The Combination of Curaxin CBL0137 and Histone Deacetylase Inhibitor Panobinostat Delays KMT2A-Rearranged Leukemia Progression

Rearrangements of the Mixed Lineage Leukemia (MLL/KMT2A) gene are present in approximately 10% of acute leukemias and characteristically define disease with poor outcome. Driven by the unmet need to develop better therapies for KMT2A-rearranged leukemia, we previously discovered that the novel anti-cancer agent, curaxin CBL0137, induces decondensation of chromatin in cancer cells, delays leukemia progression and potentiates standard of care chemotherapies in preclinical KMT2A-rearranged leukemia models. Based on the promising potential of histone deacetylase (HDAC) inhibitors as targeted anti-cancer agents for KMT2A-rearranged leukemia and the fact that HDAC inhibitors also decondense chromatin via an alternate mechanism, we investigated whether CBL0137 could potentiate the efficacy of the HDAC inhibitor panobinostat in KMT2A-rearranged leukemia models. The combination of CBL0137 and panobinostat rapidly killed KMT2A-rearranged leukemia cells by apoptosis and significantly delayed leukemia progression and extended survival in an aggressive model of MLL-AF9 (KMT2A:MLLT3) driven murine acute myeloid leukemia. The drug combination also exerted a strong anti-leukemia response in a rapidly progressing xenograft model derived from an infant with KMT2A-rearranged acute lymphoblastic leukemia, significantly extending survival compared to either monotherapy. The therapeutic enhancement between CBL0137 and panobinostat in KMT2A-r leukemia cells does not appear to be mediated through cooperative effects of the drugs on KMT2A rearrangement-associated histone modifications. Our data has identified the CBL0137/panobinostat combination as a potential novel targeted therapeutic approach to improve outcome for KMT2A-rearranged leukemia

MLL-TFE3: a novel and aggressive KMT2A fusion identified in infant leukemia

Key Points A novel KMT2A-rearrangement, MLL-TFE3, was identified in an infant leukemia patient. MLL-TFE3 expression produces aggressive leukemia in a mouse model

Platinum(II) and gold(I) complexes based on 1,1 '-bis(diphenylphosphino)metallocene derivatives: Synthesis, characterization and biological activity of the gold complexes

The synthesis of series of 1,2,1' substituted bis(diphenylphosphino)- ruthenocenyl (1-4) and ferrocenyl cis-platinum(II) (5-7) and gold(I) (8-12) complexes are described. Crystal structures of 2 and 4, as well as 5, 6 and 10 confirm the molecular geometry of these ligands and their metal complexes. Preliminary investigation of four gold complexes as potential anticancer, antiHIV and antimalaria showed at least one gold compound that has excellent activity towards one of these diseases. The three gold(I) complexes, {1- [1-(dimethylamino)ethyl]-1 ,2-bis(diphenylphosphino)ruthenocene-kappa P-2,P'}bis[chlorogold(I)] (8) (IC50 = 1.40 mu M), {1-[1-(acetoxyethyl)-1',2-bis(diphenylphosphino)ferrocene-kappa P-2,P']bis[chlorogold(1)] (9) (IC50 = 0.51 mu M), {1-[1-(3-carboxypropanamido)ethyl]-1',2-bis(diphenylphosphino)-ruthenocene kappa P-2,P'} bis[chlorogold(I)] (12) (IC50 = 1.784 mu M), have the best activities against cancer, HIV and malaria respectively. (C) 2012 Elsevier B.V. All rights reserved

Epigenetic activation of plasmacytoid DC drives IFNAR-dependent therapeutic differentiation of AML

Pharmacologic inhibition of epigenetic enzymes can have therapeutic benefit against hematologic malignancies. In addition to affecting tumor cell growth and proliferation, these epigenetic agents may induce antitumor immunity. Here, we discovered a novel immunoregulatory mechanism through inhibition of histone deacetylases (HDAC). In models of acute myeloid leukemia (AML), leukemia cell differentiation and therapeutic benefit mediated by the HDAC inhibitor (HDACi) panobinostat required activation of the type I interferon (IFN) pathway. Plasmacytoid dendritic cells (pDC) produced type I IFN after panobinostat treatment, through transcriptional activation of IFN genes concomitant with increased H3K27 acetylation at these loci. Depletion of pDCs abrogated panobinostat-mediated induction of type I IFN signaling in leukemia cells and impaired therapeutic efficacy, whereas combined treatment with panobinostat and IFNα improved outcomes in preclinical models. These discoveries offer a new therapeutic approach for AML and demonstrate that epigenetic rewiring of pDCs enhances antitumor immunity, opening the possibility of exploiting this approach for immunotherapies.Jessica M. Salmon, Izabela Todorovski, Kym L. Stanley, Claudia Bruedigam, Conor J. Kearney, Luciano G. Martelotto, Fernando Rossello, Timothy Semple, Gisela Mir Arnau, Magnus Zethoven, Michael Bots, Stefan Bjelosevic, Leonie A. Cluse, Peter J. Fraser, Veronique Litalien, Eva Vidacs, Kate McArthur, Antony Y. Matthews, Elise Gressier, Nicole A. de Weerd, Jens Lichte, Madison J. Kelly, Simon J. Hogg, Paul J. Hertzog, Lev M. Kats, Stephin J. Vervoort, Daniel D. De Carvalho, Stefanie Scheu, Sammy Bedoui, Benjamin T. Kile, Steven W. Lane, Andrew C. Perkins, Andrew H. Wei, Pilar M. Dominguez, and Ricky W. Johnston