Overproduction of recombinant human bone morphogenetic protein-7 in Chinese hamster ovary cells

Bone morphogenetic protein-7 is a multifunctional growth factor involved in various cellular processes such as osteogenesis, kidney and eye development, brown adipogenesis, and bone metastasis, and thus has been considered to have therapeutic potential for treating various diseases. In this study, we established a Chinese hamster ovary (CHO) cell line stably overexpressing recombinant human BMP-7 (rhBMP-7). Over the course of a 14-day fed-batch culture process in a 7.5-l bioreactor (5-l working volume) using chemically defined medium, the established cells could produce over 188 mg/l of rhBMP-7 protein. The rhBMP-7 was purified to homogeneity from the culture supernatant using a two-step chromatographic procedure that resulted in a recovery rate of approximately 55%, with protein purity greater than 95%. The purified rhBMP-7 was further demonstrated to be functionally active by measuring the proliferation of MC3T3-E1 cells, revealing a half-maximal effective concentration of 28.31 ng/ml.