Effects of dextran sulfate on cell growth and aggregation in CHO cell cultures

초록

Chinese hamster ovary (CHO) cells are mainly used for the production of various therapeutic proteins. Although they have been adapted in suspension cultures, their origin is anchorage-dependent. For that reason, the cells have a tendency to adhere each other and form aggregates. Cell aggregation is known to be related to cell adhesion molecules and extracellular matrix (ECM) [1]. Formation of aggregates are harmful to the cells in suspension cultures by inhibiting the transfer of oxygen and nutrients. It also reduces cell proliferation and induces cell death [2]. This causes negative impacts on productivity and makes products heterogeneous. Dextran sulfate (DS), a polyanion, is used as a dispersing agent in cell cultures [2]. In this study, we added DS to break the cell aggregates. Maximum viable cell density with DS was 1.2-fold higher than that of control. Viability was improved due to anti-apoptotic effects of DS. Aggregation rate was reduced by 38% with the addition of 250 mg/L DS. In addition, we investigated the effect of calcium concentration in culture medium and the level of gene expression related to ECM/adhesion pathway was analyzed to understand the mechanism of DS in reducing cell aggregates. As a result, it was found that the supplement of DS not only enhanced cell growth and viability but also inhibited cell aggregation.