Abstract A011: Effect of IL-23 knockdown on obesity driven CRC in high-fat diet fed Apcmin/+ mice

Abstract

Abstract Colorectal cancer (CRC) is the 3rd common cancer in the United States with an estimated 151,030 new cases and 52,580 deaths in 2022. Several studies suggest that western-style diet-induced obesity contributes to CRC promotion via systemic inflammatory mediators. Recently, we have reported significant elevation of circulating IL-23 levels in obese human subjects (BMI>30). Also, TCGA gene expression data indicated IL-23A over expression in colonic tumors (CT) that correlated with tumor stage, patient obesity, nodal metastasis, and poor survival rates. Importantly, we have shown that IL-23 knockdown in Apc min/+ mice led to significant suppression of the intestinal tumors strongly supporting our hypothesis that pro-inflammatory cytokine IL-23 could be a possible link between obesity and CRC. Here we explored the contribution of IL-23 in obesity induce CRC in vivo using high-fat diet (HFD) fed Apc min/+ mouse model. For this study, Apc min/+ and IL-23 KO (IL-23A p19-/- mice; MMMRC) were cross-bred to generate Apc min/+ mice with IL-23 normal (IL-23+/+) or KO (IL-23-/-) genotypes. Six-week old Apc min/+ mice (N≥15/gender) were grouped by IL-23 genotypes and fed HFD (60 Kcal) until termination. Mice were euthanized at 20 weeks age, intestines were harvested and evaluated for tumors incidence and multiplicity. In Apc min/+ mice, IL-23 deletion had significant suppressive effect on HFD driven CT and small intestinal tumors (SIT). IL-23-/- Apc min/+ male mice had 50% less CT (0.81+0.25 vs 1.61±0.27; p<0.05) while female mice had 40% less CT (0.40±0.16 vs 0.94±0.21; p=0.05) compared to the IL-23+/+ Apc min/+ control mice. Similarly, CT incidence was also suppressed by 36% and 48% in male and female IL-23-/- Apc min/+ mice respectively compared to control mice. SIT multiplicity was also inhibited by 48% in male (15.00±1.13 vs 28.54±1.11; p<0.0001) and by 41% in female (14.83±1.35 vs 25.18±1.71; p<0.0005) IL23-/- Apc min/+ compared to control mice. Tumor data was complemented by significant reduction in markers of proliferation, immune evasion, circulating proinflammatory cytokine and chemokines (IL-1, IL- 17, IL-23, IL-10, CCL-3, CCL-2, CCL-5, IFNγ, TNFα, etc.) in IL-23 KO compared to control mice. Our data clearly indicates that IL-23 is a promising target for CRC prevention in high-risk obese individuals and warrants further investigation. (Supported in part by P30CA225520 and Kerley-Cade Endowed Chair). Citation Format: Venkateshwar Madka, Srikanth Chiliveru, Yuting Zhang, Nicole Stratton, Anh Bao, Nandini Kumar, Chinthalapally V. Rao. Effect of IL-23 knockdown on obesity driven CRC in high-fat diet fed Apcmin/+ mice [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 A011.