Antiproliferative effects of insulin-like growth factor-binding protein-3 in mesenchymal chondrogenic cell line RCJ3.1C5.18. relationship to differentiation stage.
Chondrogenesis results from a complex equilibrium between chondrocyte proliferation and differentiation. Insulin-like growth factors (IGFs) have a crucial role in chondrogenesis, but their mechanisms of action are not well defined. IGF-binding protein-3 (IGFBP-3) is the major carrier for circulating IGFs in postnatal life, and has been shown to have IGF-independent effects on proliferation of several cancer cell lines. In this study, we have evaluated the IGF-independent and -dependent effects of IGFBP-3 on chondrocyte proliferation and the relationship of these effects with chondrocyte differentiation stage. We used the RCJ3.1C5.18 nontransformed mesenchymal chondrogenic cell line, which, over 2 weeks of culture, progresses through the differentiation pathway exhibited by chondrocytes in the growth plate. We demonstrated that IGFBP-3 inhibited, in a dose-dependent manner (1-30 nm), the proliferation of chondroprogenitors and early differentiated chondrocytes, stimulated by des-(1-3)-IGF-I and longR(3)-IGF-I (IGF-I analogs with reduced affinity for IGFBP-3), and by insulin and IGF-I. In terminally differentiated chondrocytes, IGFBP-3 retained the ability to inhibit cell proliferation stimulated by IGF-I, but had no effect on cell growth stimulated by insulin, or des-(1-3)-IGF-I or longR(3)IGF-I. By monolayer affinity cross-linking, we demonstrated a specific IGFBP-3-associated cell-membrane protein of approximately 20 kDa. We determined that IGFBP-3 has an antiproliferative effect on chondrocytes and, that this effect is related to the differentiation process. In chondroprogenitors and early differentiated chondrocytes, antiproliferative effect of IGFBP-3 is mainly IGF-independent, whereas, following terminal differentiation this effect is IGF-dependent.
Spagnoli
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A
Department of Pediatrics, Oregon Health Sciences University, Portland, Oregon 97201, the Research Department, Shriners Hospital for Children, Portland, Oregon 97201, USA. spagnoli@ohsu.edu
Hwa
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Horton
W A
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Lunstrum
G P
GP
Roberts
C T
CT
Chiarelli
F
F
Torello
M
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Rosenfeld
R G
RG
D002454:Cell Differentiation; D002455:Cell Division; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D020219:Chondrogenesis; D017077:Culture Media, Conditioned / Q000737:chemistry; D006131:Growth Inhibitors / Q000494:pharmacology; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000378:metabolism / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000031:analogs & derivatives; D008565:Membrane Proteins / Q000187:drug effects / Q000378:metabolism; D008648:Mesoderm / Q000166:cytology / Q000187:drug effects*; D011485:Protein Binding; D013002:Somatomedins / Q000378:metabolism
D017077:Culture Media, Conditioned; D006131:Growth Inhibitors; D018972:Insulin-Like Growth Factor Binding Protein 3; D008565:Membrane Proteins; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I