Selective endocytosis of recombinant human BMPs through cell surface heparan sulfate proteoglycans in CHO cells: BMP-2 and BMP-7

Cell surface heparan sulfate proteoglycan (HSPG)-mediated endocytosis results in poor yields of recombinant human bone morphogenetic proteins (rhBMPs) from CHO cell cultures. Upon incubation of rhBMP-2 and rhBMP-7 with CHO cells at 37 °C, both rhBMP-2 and rhBMP-7 bound to the cell surface HSPGs in CHO cells, but only rhBMP-2 was actively internalized into CHO cells. Cell surface HSPGs were found to serve as the main receptor for rhBMP-2 internalization. It was also found that the cell surface HSPG-mediated endocytosis of rhBMP-2 occurred through both the clathrin- and caveolin-dependent pathways. Blockage of rhBMP-2 internalization by the addition of structural analogs of HSPGs such as dextran sulfate (DS) and heparin dramatically increased rhBMP-2 production in recombinant CHO (rCHO) cell cultures. Compared to the control cultures, addition of DS (1.0 g/L) and heparin (0.2 g/L) resulted in a 22.0- and 19.0-fold increase in the maximum rhBMP-2 concentration, respectively. In contrast, the production of rhBMP-7, which was not internalized into the rCHO cells, did not dramatically increase upon addition of DS and heparin. Taken together, rhBMPs have a different fate in terms of HSPG-mediated internalization in CHO cells. HSPG-mediated endocytosis of each rhBMP should be understood individually to increase the rhBMP yield in rCHO cell cultures.

Development of a serum free medium for HUMIRA® biosimilar by design of experiment approaches

BackgroundSerum have been traditionally used to support growth of animal cell cultures. However, the increasing growth of therapeutic biopharmaceuticals market, accelerated the high demand for the serum-free medium (SFM).ObjectiveThe main objective is to design a SFM for a stable rCHO cell line that produces a fully anti-human TNF-α monoclonal antibody (mAb) corresponding to HUMIRA® biosimilar.Materials and methodsDesign of Experiment (DoE) approaches were used to determine the key factors due to their effect on specific growth rate and mAb production. The production was carried out in T-flasks at different initial cell concentrations and then in Erlenmeyers with the developed SFM. mAb production was compared with commercial SFMs in terms of yield and productivity.ResultsRegarding to our findings, when the developed SFM-adapted cells were compared with the cells produced in commercial SFMs, the mAb productivity in developed SFM were higher (1.3–1.6 times) depending on higher mAb concentration and less (3–5 times) cell concentration. Additionally, the produced mAb in the developed SFM provided high conformational similarity with its originator HUMIRA®.ConclusionDoE approaches could be used to reduce cost and time in designing SFM for any commercially important cell line to produce high value biologics.