Abstract LB-160: CYP4F isoform expression and 20-HETE synthesis in prostate cancer cells are regulated by androgen and contribute to growth

Abstract

Abstract 20-hydroxyeicosatetraenoic acid (20-HETE), a CYP450-derived arachidonic acid metabolite in the microcirculation, contributes to vascular tone and stimulates vascular and epithelial cell proliferation, angiogenesis and inflammation, all of which play a role in cancer progression. Our laboratory identified 20-HETE as the mediator of androgen-induced hypertension. Given that androgen contributes to the pathogenesis of prostate cancer, we examined the presence and function of 20-HETE in human prostate cancer cells. Androgen-responsive prostate cancer cells, LNCaP, produced 2-fold more 20-HETE compared to androgen-nonresponsive C4-2 cells (565±139 pg/mg protein vs 223±50 pg/mg protein). Both C4-2 and LNCaP produced greater amount of 20-HETE compared with U87 glioma, MCF-7 breast cancer and ML-1 thyroid cancer cells. 20-HETE levels in prostate primary stromal cells and epithelial RWPE-1 cells were barely detected (16±26 and 23±40 pg/mg protein respectively). Treatment of LNCaP with 5 alpha-dihydrotestosterone (DHT) stimulated 20-HETE production by 65% when compared to vehicle control. DHT treatment did not alter 20-HETE levels in C4-2. Treatment of C4-2 and LNCaP with HET0016, an inhibitor of 20-HETE synthesis, selectively decreased endogenous 20-HETE production while inhibiting cell growth in a dose-dependent manner. Further addition of exogenous 20-HETE stimulated growth. CYP4F2, CYP4F3 and CYP4F8 mRNA levels were several fold higher in LNCaP compared with C4-2, while levels of CYP4A11 and CYP4A22 mRNA were unchanged. In LNCaP, DHT increased CYP4F isoform expression without altering the CYP4A expression; flutamide abrogated DHT-induced expression of CYP4F2 and CYP4F3 but did not affect expression of CYP4F8. Importantly, flutamide inhibited DHT-stimulated 20-HETE production. These results suggest that 20-HETE has an important role in cancer cell proliferation and CYP4F2/3 might be the source of androgen-driven 20-HETE synthesis via androgen receptor dependent pathway. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-160. doi:1538-7445.AM2012-LB-160