Activities of antioxidant and redox enzymes in human normal hepatic and hepatoma cell lines.
The cellular defense system (including glutathione, glutathione-related enzymes, antioxidant and redox enzymes) plays a crucial role in cell survival and growth in aerobic organisms. To understand its physiological role in tumor cells, the glutathione content and related enzyme activities in the human normal hepatic cell line, Chang and human hepatoma cell line, HepG2, were systematically measured and compared. Superoxide dismutase, catalase, and glutathione peroxidase activities are 2.8-, 4.3-, and 2.9-fold higher in HepG2 cells than in Chang cells. Total glutathione content is also about 1.4-fold higher in HepG2, which is supported by significant increases in gamma-glutamylcysteine synthetase and glutathione synthetase activities. Two other glutathione-related enzymes, glutathione reductase and gamma-glutamyltranspeptidase, are upregulated in HepG2 cells. However, thioredoxin reductase and glutathione S-transferase activities are significantly lower in HepG2 cells. These results propose that defense-related enzymes are largely modulated in tumor cells, which might be linked to their growth and maintenance.
Lee
Yuk-Young
YY
Division of Life Sciences, Kangwon National University, Chunchon, Korea.
Kim
Hong-Gyum
HG
Jung
Haeng-Im
HI
Shin
Youn Hee
YH
Hong
Sung Min
SM
Park
Eun-Hee
EH
Sa
Jae-Hoon
JH
Lim
Chang-Jin
CJ
D000975:Antioxidants / Q000378:metabolism*; D006528:Carcinoma, Hepatocellular / Q000201:enzymology*; D002460:Cell Line; D054477:Glutaredoxins; D005978:Glutathione / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D008099:Liver / Q000201:enzymology*; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology; D010088:Oxidoreductases / Q000378:metabolism; D011490:Protein Disulfide Reductase (Glutathione); D017382:Reactive Oxygen Species / Q000378:metabolism
D000975:Antioxidants; D054477:Glutaredoxins; D017382:Reactive Oxygen Species; D010088:Oxidoreductases; D011490:Protein Disulfide Reductase (Glutathione); D005982:Glutathione Transferase; D005978:Glutathione