Sage Journals: Discover world-class research

Abstract

The influence of lipopolysaccharide (LPS) and the nitric oxide synthase (iNOS) inhibitor-N-nitro-L-arginine on the formation of N-nitrosodimethylamine (NDMA) by HepG2 cells, engineered to overexpress CYP2E1, was assessed and compared with data from empty vector-transfected cells. HepG2 cells produced significant amounts of NDMA but its levels in the culture media of cells overexpressing CYP2E1 was significantly lower than in empty-vector transfected cells. LPS increased the formation of NDMA, the expression of the iNOS and the production of the nitric oxide (NO). On the other hand, L-NAME significantly decreased NDMA levels. The results above indicate that the synthesis of NDMA by HepG2 cells depends on NO production. Furthermore, ethanol did not affect iNOS expression but decreased NDMA levels in CYP2E1-transfected cells below the detection limit. It is probably caused by the increased N-nitrosodimethylamine metabolism. In conclusion, HepG2 cells' ability to synthesize NO with simultaneous CYP2E1 activation may lead to an increase of carcinogenic products of the NDMA metabolism.

Keywords

CYP2E1 ethanol HepG2 cells N-nitrosodimethylamine nitric oxide

References

1 Anderson LM , Chhabra SK , Nerurkar PV , Souliotis VL , Kyrtopoulos SA. Alcohol-related cancer risk: a toxicokinetic hypothesis . Alcohol 1995; 12: 97–104 .

2 Goldman R , Shields P . Food mutagens. J Nutr 2003; 133: 965–973 .

3 Cederbaum AI , Defeng W , Montserrat M , Jingxiang B . CYP2E1-dependent toxicity and oxidative stress in HepG2 cells . Free Radic Biol Med 2001; 31: 1539–1543 .

4 Loguericio C , Federico A . Oxidative stress in viral and alcoholic hepatitis . Free Radic Biol Med 2003; 34: 1–10 .

5 Balenko NV , Chernichenko IA , Yanysheva NY , Litvichenko ON , Sovertkova LS , Babii VF . The role of nitrogen dioxide in endogenous synthesis of carcinogenic nitrosamines . Exp Oncol 1997; 19: 20–25 .

6 Burney S , Caulfield JL , Niles JC , Wishnok JS , Tannenbaum SR . The chemistry of DNA damage from nitric oxide and peroxynitrite . Mutat Res 1999; 424: 37–49 .

7 Liu RH , Jacob JR , Hotchkiss JH , Tennant BC . Synthesis of nitric oxide and nitrosamine by immortalized woodchuck hepatocytes . Carcinogenesis 1993; 14: 1609–1613 .

8 Tamir S , Tannenbaum SR . The role of nitric oxide (NO) in the carcinogenic process . Biochem Biophys Acta 1996; 1288: 31–36 .

9 Wink DA , Mitchell JB . Nitric oxide and cancer: an introduction . Free Radic Biol Med 2003; 34: 951–954 .

10.

10 Robbins RA , Grisham MB . Nitric oxide . Int J Biochem Cell Biol 1997; 29: 857–860 .

11.

11 Ohsawa K , Nakagawa S , Kimura M , Shimada C , Tsuda S , Kabasawa K , Kawaguchi S , Sasaki YF . Detection of in vivo genotoxicity of endogenously formed N-nitroso compounds and suppression by ascorbic acid, teas and fruit juices . Mutat Res 2003; 539: 65–76 .

12.

12 Smith JL , Wishnok JS , Deen WM . Metabolism and excretion of methylamines in rats . Toxicol Appl Pharmacol 1994; 125: 296–308 .

13.

13 Vermeer ITM , Moonen EJC , Dallinga JW , Kleinjans JCS , van Maanen JMS . Effect of ascorbic acid and green tea on endogenous formation of N-nitrosodimethylamine and N-nitrosopiperydine in humans . Mutat Res 1999; 428: 353–361 .

14.

14 Leao MBC , Pavao AC . An electron transfer mechanism for the dimethylnitrosamine carcinogenic action . J Mol Structure 2001; 539: 279–301 .

15.

15 Thomas PE , Bandiera S , Maines SL , Ryan DE , Lewis W . Regulation of cytochrome p-450j, a high-affinity N-nitrosodimethylamine demethylase in rat hepatic microsomes . Biochemistry 1990; 26: 2280–2289 .

16.

16 Yamazaki H , Inui Y , Yun CH , Guengerich FP , Shimada T . Cytochrome p-450 2E1 and 2A6 enzymes as major catalysts for metabolic activation of N-nitrosodialkylamines and tobacco-related nitrosamines in human liver microsomes . Carcinogenesis 1992; 13: 1789–1794 .

17.

17 Souliotis VL , van Delft JH , Steenwinkel MJ , Baan RA , Kyrtopoulos SA . DNA adducts, mutant frequencies and mutation spectra in lambda lacZ transgenic mice treated with N-nitrosodimethylamine . Carcinogenesis 1998; 19: 731–739 .

18.

18 Williams GM , Iatropoulos MJ , Weisburger JH . Chemical carcinogen mechanisms of action and implications for testing methodology . Exp Toxicol 1996; 48: 101–111 .

19.

19 Lee JK , Choi SS , Won JS , Suh HW . The regulation of inducible nitric oxide synthase gene expression induced by lipopolysaccharide and tumor necrosis factor-a in C6 cells: involvement of AP-1 and NFkB . Life Sci 2003; 73: 595–609 .

20.

20 Dupont I , Bodenez P , Berthou F , Simon B , Bardou LG , Lucas D . Cytochrome P-450 2E1 activity and oxidative stress in alcoholic patients . Alcohol Alcoholism 2000; 35: 98–103 .

21.

21 Hakkak R , Korourian S , Ronis MJ , Ingelman-Sundberg M , Badger TM . Effects of diet and ethanol on the expression and localization of cytochromes P450 2E1 and P450 2C7 in the colon of male rats . Biochem Pharmacol 1995; 51: 61–69 .

22.

22 Goasduff T , Bellec G , Amet Y , Dreano Y , Menez JF , Berthou F . P-4502E1 expression in liver, kidney, and lung of rats treated with single or combined inducers . Alcohol 1996; 13: 301–308 .

23.

23 Schrammel A , Gorren ACF , Schmidt K , Pfeiffer S , Mayer B . S-nitrosation of glutathione by nitric oxide, peroxynitrite, and NO/O2 . Free Radic Biol Med 2003; 34: 1078–1088 .

24.

24 Longnecker MP . Alcohol consumption and risk of cancer in humans: an overview . Alcohol 1995; 12: 87–96 .

25.

25 Longnecker MP , Enger SM . Epidemiologic data on alcoholic beverage consumption and risk of cancer . Clin Chim Acta 1996; 246: 121–141 .

26.

26 Wang XD . Retinoids and alcohol-related carcinogenesis . J Nutr 2003; 133: 287–300 .

27.

27 Kukielka E , Cederbaum AI . The effect of chronic ethanol consumption on NAD-and NADPH-dependent generation of reactive oxygen intermediates by isolated rat liver nuclei . Alcohol Alcoholism 1992; 27: 233–239 .

28.

28 Hiramoto K , Ryuno Y , Kikugawa K . Decomposition of N-nitrosamines, and concomitant release of nitric oxide by Fenton reagent under physiological conditions . Mutat Res 2002; 520: 103–111 .

The effect of ethanol and nitric oxide on the N-nitrosodimethylamine formation in HepG2 cells overexpressing CYP2E1

Abstract

Keywords

References