DISSECTING COX-1 RELATED GENE PATHWAYS IN OVARIAN CANCER

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. ABSTRACT Ovarian cancer is the leading cause of death among gynecologic cancers in the United States. The prostaglandin (PG) pathway mediated by cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) enzymes is implicated in ovulation and has been suggested as a potential factor in the etiology of ovarian cancer. Preliminary Data: We have utilized cDNA microarrays to compare normal ovarian tissue samples to ovarian carcinomas, and through this process have shown expression levels of COX-1 to be more than 2-fold higher in the cancers. Data published by our collaborators similarly demonstrates that COX-1, not COX-2, is highly expressed in ovarian malignancies. Hypothesis and Aims: The long-range goal of this research is to determine the specific contributions of COX-1 to ovarian carcinogenesis. We hypothesize that in ovarian cancers, COX-1 induces PGE2 production, which targets phosphatidylinositol 3 kinase/protein kinase B (PI3K/AKT) signaling and components of this pathway that are involved in tumor growth and progression. We propose the use of custom-made tissue arrays for immunohistochemistry (IHC) staining to measure expression levels of COX-1, COX-2 and molecular markers associated with PI3K: phosphorylated AKT (pAKT), hypoxia induced factor (HIF-1¿) and vascular endothelial growth factor (VEGF). Parallel in vitro experiments will be performed to further evaluate COX-1 function by treating a COX-1 expressing cell line, OVCAR3, with a selective COX-1 inhibitor, SC-560. We will measure PGE2 metabolism, cell growth, apoptosis, migration and invasion, as well as expression levels of PI3K, pAKT, HIF-1¿ and VEGF. We will also utilize cDNA microarrays to generate gene profiles that are associated with COX-1. Significance: If we determine that COX-1 is indeed a prominent factor in tumor progression in ovarian cancer, this research may provide the basis for its future use as a biomarker and target for therapy in the management of this deadly disease.