title: Role of decorin in the antimyeloma effects of osteoblasts.
abstract: Building on our previous report that osteoblasts and increased bone formation have a negative impact on myeloma cell growth in a subset of patients, we investigated the role of decorin, the main small leucine-rich proteoglycan (SLRP) expressed and produced by osteoblasts, in the antimyeloma effects of osteoblasts. In coculture experiments with osteoblasts, primary myeloma cell survival was significantly higher when decorin expression in osteoblasts was knocked down by short-hairpin RNA. Coculture experiments of myeloma cells and supporting osteoclasts in the presence of osteoblast-conditioned medium showed reduced myeloma cell survival, an effect that was attenuated by decorin-neutralizing antibody. Decorin overexpression in mesenchymal stem cells or use of recombinant decorin in coculture with osteoclasts reduced the ability of osteoclasts to support primary myeloma cell survival. The antimyeloma effect of decorin involved direct induction of apoptosis and activation of p21(WAF). Decorin also inhibited myeloma cell-induced tube formation and osteoclast differentiation. Decorin expression was insignificantly lower in patients' than donors' osteoblasts and slightly increased by bortezomib. Certain SLRPs are involved in the antimyeloma effect of osteoblasts directly and indirectly through inhibition of angiogenesis and osteoclastogenesis; therefore, increasing endogenous or exogenous SLRPs in myelomatous bone may help control myeloma.
authors.affiliation: Myeloma Institute for Research and Therapy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.forename: Angela
authors.initials: A
authors.lastname: Pennisi
authors.forename: Shmuel
authors.initials: S
authors.lastname: Yaccoby
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis; D001483:Base Sequence; D001897:Boronic Acids / Q000494:pharmacology; D000069286:Bortezomib; D049109:Cell Proliferation; D002470:Cell Survival; D018920:Coculture Techniques; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000502:physiology; D058575:Decorin; D016326:Extracellular Matrix Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D005822:Genetic Vectors; D006801:Humans; D016086:Lentivirus / Q000235:genetics; D059630:Mesenchymal Stem Cells / Q000473:pathology / Q000502:physiology; D009101:Multiple Myeloma / Q000473:pathology / Q000503:physiopathology*; D009389:Neovascularization, Pathologic / Q000517:prevention & control; D010006:Osteoblasts / Q000187:drug effects / Q000473:pathology / Q000502:physiology*; D010950:Plasma Cells / Q000473:pathology; D011509:Proteoglycans / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D011719:Pyrazines / Q000494:pharmacology; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics
chemical_list: D000970:Antineoplastic Agents; D001897:Boronic Acids; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; C546878:DCN protein, human; D058575:Decorin; D016326:Extracellular Matrix Proteins; D011509:Proteoglycans; D011719:Pyrazines; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D000069286:Bortezomib