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Biochemistry - Oncology - Urology

15-Lipoxygenase Metabolites of Docosahexaenoic Acid Inhibit Prostate Cancer Cell Proliferation and Survival
Published: Thursday, September 20, 2012
Author: Joseph T. O’Flaherty et al.

by Joseph T. O’Flaherty, Yungping Hu, Rhonda E. Wooten, David A. Horita, Michael P. Samuel, Michael J. Thomas, Haiguo Sun, Iris J. Edwards

A 15-LOX, it is proposed, suppresses the growth of prostate cancer in part by converting arachidonic, eicosatrienoic, and/or eicosapentaenoic acids to n-6 hydroxy metabolites. These metabolites inhibit the proliferation of PC3, LNCaP, and DU145 prostate cancer cells but only at =1–10 µM. We show here that the 15-LOX metabolites of docosahexaenoic acid (DHA), 17-hydroperoxy-, 17-hydroxy-, 10,17-dihydroxy-, and 7,17-dihydroxy-DHA inhibit the proliferation of these cells at =0.001, 0.01, 1, and 1 µM, respectively. By comparison, the corresponding 15-hydroperoxy, 15-hydroxy, 8,15-dihydroxy, and 5,15-dihydroxy metabolites of arachidonic acid as well as DHA itself require =10–100 µM to do this. Like DHA, the DHA metabolites a) induce PC3 cells to activate a peroxisome proliferator-activated receptor-? (PPAR?) reporter, express syndecan-1, and become apoptotic and b) are blocked from slowing cell proliferation by pharmacological inhibition or knockdown of PPAR? or syndecan-1. The DHA metabolites thus slow prostate cancer cell proliferation by engaging the PPAR?/syndecan-1 pathway of apoptosis and thereby may contribute to the prostate cancer-suppressing effects of not only 15-LOX but also dietary DHA.