The aim of this study was to develop recombinant human Bone Morphogenetic Protein-7 (BMP7)-stable cells and recombinant human BMP7 adenoviruses (AdBMP7) for osteoinduction and osteoregeneration in musculoskeletal diseases.

The human BMP7 cDNA was amplified from a human osteosarcoma cell line, U2OS using a reverse transcription-polymerase chain reaction and cloned into a eukaryotic expression vector. The BMP7-stable HEK293 cells (HEK293/BMP7) were prepared by transfecting the recombinant BMP7 plasmid vector. The recombinant human BMP7 adenovirus (AdBMP7) was constructed using the AdEasy vector system. The BMP7 expression levels in HEK293/BMP7 and AdBMP7 were measured by activity staining for alkaline phosphatase in mouse C2C12 promyoblast cells. The BMP7-stable HEK293 cells, AdBMP7 itself, or AdBMP7-transduced human fibroblasts were injected into the subcutaneous tissues and the calf muscles of immunocompromised mice. The amount of ectopic bone formation was evaluated by radiographic and histological analyses.

Ectopic bone formation was observed after injecting the BMP7-stable HEK293 cells with either the AdBMP7 itself or AdBMP7-transduced human fibroblasts into the subcutaneous tissues and calf muscles of immunocompromised mice.

These results showed that HEK293/BMP7 cells and AdBMP7 have a significant potential for bone formation and the regeneration of various bone diseases.