Expression of the Mouse HSP27 Chaperone in CHO-K1 Cells for the Enhancement of Viable Cell Density in Batch Culture

Chinese hamster ovary (CHO) cells are extremely vulnerable to cell viability loss in culture despite the availability of different nutrients supplementation strategies. As a result, extending the culture lifetime can profoundly increase recombinant protein expression. Overexpression of HSP27 and its anti-apoptotic effects have been shown in human cell lines in previous studies. In the current study, mouse HSP27 (mHSP27) was cloned in pcDNA 3.1 hygro expression vector and was expressed in CHO-K1 cells to assess its impacts on cell viability and growth. Expression of mHSP27 in CHO-K1 cells was confirmed using RT-PCR. A 3-fold enhancement in peak viable cell density of mHSP27 transfected clones was observed, and culture viability loss was delayed by 2 days compared to un-transfected cells. In future studies, the resulting mHSP27 CHO-K1 cells could be employed as a novel host system for the transient and stable expression of therapeutic recombinant proteins.