Abstract 4332: Targeting MYC overexpressing leukemia with cardiac glycoside proscillaridin through downregulation of histone acetyltransferases

Abstract

Abstract Targeting MYC oncogene remains a major therapeutic goal in anticancer therapies. Here, we demonstrate that proscillaridin, a cardiac glycoside approved for heart failure treatment, causing Na+/K+ pump inhibition, targets efficiently MYC overexpressing cancer cells. At clinically relevant doses, proscillaridin induced rapid downregulation of MYC protein level, and produced growth inhibition preferentially against MYC overexpressing leukemic cell lines including lymphoid and myeloid stem cell populations. Whole transcriptome analysis with RNA sequencing of acute lymphoblastic leukemia cells showed a downregulation of gene sets involved in MYC pathways and cell replication, and an upregulation of genes involved in hematopoietic differentiation induced by proscillaridin treatment. Gene expression changes were associated with an epigenetic remodeling of chromatin active marks. Proscillaridin induced a significant loss of lysine acetylation in histone H3 (at lysine 9, 14, 18 and 27). In addition, mass spectrometry analysis revealed a loss of lysine acetylation in non-histone proteins such as MYC itself, MYC target proteins, and a series of histone acetylation regulators. Global loss of acetylation correlated with the rapid downregulation of histone acetyltransferase proteins (such as CBP, P300, TIP60 and GCN5) involved in histone and MYC acetylation. Overall, these results strongly support the repurposing of proscillaridin in MYC overexpressing leukemia and suggest a novel strategy to target MYC by inducing the downregulation of histone acetyltransferases involved in its stability. Citation Format: Elodie Marie Da Costa, Gregory Armaos, Gabrielle McInnes, Annie Beaudry, Gael Moquin-Beaudry, Virginie Bertrand-Lehouillier, Maxime Caron, Pascal St-Onge, Jeffrey R. Jonhson, Nevan Krogan, Yuka Sai, Michale Downey, Moutih Rafei, Meaghan Boileau, Kolja Eppert, Ema Florez-Diaz, Andre Haman, Trang Hoang, Daniel Sinnett, Christian Beausejour, Serge McGraw, Noel J. Raynal. Targeting MYC overexpressing leukemia with cardiac glycoside proscillaridin through downregulation of histone acetyltransferases [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4332.