Abstract 2573: A novel regulation of the Wnt/β-catenin pathway involving NLRP12 during colorectal tumorigenesis

Abstract NLRP12, a member of the NOD-like receptor family, has been characterized as a negative regulator of NF-κB and MAPK pathways in immune cells. We previously demonstrated that Nlrp12-deficient mice are highly susceptible to azoxymethane plus dextran sodium sulfate induced colorectal tumorigenesis in mice. However, the precise mechanism of NLRP12-mediated protection against colorectal cancer (CRC) was poorly understood. RNA-seq analysis revealed that tumors of Nlrp12-deficient mice express higher levels of protooncogenes (cMyc, Ccnd1), Wnt target genes (Ctnnb1, Axin2, Yap1, Tcf3, Lgr5), matrix metalloproteinases, and epithelial to mesenchymal transition markers (Vim, Fn1, Foxc2, Zeb2, Ezh2) compared to wild-type tumor. Interestingly, higher expression of these genes in Nlrp12-deficient tumors was not linked to any inflammatory signaling pathways as there was no difference in the activation of NF-kB, ERK, JNK, AKT, and STAT3 signaling pathways between Nlrp12-/- and wild-type tumors. However, we observed higher activation of β-catenin in Nlrp12-deficient tumors. Using intestinal epithelial cell specific Nlrp12-conditional knockout mice we showed that Nlrp12 deficiency in intestinal epithelial cells leads to increased tumorigenesis, metastasis, and β-catenin activation. To further understand the role of NLRP12 in the regulation of the Wnt/β-catenin, we overexpressed NLRP12 in HEK293T cells and HCT116 cells followed by stimulation with Wnt ligand Wnt3A. NLRP12 overexpressed cells showed significantly reduced activation of β-catenin and expression of Wnt target genes. Consistently, knocking down of NLRP12 in HEK293T and HCT116 cells caused higher activation of the Wnt/β-catenin pathway. Further biochemical analysis revealed that NLRP12-mediated suppression of β-catenin activation is associated with reduced phosphorylation of GSK3β. Interestingly, human and mouse colorectal tumors showed reduced expression of NLRP12 along with increased activation of β-catenin and GSK3β phosphorylation. Altogether, these data suggest that NLRP12 is a potent negative regulator of the Wnt/β-catenin pathway in colorectal tumor cells, and the NLRP12-GSK3β axis could be a novel target for CRC treatment. Citation Format: Shahanshah Khan, Lan Peng, Cheryl M. Lewis, Yunpeng Gao, Ram S. Mani, Hasan Zaki. A novel regulation of the Wnt/β-catenin pathway involving NLRP12 during colorectal tumorigenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2573.