Effect of celecoxib on Ca2+ movement and cell proliferation in human osteoblasts.
In human osteoblasts, the effect of the widely prescribed cyclooxygenase-2 inhibitor celecoxib on intracellular Ca(2+) concentrations ([Ca(2+)](i)) and cell proliferation was explored by using fura-2 and the tetrazolium assay, respectively. Celecoxib at concentrations greater than 1microM caused a rapid rise in [Ca(2+)](i) in a concentration-dependent manner ( EC 50= 10 microM). Celecoxib-induced [Ca(2+)](i) rise was reduced by 90% by removal of extracellular Ca(2+), and by 30% by l-type Ca(2+) channel blockers. Celecoxib-induced Mn(2+)-associated quench of intracellular fura-2 fluorescence also suggests that celecoxib-induced extracellular Ca(2+) influx. In Ca(2+)-free medium, thapsigargin, an inhibitor of the endoplasmic reticulum Ca(2+)-ATPase, caused a monophasic [Ca(2+)](i) rise, after which the increasing effect of celecoxib on [Ca(2+)](i) was greatly inhibited. Conversely, pretreatment with celecoxib to deplete intracellular Ca(2+) stores totally prevented thapsigargin from releasing more Ca(2+). U73122, an inhibitor of phoispholipase C, abolished histamine (an inositol 1,4,5-trisphosphate-dependent Ca(2+) mobilizer)-induced, but not celecoxib-induced, [Ca(2+)](i) rise. Pretreatment with phorbol 12-myristate 13-acetate and forskolin to activate protein kinase C and adenylate cyclase, respectively, partly inhibited celecoxib-induced [Ca(2+)](i) rise in Ca(2+)-containing medium. Separately, overnight treatment with 1-100microM celecoxib inhibited cell proliferation in a concentration-dependent manner. These findings suggest that in human osteoblasts, celecoxib increases [Ca(2+)](i) by stimulating extracellular Ca(2+) influx and also by causing intracellular Ca(2+) release from the endoplasmic reticulum via a phospholiase C-independent manner. Celecoxib may be cytotoxic at higher concentrations.
Department of Rehabilitation, Kaohsiung Veterans General Hospital, Kaohsiung 813, Taiwan, ROC.
Jue-L
JL
Wang
Ko-L
KL
Lin
Jin-S
JS
Chen
Yih-C
YC
Lu
Bang-P
BP
Jiann
Hong-T
HT
Chang
Shu-S
SS
Hsu
Wei-C
WC
Chen
Jong-K
JK
Huang
Chin-M
CM
Ho
Chung-R
CR
Jan
D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects*; D000068579:Celecoxib; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D016257:Fura-2 / Q000378:metabolism; D006801:Humans; D010006:Osteoblasts / Q000187:drug effects*; D011720:Pyrazoles; D013449:Sulfonamides / Q000494:pharmacology*; D013778:Tetrazolium Salts / Q000737:chemistry; D010738:Type C Phospholipases / Q000502:physiology
D000894:Anti-Inflammatory Agents, Non-Steroidal; D011720:Pyrazoles; D013449:Sulfonamides; D013778:Tetrazolium Salts; D010738:Type C Phospholipases; D000068579:Celecoxib; D002118:Calcium; D016257:Fura-2