Abstract 1810: Development of new phthalic hydrazide scaffold for potent TNKS inhibitors

Abstract Tankyrase 1 and 2 (TNKS1/2) catalyze post-translational modifications of target proteins through poly-ADP-ribosylation. Inhibition of TNKS stabilizes AXIN and induces β-catenin degradation in adenomatous polyposis coli (APC)-mutated colorectal cancer (CRC) cells. Therefore, TNKS emerges as a therapeutic target for APC mutant CRC, and there is a critical need for drug development against it. Tankyrase 1 and 2 (TNKS1/2) catalyze the post-translational modification of target proteins through poly-ADP-ribosylation. Their inhibition stabilizes AXIN and induces β-catenin degradation. Therefore, TNKS is a therapeutic target for APC mutant colorectal cancer (CRC), and there is a need for drug development against it. However, reported TNKS inhibitors have serious limitations in that they cause intestinal toxicity. To address these issues and enhance efficacy, we synthesized 60 compounds based on the tetrahydrophthalazine scaffold using protein structure modeling-Al technology. Using an in vitro TNKS1 and TNKS2 enzyme assay and derivatizing Hit compounds, we confirmed that TI-61987 significantly inhibits TNKS enzyme activity at low nanomolar levels. TI-61987 stabilized AXIN2, reduced active β-catenin, and downregulated β-catenin target genes in COLO320DM, APC-mutated CRC cells. Additionally, TI-61987 exhibited excellent anticancer effects not only in COLO320DM cells but also in in vivo xenograft mouse models. Our findings demonstrate that TI-61987 is a therapeutic candidate targeting TNKS for the treatment of APC-mutated CRCs, and this anticancer drug may represent an effective therapy regimen for APC-mutated CRCs. Citation Format: Hwani Ryu, Hye-Ran Seo, Ju Han Lee, Kyu Myung Lee, Jiyeon Ahn. Development of new phthalic hydrazide scaffold for potent TNKS inhibitors [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 1810.