title: Cathepsin K: its skeletal actions and role as a therapeutic target in osteoporosis.
abstract: Bone remodeling consists of two phases--bone resorption and bone formation--that are normally balanced. When bone resorption exceeds bone formation, pathologic processes, such as osteoporosis, can result. Cathepsin K is a member of the papain family of cysteine proteases that is highly expressed by activated osteoclasts. Cathepsin K readily degrades type I collagen, the major component of the organic bone matrix. With such a major role in the initial process of bone resorption, cathepsin K has become a therapeutic target in osteoporosis. The antiresorptive properties of cathepsin K inhibitors have been studied in phase I and phase II clinical trials. Phase III studies are currently underway for odanacatib, a selective cathepsin K inhibitor.
authors.affiliation: Metabolic Bone Diseases Unit, Division of Endocrinology, Department of Medicine, College of Physicians and Surgeons, Columbia University, 630 W. 168th Street, New York, NY 10032, USA.
authors.forename: Aline G
authors.initials: AG
authors.lastname: Costa
authors.forename: Natalie E
authors.initials: NE
authors.lastname: Cusano
authors.forename: Barbara C
authors.initials: BC
authors.lastname: Silva
authors.forename: Serge
authors.initials: S
authors.lastname: Cremers
authors.forename: John P
authors.initials: JP
authors.lastname: Bilezikian
mesh_terms: D016723:Bone Remodeling / Q000187:drug effects / Q000502:physiology*; D056657:Cathepsin K / Q000037:antagonists & inhibitors / Q000378:metabolism*; D017321:Clinical Trials, Phase I as Topic; D017322:Clinical Trials, Phase II as Topic; D015195:Drug Design; D004791:Enzyme Inhibitors / Q000627:therapeutic use; D006801:Humans; D010024:Osteoporosis / Q000188:drug therapy / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; C534130:CTSK protein, human; D056657:Cathepsin K