INCREASED PHOSPHOLIPID FATTY-ACID REMODELING IN HUMAN AND RAT PROSTATIC ADENOCARCINOMA TISSUES

Purpose: To study the mechanism of diminished arachidonic acid levels in malignant prostatic tissues. Materials and Methods: Benign and mali gnant prostate tissues were obtained from human radical prostatectomy specimens and from rats using Pollard's Lobund/Wistar rat prostate can cer model. Fatty acid composition and a variety of enzyme activities i nvolved in maintaining phospholipid fatty acid composition were compar ed in malignant and benign prostatic tissues. Results: Decreased arach idonic acid levels, previously reported in human prostate cancer, were present in malignant rat as well as in human tissues. There were 21% and 26% decreases of arachidonic acid levels in the rat and human mali gnant tissues compared with benign tissues. Fatty acid desaturase acti vity was undetectable. Fatty acyl-CoA hydrolase and synthetase activit ies were not altered in the malignant tissues. However, there was a 2- fold increase in phospholipase A(2) activity and a 4- to 12-fold incre ase in fatty acyl-CoA lysophosphatidylcholine acyltransferase activity in malignant rat and human prostatic tissues. Conclusions: These data indicate that, in malignant prostate tissues, the fatty acid remodeli ng mechanism is activated through the deacylation-reacylation cycle. T his process may be a result of increased use of arachidonic acid for t he formation of prostaglandins that may be crucial for the further dev elopment and growth of the malignant tissues.