Composition-dependent protein secretion and integrin level of osteoblastic cell on calcium silicate cements

The purpose of this study was to investigate the responses of the human osteosarcoma cell line MG63 to calcium silicate cements with different Si/Ca molar ratios and different surface roughness. In particular, the study evaluated integrin subunit levels, phosphor-focal adhesion kinase (pFAK) levels and protein production at the cell attachment stage. The results indicated that the surface roughness (variations within a factor of 10) of the cements did not play a prominent role in cell attachment and proliferation, but the effect of composition was highlighted. Increased pFAK and total integrin levels and promoted cell attachment and cell cycle progression were observed upon an increase in cement Si content. Cement with a higher Si content was beneficial for collagen Type I (COL I) adsorption, COL I secretion, and αlibβ3 subintegrin expression, whereas cement with a higher Ca content increased fibronectin (FN) adsorption, FN secretion, and enhanced αvβ1 subintegrin levels. These results establish composition-dependent differences in integrin binding as a mechanism regulating cellular responses to biomaterial surfaces.