Abstract 2128: TACH101, a first-in-class pan inhibitor of KDM4 histone lysine demethylases

Background: Alterations in epigenetic control can cause defective post-translational histone modification and dysregulation of gene activity leading to cancer development. Overexpression of KDM4, a demethylase of histone lysine 9 methyl 2/3 and lysine 36 methyl 2/3 (H3K9me2/3 and H3K36me2/3), is documented in a variety of cancers and is linked to aggressive disease and poor clinical outcomes. TACH101 is a novel first-in-class, selective and potent pan KDM4 inhibitor with favorable pharmacologic properties. Methods: TACH101 was evaluated using in vitro and in vivo studies including cell-proliferation assays in multiple cancer cell lines and patient-derived organoid models, apoptotic and cell cycle analyses, pharmacology studies in various animal species, and efficacy studies in xenograft tumor models. Results: Inhibition mechanism studies demonstrated TACH101 to be a reversible, α-ketoglutarate competitive, selective and potent inhibitor of KDM4 isoforms A-D with IC50 values less than 0.100 μM for all four isoforms. In vitro, TACH101 demonstrated potent increase of H3K36me3 levels (EC50 Conclusions: TACH101 is a potent pan inhibitor of KDM4 that is suggestive of broad potential in cancer treatment. Further preclinical evaluation is ongoing to advance the molecule into clinical trials. Citation Format: Sanghee Yoo, Chandtip Chandhasin, Joselyn R. Del Rosario, Young K. Chen, Jeff Stafford, Stephen Quake, Frank Perabo, Michael F. Clarke. TACH101, a first-in-class pan inhibitor of KDM4 histone lysine demethylases [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2128.