The Src inhibitor AZD0530 reversibly inhibits the formation and activity of human osteoclasts.
Tumor cells in the bone microenvironment are able to initiate a vicious cycle of bone degradation by mobilizing osteoclasts, multinucleated cells specialized in bone degradation. c-Src is highly expressed both in tumors and in osteoclasts. Therefore, drugs like AZD0530, designed to inhibit Src activity, could selectively interfere with both tumor and osteoclast activity. Here we explored the effects of AZD0530 on human osteoclast differentiation and activity. The effect on osteoclasts formed in vivo was assessed in mouse fetal calvarial explants and in isolated rabbit osteoclasts, where it dose-dependently inhibited osteoclast activity. Its effect on formation and activity of human osteoclasts in vitro was determined in cocultures of human osteoblasts and peripheral blood mononuclear cells. AZD0530 was most effective in inhibiting osteoclast-like cell formation when present at the onset of osteoclastogenesis, suggesting that Src activity is important during the initial phase of osteoclast formation. Formation of active phosphorylated c-Src, which was highly present in osteoclast-like cells in cocultures and in peripheral blood mononuclear cell monocultures, was significantly reduced by AZD0530. Furthermore, it reversibly prevented osteoclast precursor migration from the osteoblast layer to the bone surface and subsequent formation of actin rings and resorption pits. These data suggest that Src is pivotal for the formation and activity of human osteoclasts, probably through its effect on the distribution of the actin microfilament system. The reversible effect of AZD0530 on osteoclast formation and activity makes it a promising candidate to temper osteoclastic bone degradation in bone diseases with enhanced osteoclast activity such as osteolytic metastatic bone disease.
Oral Cell Biology, ACTA, Vrije Universiteit, Van der Boechorststraat 7, 1081 BT Amsterdam, the Netherlands. teun.devries@vumc.nl
Teun J
TJ
de Vries
Margriet G
MG
Mullender
Marion A
MA
van Duin
Cornelis M
CM
Semeins
Neil
N
James
Tim P
TP
Green
Vincent
V
Everts
Jenneke
J
Klein-Nulend
D000199:Actins / Q000378:metabolism; D000818:Animals; D052117:Benzodioxoles / Q000494:pharmacology*; D015153:Blotting, Western; D001862:Bone Resorption; D001842:Bone and Bones / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects*; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D018920:Coculture Techniques; D005260:Female; D005333:Fetus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D009924:Organ Culture Techniques; D010010:Osteoclasts / Q000187:drug effects*; D010766:Phosphorylation / Q000187:drug effects; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000037:antagonists & inhibitors*; D011799:Quinazolines / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011817:Rabbits; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012886:Skull / Q000166:cytology / Q000187:drug effects / Q000378:metabolism
D000199:Actins; D052117:Benzodioxoles; D011799:Quinazolines; D012333:RNA, Messenger; C515233:saracatinib; D016392:Proto-Oncogene Proteins pp60(c-src)