Abstract A005: Identification of lipid pharmacodynamic biomarkers in FAP model


 Familial Adenomatous Polyposis (FAP) is a genetic disorder characterized by the development of numerous polyps in the colon, that unless removed by colectomy, inevitably progress to colorectal cancer (CRC). Although there is currently no FDA-approved treatment to delay colectomy, a common target for chemoprevention is cyclooxygenase-2 (COX-2). Non-steroidal anti-inflammatory drugs (NSAIDs) and omega-3 fatty acids are known to alter COX metabolism and affect downstream eicosanoids involved in CRC progression. In this study, we examined the chemopreventive efficacy of the NSAID naproxen alone, or in combination with TP-252, a novel, chemically-stable analogue of the omega-3 fatty acid, eicosapentaenoic acid (EPA), in the intestinal tumorigenesis Apcam1137 PIRC rat model. Over the course of this 20-week study, rats were fed a modified AIN-93G diet supplemented with 200 ppm naproxen, alone or in combination with TP-252 (1.5%, or 3% by weight). Rats treated with 200 ppm naproxen had 66% (p < 0.0001) fewer colon tumors than controls (AIN-93G) and an 81% (p < 0.0001) reduction in tumor size. However, when Naproxen was combined with high-dose TP-252 (3%), tumor number and size were reduced by 95% (p < 0.0001) and 98% (p < 0.0001) respectively, when compared to controls. Since the primary mechanisms of action for naproxen and EPA target COX metabolic activity, we performed a comprehensive lipidomic analysis on colon tissue and plasma to determine lipidomic changes associated with drug treatment. Increased formation of several EPA-derived eicosanoids, including 9-HEPE, 12-HEPE, 18-HEPE, and resolvin E2, whose mucosal levels correlated with both reduced tumor number and volume, were observed.
 These metabolites were also concomitantly elevated in the plasma of treated animals, representing potential pharmacodynamic (PD) biomarkers of CRC prevention. Future studies will decipher potential mechanisms that underlie these EPA-derived PD biomarkers and their role in tumor suppression. (Supported by the NCI Prevent Program 75N91019D00019, Task Order 75N91019F00132).
 Citation Format: Ryan Beach, Altaf Mohammed, Daniel W. Rosenberg. Identification of lipid pharmacodynamic biomarkers in FAP model [abstract]. In: Proceedings of the Second Biennial NCI Meeting: Translational Advances in Cancer Prevention Agent Development (TACPAD); 2022 Sep 7-9. Philadelphia (PA): AACR; Can Prev Res 2022;15(12 Suppl_2): Abstract nr A005.