Effects of CTGF/Hcs24, a hypertrophic chondrocyte-specific gene product, on the proliferation and differentiation of osteoblastic cells in vitro

J Cell Physiol. 2000 Aug;184(2):197-206. doi: 10.1002/1097-4652(200008)184:2<197::AID-JCP7>3.0.CO;2-R.


Connective tissue growth factor/hypertrophic chondrocyte-specific gene product Hcs24 (CTGF/Hcs24) promotes the proliferation and differentiation of chondrocytes and endothelial cells which are involved in endochondral ossification (Shimo et al., 1998, J Biochem 124:130-140; Shimo et al., 1999, J Biochem 126:137-145; Nakanishi et al., 2000, Endocrinology 141:264-273). To further clarify the role of CTGF/Hcs24 in endochondral ossification, here we investigated the effects of CTGF/Hcs24 on the proliferation and differentiation of osteoblastic cell lines in vitro. A binding study using (125)I-labeled recombinant CTGF/Hcs24 (rCTGF/Hcs24) disclosed two classes of specific binding sites on a human osteosarcoma cell line, Saos-2. The apparent dissociation constant (Kd) value of each binding site was 17.2 and 391 nM, respectively. A cross-linking study revealed the formation of (125)I-rCTGF/Hcs24-receptor complex with an apparent molecular weight of 280 kDa. The intensity of (125)I-rCTGF/Hcs24-receptor complex decreased on the addition of increasing concentrations of unlabeled rCTGF/Hcs24, but not platelet-derived growth factor-BB homodimer or basic fibroblast growth factor. These findings suggest that osteoblastic cells have specific receptor molecules for CTGF/Hcs24. rCTGF/Hcs24 promoted the proliferation of Saos-2 cells and a mouse osteoblast cell line MC3T3-E1 in a dose- and time-dependent manner. rCTGF/Hcs24 also increased mRNA expression of type I collagen, alkaline phosphatase, osteopontin, and osteocalcin in both Saos-2 cells and MC3T3-E1 cells. Moreover, rCTGF/Hcs24 increased alkaline phosphatase activity in both cells. It also stimulated collagen synthesis in MC3T3-E1 cells. Furthermore, rCTGF/Hcs24 stimulated the matrix mineralization on MC3T3-E1 cells and its stimulatory effect was comparable to that of bone morphogenetic protein-2. These findings indicate that CTGF/Hcs24 is a novel, potent stimulator for the proliferation and differentiation of osteoblasts in addition to chondrocytes and endothelial cells. Because of these functions, we are re-defining CTGF/Hcs24 as a major factor to promote endochondral ossification to be called "ecogenin: endochondral ossification genetic factor."

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3 Cells / cytology
  • 3T3 Cells / enzymology
  • Adenosine Triphosphatases / metabolism
  • Alkaline Phosphatase / metabolism
  • Animals
  • Binding, Competitive / drug effects
  • Blotting, Northern
  • Bone Morphogenetic Protein 2
  • Bone Morphogenetic Proteins / pharmacology
  • Calcification, Physiologic / drug effects
  • Cell Differentiation / drug effects
  • Cell Division / drug effects
  • Collagen / biosynthesis
  • Connective Tissue Growth Factor
  • Growth Substances / metabolism*
  • Growth Substances / pharmacology
  • Humans
  • Immediate-Early Proteins / metabolism*
  • Immediate-Early Proteins / pharmacology
  • Intercellular Signaling Peptides and Proteins*
  • Mice
  • Mitogens / metabolism*
  • Mitogens / pharmacology
  • Osteoblasts / cytology*
  • Osteoblasts / drug effects
  • Osteoblasts / metabolism
  • Proteins / metabolism*
  • Proteins / pharmacology
  • RNA, Messenger / drug effects
  • RNA, Messenger / metabolism
  • Receptors, Cell Surface / metabolism
  • Recombinant Proteins
  • Transforming Growth Factor beta / pharmacology
  • Tumor Cells, Cultured


  • BMP2 protein, human
  • Bmp2 protein, mouse
  • Bone Morphogenetic Protein 2
  • Bone Morphogenetic Proteins
  • CCN2 protein, human
  • CCN2 protein, mouse
  • Growth Substances
  • Immediate-Early Proteins
  • Intercellular Signaling Peptides and Proteins
  • Mitogens
  • Proteins
  • RNA, Messenger
  • Receptors, Cell Surface
  • Recombinant Proteins
  • Transforming Growth Factor beta
  • recombinant human bone morphogenetic protein-2
  • Connective Tissue Growth Factor
  • Collagen
  • Alkaline Phosphatase
  • Adenosine Triphosphatases