title: Inhibition of wild-type and mutant Bcr-Abl by AP23464, a potent ATP-based oncogenic protein kinase inhibitor: implications for CML.
abstract: The deregulated, oncogenic tyrosine kinase Bcr-Abl causes chronic myeloid leukemia (CML). Imatinib mesylate (Gleevec, STI571), a Bcr-Abl kinase inhibitor, selectively inhibits proliferation and promotes apoptosis of CML cells. Despite the success of imatinib mesylate in the treatment of CML, resistance is observed, particularly in advanced disease. The most common imatinib mesylate resistance mechanism involves Bcr-Abl kinase domain mutations that impart varying degrees of drug insensitivity. AP23464, a potent adenosine 5'-triphosphate (ATP)-based inhibitor of Src and Abl kinases, displays antiproliferative activity against a human CML cell line and Bcr-Abl-transduced Ba/F3 cells (IC(50) = 14 nM; imatinib mesylate IC(50) = 350 nM). AP23464 ablates Bcr-Abl tyrosine phosphorylation, blocks cell cycle progression, and promotes apoptosis of Bcr-Abl-expressing cells. Biochemical assays with purified glutathione S transferase (GST)-Abl kinase domain confirmed that AP23464 directly inhibits Abl activity. Importantly, the low nanomolar cellular and biochemical inhibitory properties of AP23464 extend to frequently observed imatinib mesylate-resistant Bcr-Abl mutants, including nucleotide binding P-loop mutants Q252H, Y253F, E255K, C-terminal loop mutant M351T, and activation loop mutant H396P. AP23464 was ineffective against mutant T315I, an imatinib mesylate contact residue. The potency of AP23464 against imatinib mesylate-refractory Bcr-Abl and its distinct binding mode relative to imatinib mesylate warrant further investigation of AP23464 for the treatment of CML.
authors.affiliation: Howard Hughes Medical Institute, Oregon Health and Science University, L592, 3181 SW Sam Jackson Park Rd, Portland, OR 97239, USA. oharet@ohsu.edu
authors.forename: Thomas
authors.initials: T
authors.lastname: O'Hare
authors.forename: Roy
authors.initials: R
authors.lastname: Pollock
authors.forename: Eric P
authors.initials: EP
authors.lastname: Stoffregen
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Keats
authors.forename: Omar M
authors.initials: OM
authors.lastname: Abdullah
authors.forename: Erika M
authors.initials: EM
authors.lastname: Moseson
authors.forename: Victor M
authors.initials: VM
authors.lastname: Rivera
authors.forename: Hao
authors.initials: H
authors.lastname: Tang
authors.forename: Chester A
authors.initials: CA
authors.lastname: Metcalf
authors.forename: Regine S
authors.initials: RS
authors.lastname: Bohacek
authors.forename: Yihan
authors.initials: Y
authors.lastname: Wang
authors.forename: Raji
authors.initials: R
authors.lastname: Sundaramoorthi
authors.forename: William C
authors.initials: WC
authors.lastname: Shakespeare
authors.forename: David
authors.initials: D
authors.lastname: Dalgarno
authors.forename: Tim
authors.initials: T
authors.lastname: Clackson
authors.forename: Tomi K
authors.initials: TK
authors.lastname: Sawyer
authors.forename: Michael W
authors.initials: MW
authors.lastname: Deininger
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Druker
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology*; D000596:Amino Acids / Q000235:genetics / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects; D001549:Benzamides; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D016044:Fusion Proteins, bcr-abl / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D018922:HL-60 Cells; D006801:Humans; D000068877:Imatinib Mesylate; D020128:Inhibitory Concentration 50; D020014:K562 Cells; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D008894:Milk Proteins / Q000378:metabolism; D008958:Models, Molecular; D009154:Mutation / Q000235:genetics*; D009687:Nuclear Proteins / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D019000:Phosphotyrosine / Q000378:metabolism; D010879:Piperazines / Q000737:chemistry / Q000494:pharmacology; D017434:Protein Structure, Tertiary; D011728:Pyridones / Q000737:chemistry / Q000494:pharmacology; D011743:Pyrimidines / Q000737:chemistry / Q000494:pharmacology; D050799:STAT5 Transcription Factor; D015534:Trans-Activators / Q000378:metabolism
chemical_list: C493107:AP23464; D048868:Adaptor Proteins, Signal Transducing; D000596:Amino Acids; D001549:Benzamides; C082869:CRKL protein; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D008894:Milk Proteins; D009687:Nuclear Proteins; C403095:PD 173955; D010879:Piperazines; D011728:Pyridones; D011743:Pyrimidines; D050799:STAT5 Transcription Factor; D015534:Trans-Activators; D019000:Phosphotyrosine; D000068877:Imatinib Mesylate; D000255:Adenosine Triphosphate; D016044:Fusion Proteins, bcr-abl