Effects of chronic dietary beer and ethanol consumption on experimental colonic carcinogenesis by azoxymethane in rats

Cancer Res

(1987)

FT Garzon et al.

Enhancement of acetoxymethylmethylnitrosamine (AMMN)-induced colorectal tumors following chronic ethanol consumption in rats

Gasteroenterology

(1986)

E Rubin et al.

Hepatic microsomal enzymes in man and rat, induction and inhibition by ethanol

Science

(1968)

JR Gillette

Environmental factors in drug metabolism

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The liver is a unique organ in the body as it has significant roles in both metabolism and innate immune clearance. Hepatocytes in the liver carry a nearly complete complement of drug metabolizing enzymes, including numerous cytochrome P450s. While a majority of these enzymes effectively detoxify xenobiotics, or metabolize endobiotics, a subportion of these reactions result in accumulation of metabolites that can cause either direct liver injury or indirect liver injury through activation of inflammation. The liver also contains multiple populations of innate immune cells including the resident macrophages (Kupffer cells), a relatively large number of natural killer cells, and blood-derived neutrophils. While these cells are primarily responsible for clearance of pathogens, activation of these immune cells can result in significant tissue injury during periods of inflammation. When activated chronically, these inflammatory bouts can lead to fibrosis, cirrhosis, cancer, or death. This chapter will focus on interactions between how the liver processes xenobiotic and endobiotic compounds through the cytochrome P450 system, and how these processes can result in a response from the innate immune cells of the liver. A number of different clinically relevant diseases, as well as experimental models, are currently available to study mechanisms related to the interplay of innate immunity and cytochrome P450-mediated metabolism. A major focus of the chapter will be to evaluate currently understood mechanisms in the context of these diseases, as a way of outlining mechanisms that dictate the interactions between the P450 system and innate immunity.
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Citation Excerpt :
Alcohol metabolism by Cyp2e1 may be contributing to alcohol-induced effects on the intestine. It is well-established that: (1) Cyp2e1 is expressed in Caco-2 cells as well as in both the small intestine and colon tissue in rodents and humans [36–38]; (2) Cyp2e1 protein is induced in intestinal tissue by chronic alcohol feeding in rodents and humans[36,37,39,40] mainly through post-translational mechanisms rather than mRNA expression [41]; (3) Cyp2e1 is one of the most highly expressed of the CYP450 isoforms in the human intestine [38,42]; and (4) Cyp2e1 metabolism of alcohol produces oxidative stress products [24,36,43] that can contribute to alcohol-induced tissue damage including reactive oxygen species/reactive nitrogen species (ROS/RNS) that could mediate disruption of intestinal epithelial permeability directly [23,26–28]. Oxidative stress also promotes cell signaling, cellular damage, and changes to proteins regulating permeability including tight junction proteins [23,27,28].
Chronic alcohol use can result in many pathological effects including alcoholic liver disease (ALD). While alcohol is necessary for the development of ALD, only 20–30% of alcoholics develop alcoholic steatohepatitis (ASH) with progressive liver disease leading to cirrhosis and liver failure (ALD). This suggests that while chronic alcohol consumption is necessary it is not sufficient to induce clinically relevant liver damage in the absence of a secondary risk factor. Studies in rodent models and alcoholic patients show that increased intestinal permeability to microbial products like endotoxin play a critical role in promoting liver inflammation in ALD pathogenesis. Therefore identifying mechanisms of alcohol-induced intestinal permeability is important in identifying mechanisms of ALD and for designing new avenues for therapy. Cyp2e1 is a cytochrome P450 enzyme that metabolizes alcohol has been shown to be upregulated by chronic alcohol use and to be a major source of oxidative stress and liver injury in alcoholics and in animal and in vitro models of chronic alcohol use. Because Cyp2e1 is also expressed in the intestine and is upregulated by chronic alcohol use, we hypothesized it could play a role in alcohol-induced intestinal hyperpermeability. Our in vitro studies with intestinal Caco-2 cells and in mice fed alcohol showed that circadian clock proteins CLOCK and PER2 are required for alcohol-induced permeability. We also showed that alcohol increases Cyp2e1 protein and activity but not mRNA in Caco-2 cells and that an inhibitor of oxidative stress or siRNA knockdown of Cyp2e1 prevents the increase in CLOCK or PER2 proteins and prevents alcohol-induced hyperpermeability. With our collaborators we have also shown that Cyp2e1 knockout mice are resistant to alcohol-induced gut leakiness and liver inflammation. Taken together our data support a novel Cyp2e1-circadian clock protein mechanism for alcohol-induced gut leakiness that could provide new avenues for therapy of ALD.
Expression of selected cytochrome P450 isoforms and of cooperating enzymes in colorectal tissues in selected pathological conditions
2014, Pathology Research and Practice
Citation Excerpt :
CYP2E1 is one of two forms of CYP, which in our studies manifested a much lower expression in the small intestine than in liver. This is consistent with an earlier report in which CYP2E1 showed high expression in the perivenous part of the liver lobule and only low concentrations in the small intestine [40]. Other reports related to intestinal expression of CYP2E1 are contradictory.
The current interest in CYP expression in the colon results from its uniqueness as a target organ for cancer.
To date, the CYP expression profiles in the colon have not yet been subject of comprehensive research. In this study, we investigated 40 patients with Crohn's disease, 40 with ulcerative colitis, and 40 healthy subjects as a control group. Colon tissues were fixed, dehydrated, cleared in xylene and embedded in paraffin. Sections were prepared from paraffin blocks for immunohistochemical staining with specific antibodies. We used antibodies to the human CYP1A1, CYP2B6, CYP2C9, CYP2E1 and CYP3A4 isoforms, as well as antibodies to the human glycoprotein P, glutathione-S transferase and antibody to the UDP-glucuronosyltransferase. The sections were stained immunohistochemically and examined using light microscopy. Cellular localization was determined, and computer image analysis was used.
In all cases with Crohn's disease, the proteins studied showed at least a twofold expression. Ulcerative colitis showed a much weaker influence regarding the expression of the proteins studied but in case of CYP2C9 and UDP-glucuronosyltransferase, a decrease of expression was observed.
CYP2E1 potentiates binge alcohol-induced gut leakiness, steatohepatitis, and apoptosis
2013, Free Radical Biology and Medicine
Citation Excerpt :
However, our results simply indicate greater elevation of iNOS and 3-NT levels in the WT-EtOH than in the corresponding Cyp2e1-null mice. Taken together, intestinal CYP2E1, induced by alcohol exposure possibly through protein stabilization [36,39,40], plays a central role in promoting binge alcohol-induced nitroxidative stress, gut leakiness, and bacterial translocation, contributing to elevated levels of serum endotoxin and hepatic cytokines, which prime the liver to more severe injury through oxidative stress-mediated events [11,30,31]. Increased hepatic cytokine levels were also implicated in the development of hepatic steatosis, as recently reported in an acute binge ethanol model [41].
Ethanol-inducible cytochrome P450 2E1 (CYP2E1) contributes to increased oxidative stress and steatosis in chronic alcohol-exposure models. However, its role in binge ethanol-induced gut leakiness and hepatic injury is unclear. This study was aimed at investigating the role of CYP2E1 in binge alcohol-induced gut leakiness and the mechanisms of steatohepatitis. Female wild-type (WT) and Cyp2e1-null mice were treated with three doses of binge ethanol (WT-EtOH or Cyp2e1-null–EtOH) (6 g/kg oral gavage at 12-h intervals) or dextrose (negative control). Intestinal histology of only WT-EtOH exhibited epithelial alteration and blebbing of lamina propria, and liver histology obtained at 6 h after the last ethanol dose showed elevated steatosis with scattered inflammatory foci. These were accompanied by increased levels of serum endotoxin, hepatic enterobacteria, and triglycerides. All these changes, including the intestinal histology and hepatic apoptosis, determined by TUNEL assay, were significantly reversed when WT-EtOH mice were treated with the specific inhibitor of CYP2E1 chlormethiazole and the antioxidant N-acetylcysteine, both of which suppressed oxidative markers including intestinal CYP2E1. WT-EtOH also exhibited elevated amounts of serum TNF-α, hepatic cytokines, CYP2E1, and lipid peroxidation, with decreased levels of mitochondrial superoxide dismutase and suppressed aldehyde dehydrogenase 2 activity. Increased hepatocyte apoptosis with elevated levels of proapoptotic proteins and decreased levels of active (phosphorylated) p-AKT, p-AMPK, and peroxisome proliferator-activated receptor-α, all of which are involved in fat metabolism and inflammation, were observed in WT-EtOH. These changes were significantly attenuated in the corresponding Cyp2e1-null–EtOH mice. These data indicate that both intestinal and hepatic CYP2E1 induced by binge alcohol seems critical in binge alcohol-mediated increased nitroxidative stress, gut leakage, and endotoxemia; altered fat metabolism; and inflammation contributing to hepatic apoptosis and steatohepatitis.
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View all citing articles on Scopus

