Abstract A23: Identification of KJ-Pyr-9 as a potent MYC inhibitor

Abstract

Abstract We have identified a novel small-molecule inhibitor of MYC, KJ-Pyr-9, from a Kröhnke pyridine library. KJ-Pyr-9 functions as an inhibitor of MYC in biochemical assays, in cells and in xenograft experiments. In vitro, KJ-Pyr-9 binds to MYC as well as MYC-MAX dimers and can disrupt binding of MYC-MAX dimers with E-box DNA. In cells, MYC-MAX dimerization can be disrupted in cells as demonstrated by protein fragment complementation assays. KJ-Pyr-9 disrupts the transcriptional targets of MYC. The P493-6 cell line has tetracycline regulatable MYC expression. For this cell line, the transcriptional targets of MYC can be readily observed upon the addition of 0.1 ug/mL doxycycline. Both doxycycline and KJ-Pyr-9 negatively regulate MYC transcriptional signatures as determined by GSEA. The growth of a variety of different MYC-dependent cell lines is inhibited, including MYC-translocated Burkitt's lymphoma cell lines expressing high levels of MYC as well as solid tumor cell lines expressing moderate amounts of MYC. In vivo, KJ-Pyr-9 effectively blocks the growth of a xenotransplant of MYC-amplified human cancer cells. Acknowledgements: This work was supported by the National Cancer Institute under award number R01 CA078230 (PKV), The Skaggs Institute for Chemical Biology (KDJ) and by the Austrian Science Fund (FWF) grant P23652 (KB). This is manuscript 25089 of The Scripps Research Institute. Citation Format: Jonathan R. Hart, Klaus Bister, Kim D. Janda, Peter K. Vogt. Identification of KJ-Pyr-9 as a potent MYC inhibitor. [abstract]. In: Proceedings of the AACR Special Conference on Myc: From Biology to Therapy; Jan 7-10, 2015; La Jolla, CA. Philadelphia (PA): AACR; Mol Cancer Res 2015;13(10 Suppl):Abstract nr A23.