Abstract 2182: 15-lipoxygenase-1 modulation of colonic resolvin production to suppress colorectal carcinogenesis

Abstract

Abstract Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are widely used dietary supplements and FDA-approved treatments. The reported impacts of fish oil, DHA, and EPA on colorectal carcinogenesis (CRC) have spurred debates, as certain studies suggest promotional effects while numerous others emphasize suppressive effects. Nevertheless, resolvins, oxidative metabolites of EPA and DHA, exhibit the ability to inhibit crucial pathways (such as TNF-α and IL-1β) that contribute to CRC. 15-lipoxygenase-1 (ALOX15) plays a crucial role in the oxidative metabolism of DHA and EPA, ultimately leading to the formation of resolvins. However, ALOX15 expression is commonly lost during human CRC. Whether loss of ALOX15 expression modulates the effects of DHA and EPA on CRC remains to be elucidated. We therefore conducted the experiments in preclinical CRC mouse models induced by Azoxymethane or Apc gene mutation to explore the hypothesis that ALOX15 expression in colonic epithelial cells regulates DHA and EPA metabolism to generate resolvins, subsequently influencing CRC outcomes. We found that 1) DHA and EPA exert differential effects on CRC, which can be further modified by factors such as their formulation (e.g., ethyl ester versus triglyceride); 2) targeted transgenic expression of ALOX15 in the intestines of mice (referred to as ALOX15-Gut mice) markedly augmented the production of resolvins and concurrently suppressed CRC; 3) the predominant products from the expressed ALOX15 enzymatic activity were identified as 17-HDHA and resolvin D5; and 4) the effects ALOX15 on increasing resolvin generation and suppressing CRC were consistent across various promoters used to drive ALOX15 transgenic expression in mice. These findings collectively underscore the profound importance of ALOX15 intestinal expression as a host-related factor in resolvin generation from EPA and DHA, which subsequently contributes to the suppression of CRC. Citation Format: Xiangsheng Zuo, Yoshiyuki Kiyasu, Yi Liu, Micheline Moussalli, Bo Wei, Peiying Yang, Imad Shureiqi. 15-lipoxygenase-1 modulation of colonic resolvin production to suppress colorectal carcinogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2182.