Abstract 521: Discovery of novel TNKS inhibitors through structure-based virtual screening

Abstract

Abstract More than 80% of colorectal cancers (CRCs) have somatic mutations in the adenomatous polyposis coli (APC) gene, which affects abnormal WNT/β-catenin signaling. Since inhibition of tankyrases (TNKS1 and TNKS2) belonging to the poly(ADP-ribose) polymerase family stabilizes AXINs and induces degradation of β-catenin, drug development as a therapeutic target for APC-mutated CRCs is required. To identify selective small molecule inhibitors of TNKS, we performed pharmacophore modeling and structural docking studies targeting nicotinamide, adenosine, and both binding subsites of TNKS. Among the 8 million compounds, 149 of the nicotinamide site binders, 23 of the adenosine site binders, and 15 of the dual-site binders of TNKS were selected through computer-based virtual screening. Using in vitro TNKS1 and TNKS2 enzyme assays, we identified that TI2-N17 and TI3-D11 significantly inhibited TNKS1 and TNKS2 enzyme activities at low nanomolar levels. TI2-N17 and TI3-D11 stabilized AXIN2, reduced active β-catenin, and downregulated β-catenin target genes in COLO320DM, APC-mutated CRC cells. Both compounds exhibited anticancer effects on COLO320DM and SW403 cells. In addition, the combination treatment of 5-Fluorouracil (5-FU), an anticancer agent for CRC patients, and these compounds synergistically inhibited the proliferation of CRC cells compared to single compound treatment. Our findings demonstrated that TI2-N17 and TI3-D11 are therapeutic candidates targeting TNKS for APC-mutated CRCs treatment and suggested that the combined treatment with the compounds and 5-FU chemotherapy may be an effective therapeutic strategy for APC-mutated CRCs. Based on these compounds, further study will develop potent and selective TNKS inhibitors by designing and synthesizing novel derivative compounds. Citation Format: Hwani Ryu, Hye-Ran Seo, Hyo Jeong Kim, Jiyeon Ahn. Discovery of novel TNKS inhibitors through structure-based virtual screening [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 521.