Effect of Bcl-xL overexpression on erythropoietin production in recombinant Chinese hamster ovary cells treated with dimethyl sulfoxide

Abstract Dimethyl sulfoxide (DMSO) can increase the specific productivity ( q ) of foreign proteins in mammalian cells, while it can also induce cell death, particularly apoptosis. Bcl-xL is a typical anti-apoptotic protein that inhibits the apoptosis in recombinant Chinese hamster ovary (rCHO) cell culture. To evaluate the potential role of Bcl-xL overexpression on DMSO-mediated erythropoietin (EPO) production, we used EPO-producing rCHO cells with regulated Bcl-xL overexpression (EPO-off-Bcl-xL) by doxycycline. Although DMSO addition enhanced specific EPO productivity ( q EPO ), it also induced cell death in EPO-off-Bcl-xL cells. Bcl-xL overexpression reduced the DMSO-induced cell death followed by release of various enzymes from plasma membrane-damaged cells as evidenced from LDH assay, resulting in delayed loss of EPO. However, it did not significantly improve the maximum EPO production. In addition, Bcl-xL overexpression suppressed DMSO-induced apoptosis, characterized by DNA fragmentation and Annexin V staining. Taken together, Bcl-xL overexpression could inhibit DMSO-induced apoptosis, thereby delaying the loss of EPO.