An adhesion variant of the MG-63 XXXX cell line displays an osteoblast-like phenotype.

@entity1 @entity41907 @entity5 @entity1421 @entity78 @entity13488 @entity421 @entity11599
MG-63 @entity1 @entity421 cells were selected for attachment and growth in increasing concentrations of a synthetic peptide containing the cell attachment-promoting @entity11599 (RGD) sequence derived from the cell-binding region of fibronectin. Cells capable of attachment and growth in 5 mM concentrations of a peptide having the sequence @entity41907 overproduce the cell surface receptor for fibronectin. No increase in fibronectin receptor gene copy number was detected by Southern blot analysis. The peptide-resistant MG-63.3A cells look very different from the MG-63 cells and resemble osteocytes. The resistant cells also grow more slowly than MG-63 cells. The enhanced expression of the fibronectin receptor on the resistant cells indicates that cells can regulate the amount of this receptor on their surface in response to environmental factors and that this may affect the phenotypic properties of the cell. MG-63.3A cells differ from MG-63 cells in their ability to form a calcified matrix in vitro and in their increased synthesis of type I collagen. The MG-63.3A cells synthesize 50-100-fold less @entity1421 , a mediator of bone resorption, than MG-63 cells. There is an overall down-regulation of chondroitin sulphate proteoglycans in MG-63.3A cells. These results are consistent with the hypothesis that such proteoglycans interfere with @entity78 deposition and with the observation that @entity13488 is increased in a wide variety of @entity5 but is absent or in small amounts in normal tissue. We conclude that MG-63.3A cells represent a more differentiated cell type with osteoblast-like properties.