^☆: This work was supported, in part, by NIAAA R01088645(T.M.B).

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Research paperEffects of diet and ethanol on the expression and localization of cytochromes P450 2E1 and P450 2C7 in the colon of male rats☆

Abstract

J Biol Chem

Methods Enzymol

Gastroenterology

J Biol Chem

Arch Biochem Biophys

Arch Biochem Biophys

Gastroenterology

Biochem Pharmacol

Alcohol

The P450 superfamily: Update on new sequences, gene mapping and recommended nomenclature

DNA Cell Biol

Roles of cytochrome P450 enzymes in chemical carcinogenesis and cancer chemotherapy

Cancer Res

Induction of microsomal enzymes by foreign chemicals and carcinogenesis by polycyclic aromatic hydrocarbons

Epidemiological Studies of Cancer of the Stomach, Colon and Rectum

Environmental factors of cancer of the colon and rectum

Cancer

A case-control study of male colorectal cancer in Aichi Prefecture, Japan: With special reference to occupational activity level, drinking habits and family history

Jpn J Cancer Res

Case-control study of alcoholic beverages as etiological factors: The Melborne colorectal cancer study

Nutr Cancer

Colorectal cancer and beer drinking

Br J Cancer

Prospective study of alcohol consumption and cancer

N Engl J Med

Enhancement of 1,2-dimethylhydrazine-induced retal carcinogenesis following chronic ethanol consumption in the rat

Gastroenterology

Effects of chronic dietary beer and ethanol consumption on experimental colonic carcinogenesis by azoxymethane in rats

Cancer Res

Enhancement of acetoxymethylmethylnitrosamine (AMMN)-induced colorectal tumors following chronic ethanol consumption in rats

Gasteroenterology

Hepatic microsomal enzymes in man and rat, induction and inhibition by ethanol

Science

Environmental factors in drug metabolism

Research paper
Effects of diet and ethanol on the expression and localization of cytochromes P450 2E1 and P450 2C7 in the colon of male rats☆