title: Osteogenic effects of a potent Src-over-Abl-selective kinase inhibitor in the mouse.
abstract: Src-null mice have higher bone mass because of decreased bone resorption and increased bone formation, whereas Abl-null mice are osteopenic, because of decreased bone formation. Compound I, a potent inhibitor of Src in an isolated enzyme assay (IC(50) 0.55 nM) and a Src-dependent cell growth assay, with lower activity on equivalent Abl-based assays, potently, but biphasically, accelerated differentiation of human mesenchymal stem cells to an osteoblast phenotype (1-10 nM). Compound I (≥0.1 nM) also activated osteoblasts and induced bone formation in isolated neonatal mouse calvariae. Compound I required higher concentrations (100 nM) to inhibit differentiation and activity of osteoclasts. Transcriptional profiling (TxP) of calvaria treated with 1 μM compound I revealed down-regulation of osteoclastic genes and up-regulation of matrix genes and genes associated with the osteoblast phenotype, confirming compound I's dual effects on bone resorption and formation. In addition, calvarial TxP implicated calcitonin-related polypeptide, β (β-CGRP) as a potential mediator of compound I's osteogenic effect. In vivo, compound I (1 mg/kg s.c.) increased vertebral trabecular bone volume 21% (microcomputed tomography) in intact female mice. Increased trabecular volume was also detected histologically in a separate bone, the femur, particularly in the secondary spongiosa (100% increase), which underwent a 171% increase in bone formation rate, a 73% increase in mineralizing surface, and a 59% increase in mineral apposition rate. Similar effects were observed in ovariectomized mice with established osteopenia. We conclude that the Src inhibitor compound I is osteogenic, presumably because of its potent stimulation of osteoblast differentiation and activation, possibly mediated by β-CGRP.
authors.affiliation: Department of Osteoporosis and Frailty, Women's Health and Musculoskeletal Biology, Wyeth Research, Collegeville, Pennsylvania, USA. murrills@aol.com
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Murrills
authors.forename: Shoichi
authors.initials: S
authors.lastname: Fukayama
authors.forename: Frank
authors.initials: F
authors.lastname: Boschelli
authors.forename: Jeanne J
authors.initials: JJ
authors.lastname: Matteo
authors.forename: Jane
authors.initials: J
authors.lastname: Owens
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Golas
authors.forename: Dharmesh
authors.initials: D
authors.lastname: Patel
authors.forename: Giovan
authors.initials: G
authors.lastname: Lane
authors.forename: Yao-Bin
authors.initials: YB
authors.lastname: Liu
authors.forename: Laura
authors.initials: L
authors.lastname: Carter
authors.forename: Jason
authors.initials: J
authors.lastname: Jussif
authors.forename: Vikki
authors.initials: V
authors.lastname: Spaulding
authors.forename: Yanong D
authors.initials: YD
authors.lastname: Wang
authors.forename: Diane H
authors.initials: DH
authors.lastname: Boschelli
authors.forename: John C
authors.initials: JC
authors.lastname: McKew
authors.forename: X Jian
authors.initials: XJ
authors.lastname: Li
authors.forename: Susan
authors.initials: S
authors.lastname: Lockhead
authors.forename: Colleen
authors.initials: C
authors.lastname: Milligan
authors.forename: Yogendra P
authors.initials: YP
authors.lastname: Kharode
authors.forename: Veronica
authors.initials: V
authors.lastname: Diesl
authors.forename: Yuchen
authors.initials: Y
authors.lastname: Bai
authors.forename: Max
authors.initials: M
authors.lastname: Follettie
authors.forename: Frederick J
authors.initials: FJ
authors.lastname: Bex
authors.forename: Barry
authors.initials: B
authors.lastname: Komm
authors.forename: Peter V N
authors.initials: PV
authors.lastname: Bodine
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002454:Cell Differentiation; D020869:Gene Expression Profiling; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects; D010010:Osteoclasts / Q000166:cytology / Q000187:drug effects; D010012:Osteogenesis / Q000187:drug effects*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D016315:Proto-Oncogene Proteins c-abl / Q000037:antagonists & inhibitors*; D019061:src-Family Kinases / Q000037:antagonists & inhibitors*
chemical_list: D047428:Protein Kinase Inhibitors; D016315:Proto-Oncogene Proteins c-abl; D019061:src-Family Kinases