H. Biri et al., Activities of DNA turnover and free radical metabolizing enzymes in cancerous human prostate tissue, CANCER INV, 17(5), 1999, pp. 314-319
Activities of adenosine deaminase (ADA), 5'nucleotidase (5'NT), xanthine ox
idase (XO), superoxide dismutase (SOD), glutathione pel oxidase (GSH-Px), a
nd catalase (CAT) and levels of thiobarbituric acid reagent substances (TBA
RS) were measured in 10 cancerous and 10 noncancerous human prostate tissue
s. Decreased activities of DNA turnover enzymes (ADA and 5'NT), increased a
ctivities of GSH-Px and CAT, and unchanged activities of SOD and XO were ob
served in cancerous prostate tissues compared with those of noncancerous on
es. TEARS levels were found to be higher in cancerous tissues than noncance
rous ones. In correlation analysis, mostly positive correlations were estab
lished between enzyme activities of the cancerous tissues, whereas no meani
ngful correlations were found between enzyme activities of the noncancerous
tissues except for a positive correlation between XO and SOD. The results
indicate that the activities of DNA turnover enzymes were reduced, which wa
s possibly an attempt to lower the rate of purine catabolism, and the activ
ities of GSH-Px a,td CAT enzymes were increased, probably in response to in
creased free radical stress occurring in cancerous prostate tissues. Increa
sed concentrations of TEARS suggested oxidant stress and thus accelerated p
er oxidative reactions in the cancerous tissues, even though antioxidant de
fense mechanisms were e activated These findings suggest that enzymatic ant
ioxidant systems of cancerous prostate tissues cannot sufficiently eliminat
e oxidant factors and prevent cellular peroxidative reactions occurring dur
ing the carcinogenic process.