Dual Lysosomal-Mitochondrial Targeting by Antihistamines to Eradicate Leukemic Cells

Background: Despite great efforts to identify druggable molecular targets for hematological neoplasias, there remains an unmet need for more effective therapies. Methods: We screened FDA-approved drugs that may revert an early transformation gene signature. Hit compounds were validated in a primary in vitro screening, using AML cell lines. Cytotoxic and differentiation effect was determined both in primary AML patient samples and healthy donor blood cells. Xenotrasplantation assays were performed to determine the in vivo therapeutic effect of hit compounds. The mechanism of action responsible for the antileukemic effect was studied focussing on lysosomes and mitochondria. Findings: We identified a group of antihistamines (termed ANHAs) with distinct physicochemical properties associated with their cationic-amphiphilic nature, that selectively killed leukemic cells. ANHAs behaved as antileukemic agents against primary myeloid and lymphoblastic leukemia samples ex vivo, sparing healthy cells. Moreover, ANHAs severely impaired leukemic stem cell functionality in vivo. ANHAs' cytotoxicity relied on simultaneous mitochondrial and lysosomal disruption and induction of autophagy and apoptosis. The pharmacological effect was exerted based on their physicochemical properties that permitted the passive targeting of both organelles, without the involvement of active molecular recognition. Interpretation: Dual targeting of lysosomes and mitochondria has emerged as a new promising therapeutic approach for eradication of leukemia. Funding Statement: RMR is supported by Ramon y 47 Cajal program of the Spanish Ministry of Economy (RYC-2011-07998 and IEDI-2016-00740), and JMCM is supported by Fundacion Mutua Madrilena. This work was funded by the Fundacion Mutua Madrilena (RMR), CaixaImpulse CI16-00003 (RMR), SAF2015-66721-P from MINECO (RMR), the Josep Carreras International Leukaemia Foundation (RMR), l’Obra Social “La Caixa”-Fundacio Bancaria “La Caixa” (RMR), and CERCA Programme/Generalitat de Catalunya (IJC). Declaration of Interests: RMR is a shareholder of Leukos Biotech. No other conflicts of interest reported. Ethical Approval Statement: All patients provided written informed consent in accordance with the Declaration of Helsinki, and the study was approved by the corresponding Ethics Committees (Ethics ommittee Hospital Clinic de Barcelona, Ethics Committee Hospital Germans Trias i Pujol). All experiments involving mice were approved by the Catalan Ethical Committee of Animal Experimentation (CCEEA).