Abstract 78: Role of 12-lipoxygenase in regulation of ovarian cancer cell proliferation and survival

Abstract

Abstract Enzymes involved in eicosanoid synthesis have previously been implicated in the progression of various types of cancer, including ovarian carcinomas. Most of the current data in ovarian cancer have focused on cyclooxygenase-2 (COX-2). It is not known whether the main human 12-hydroxyeicosatetrenoate (12-HETE) generating enzyme, 12-lipoxygenase (12-LOX), contributes to the regulation of growth of ovarian cancer cells. In the present study, we examined the function of the 12-lipoxygenase pathway in the regulation of proliferation and survival of three epithelial ovarian cancer (EOC) cell lines. We found that all three EOC cells express high level of the mRNA encoding for 12-LOX, using RT-PCR. These cells also contain significant amount of immuno-reactive 12-LOX protein as revealed by western blot. Liquid chromatography/Mass Spectrometry (LC/MS) analysis confirmed that all three EOC produce 12-HETE when challenged with arachidonic acid (AA). N-benzyl-n-hydroxy-5-phenyl-pentanamide (BMD-122) is a specific 12-LOX inhibitor. Exposure of the three EOC cell lines to an increasing dose of the 12-LOX inhibitor, BMD-122 (1 μM, 10 μM and 50 μM), resulted in a dose-dependent inhibition in cell proliferation (75±9%, 51±6% and 26±4% of untreated control, respectively), measured by MTT assay in vitro. Furthermore, treatment with 10 μM BMD-122 was associated with up to ∼30% increases in the apoptosis of these EOC cells within 24 hr, measured by Annexin-V flow cytometry. This apoptosis seems to be mediated through a mechanism independent of PI-3 kinase since the expression of phosphorylated Akt was not affected by BMD-122 treatment. Furthermore, we found that BMD-122 treatment had no effect on the three EOC cell lines ability to invasion using Matrigel assay. Taken together, these data suggest that 12-LOX is involved in regulation of ovarian cancer progression and survival, an important and novel finding. Inhibition of 12-LOX may have potential as an adjuvant therapy in ovarian cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 78.