In vitro production of BMP-7 and noggin by adenoviral gene transfer and effects of prolonged delivery of BMP-7 and noggin on gene expression of bone sialoprotein (BSP) and osteocalcin (OCN) in OCCM cells in vitro and in vivo. (AI)OCCM cells transduced in vitro by Ad-BMP-7 produced immunodetectable BMP-7 and noggin. No measurable BMP-7 or noggin protein was found in NT and Ad-GFP-treated samples. (AII) OCCM cells transduced by Ad-NOGΔB2 secreted recombinant noggin into the culture medium. Furthermore, noggin was not detected in the conditioned media of OCCM cells in Ad-GFP and NT groups. (B) 72 hr following gene transfer of Ad-BMP-7, Ad-NOGΔB2, Ad-GFP, or NT to OCCM cells, BSP and OCN expression were examined by Northern blotting (B, left panel). The density of each band was measured by image analysis, and the values normalized against 18S rRNA (B, right panel). BMP-7 gene transfer increased BSP gene expression of OCCM cells by ~3-fold, compared with NT and Ad-GFP, while Ad-NOGΔB2 gene transfer inhibited BSP gene expression. OCN gene expression was modestly enhanced by Ad-BMP-7 gene transfer. Ad-NOGΔB2 gene transfer decreased OCN expression by ~50% compared with controls. (C) In vivo BSP and OCN expression in OCCM-PLGA implants at 3 and 6 weeks examined by Northern blotting. BSP and OCN expressions by Ad-NOGΔB2 treatment at 3 weeks were downregulated by ~2- and >3.5-fold, respectively, when compared with NT and Ad-GFP groups, while no differences in BSP and OCN gene expression were noted at 6 weeks.