[Stability analysis of CHO cell line expressing heterologous rhBMP2]

Bone morphogenetic protein 2 (BMP2), which belongs to the transforming growth factor-beta (TGF-beta) superfamily, is a multifunctional molecule with distinct abilities to induce bone formation. BMP2 has been identified to have eminent pharmaceutical importance for clinical application. We previously constructed stable cell line in Chinese hamster ovary cells (CHO) that highly expressed recombinant human BMP2 (rhBMP2). For large-scale production of the recombinant protein used in clinical application, it is critical to have both high expression and stability of the protein. In the present study, the stability of the cell line (rCHO(hBMP2)-C8) with the highest expression, as well as the stability of rhBMP2 protein were investigated systematically. We cultured the rCHO (hBMP2)-C8 cell line in the presence or absence of MTX for two months, the cell growth and rhBMP2 production characteristics were examined during the culture; we found the duration that the rCHO(hBMP2)-C8 cell line could secret rhBMP2 continually into the serum-free medium. Moreover, we detected the temperature sensitivity of rhBMP2 in culture medium. This study will contribute to our understanding for further producing rhBMP2 by large-scale culture technology.