title: Engineering 3-alkyltriazenes to block bcr-abl kinase: a novel strategy for the therapy of advanced bcr-abl expressing leukemias.
abstract: Recently, within the framework of a new strategy termed "combi-targeting," we designed ZRCM5 to contain a 2-phenylaminopyrimidopyridine moiety targeted to bcr-abl kinase and a triazene tail capable of generating a methyldiazonium species upon hydrolysis. The ability of ZRCM5 to block tyrosine kinase activity was tested in a short 10 min exposure ELISA involving isolated bcr-abl kinase and Western blotting assays. The results showed that: (a) ZRCM5 was hydrolyzed with a half-life of 27 min in cell culture media, (b) it blocked bcr-abl autophosphorylation in promyeloblastic leukemia K562 cells in a dose-dependent manner (IC(50)=14.01 microM) and (c) it induced dose-dependent levels of DNA strand breaks. In contrast, temozolomide (TEM), a clinical DNA damaging triazene capable of generating, like ZRCM5, a methyldiazonium species, could neither block bcr-abl tyrosine kinase activity in isolated enzyme nor in whole cell autophosphorylation assays. In cells expressing varied levels of bcr-abl, ZRCM5 was consistently more potent than TEM. The significant potency of ZRCM5 against the leukemia cells was attributed to its ability to simultaneously to block bcr-abl and related DNA repair activity while inducing significant DNA lesions in bcr-abl expressing leukemia cells. Further studies are ongoing to increase the affinity of ZRCM5 with the purpose of further enhancing its potency in bcr-abl expressing cells.
authors.affiliation: Cancer Drug Research Laboratory, Department of Medicine, Division of Medical Oncology, McGill University Health Center/Royal Victoria Hospital, 687 Pine Ave. West, M7.19, Montreal, Que., Canada H3A 1A1.
authors.forename: Athanasia
authors.initials: A
authors.lastname: Katsoulas
authors.forename: Zakaria
authors.initials: Z
authors.lastname: Rachid
authors.forename: Fouad
authors.initials: F
authors.lastname: Brahimi
authors.forename: James
authors.initials: J
authors.lastname: McNamee
authors.forename: Bertrand J
authors.initials: BJ
authors.lastname: Jean-Claude
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D003470:Culture Media / Q000737:chemistry; D004249:DNA Damage; D003606:Dacarbazine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D015195:Drug Design; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005434:Flow Cytometry; D016044:Fusion Proteins, bcr-abl; D006801:Humans; D006868:Hydrolysis; D020014:K562 Cells; D007938:Leukemia / Q000188:drug therapy / Q000201:enzymology* / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D000077204:Temozolomide; D013997:Time Factors; D014226:Triazenes / Q000378:metabolism / Q000494:pharmacology*; D020298:U937 Cells
chemical_list: D003470:Culture Media; D004791:Enzyme Inhibitors; D014226:Triazenes; D003606:Dacarbazine; D011505:Protein-Tyrosine Kinases; D016044:Fusion Proteins, bcr-abl; D000077204:Temozolomide