Effects of a hydroxyapatite-based biomaterial on gene expression in osteoblast-like cells.

Biostite is a hydroxyapatite-derived biomaterial that is used in periodontal and bone reconstructive procedures due to its osteoconductive properties. Since the molecular effects of this biomaterial on osteoblasts are still unknown, we decided to assess whether it may specifically modulate osteoblast functions in vitro. We found that a brief exposure to Biostite significantly reduced the proliferation of MG-63 and SaOS-2 osteoblast-like cells to approximately 50% of the plateau value. Furthermore, gene array analysis of MG-63 cells showed that Biostite caused a differential expression of 37 genes which are involved in cell proliferation and interaction, and related to osteoblast differentiation and tissue regeneration. Results were confirmed by RT-PCR, Western blot, and by an increase in alkaline phosphatase (ALP) specific activity. Biostite also increased levels of polycystin-2, a mechano-sensitive Ca(2+) channel, a promising new marker of bone cell differentiation. Biostite, therefore, may directly affect osteoblasts by enhancing chondro/osteogenic gene expression and cytoskeleton-related signaling pathways, which may contribute to its clinical efficacy.