title: Bone building with bortezomib.
abstract: In this issue of the JCI, Mukherjee et al. report that bortezomib, a clinically available proteasome inhibitor active against myeloma, induces the differentiation of mesenchymal stem/progenitor cells (MSCs)--rather than mature osteoprogenitor cells--into osteoblasts, resulting in new bone formation (see the related article beginning on page 491). These results were observed when MSCs were implanted subcutaneously in mice or were used to treat a mouse model of postmenopausal bone loss. Others have reported that immunomodulatory drugs (e.g., thalidomide and lenalidomide), which are active against myeloma, also block the activity of bone-resorbing osteoclasts. These results reflect the utility of targeting endogenous MSCs for the purpose of tissue repair and suggest that combining different classes of agents that are antineoplastic and also inhibit bone destruction and increase bone formation should be very beneficial for myeloma patients suffering from severe bone disease.
authors.affiliation: Office of Research and Development, Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania 15240, USA.
authors.forename: G David
authors.initials: GD
authors.lastname: Roodman
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001847:Bone Diseases / Q000188:drug therapy / Q000209:etiology; D001897:Boronic Acids / Q000494:pharmacology* / Q000627:therapeutic use; D000069286:Bortezomib; D002454:Cell Differentiation; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects*; D051379:Mice; D009101:Multiple Myeloma / Q000150:complications / Q000188:drug therapy; D010006:Osteoblasts / Q000166:cytology*; D010012:Osteogenesis; D011480:Protease Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D011719:Pyrazines / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D000970:Antineoplastic Agents; D001897:Boronic Acids; D011480:Protease Inhibitors; D011719:Pyrazines; D000069286:Bortezomib