title: HA14-1 selectively induces apoptosis in Bcl-2-overexpressing leukemia/lymphoma cells, and enhances cytarabine-induced cell death.
abstract: The Bcl-2 oncoprotein is commonly overexpressed in hematological malignancy, where it promotes the survival of neoplastic cells. Recently, a small molecule (HA14-1) was reported to bind the surface pocket of Bcl-2 that mediates antiapoptotic interactions, triggering apoptosis in a Bcl-2-transfected cell line. We investigated the activity of this compound in a panel of malignant hematopoietic cell lines. Consistent with its proposed role as a Bcl-2 inhibitor, HA14-1 was most cytotoxic in lines expressing high levels of Bcl-2. In addition, at lower concentrations (5-12.5 muM), the compound predominantly triggered apoptosis. However, at concentrations two-fold higher than this and above, increasing primary necrosis was observed, suggesting the onset of interactions supplementary to Bcl-2 inhibition. In experiments on primary cells, 25 muM HA14-1 induced extensive apoptosis in acute leukemic blasts, but also suppressed normal hematopoietic colony formation to <50% of baseline. Importantly, low-concentration HA14-1 (5 muM) was nontoxic to normal colony-forming cells, whereas it enhanced the cytotoxicity of the antileukemia drug cytarabine in Bcl-2-positive lymphoblastic leukemia cells. In conclusion, our results indicate that HA14-1 at low concentration selectively triggers apoptosis in malignant hematopoietic cells that overexpress Bcl-2. Agents of this class may have particular utility in combination with cytotoxic chemotherapy drugs.
authors.affiliation: Leukaemia Foundation Research Unit, Queensland Institute of Medical Research, Brisbane, Australia.
authors.forename: J D
authors.initials: JD
authors.lastname: Lickliter
authors.forename: N J
authors.initials: NJ
authors.lastname: Wood
authors.forename: L
authors.initials: L
authors.lastname: Johnson
authors.forename: G
authors.initials: G
authors.lastname: McHugh
authors.forename: J
authors.initials: J
authors.lastname: Tan
authors.forename: F
authors.initials: F
authors.lastname: Wood
authors.forename: J
authors.initials: J
authors.lastname: Cox
authors.forename: N W
authors.initials: NW
authors.lastname: Wickham
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D001578:Benzopyrans / Q000494:pharmacology*; D001752:Blast Crisis / Q000473:pathology; D001854:Bone Marrow Cells / Q000187:drug effects / Q000473:pathology; D016923:Cell Death / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003561:Cytarabine / Q000633:toxicity*; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D019254:Genes, bcl-2; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000473:pathology; D006801:Humans; D007938:Leukemia / Q000473:pathology; D008223:Lymphoma / Q000473:pathology; D009570:Nitriles / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics*; D014407:Tumor Cells, Cultured
chemical_list: D001578:Benzopyrans; D004791:Enzyme Inhibitors; D009570:Nitriles; D019253:Proto-Oncogene Proteins c-bcl-2; C456800:ethyl 2-amino-6-bromo-4-(1-cyano-2-ethoxy-2-oxoethyl)-4H-chromene-3-carboxylate; D003561:Cytarabine