S117: Role of nutrient availability and Bcl-2Δ over-expression in controlling lactate accumulation by CHO cell cultures

Incorporating apoptotic resistance into production cell lines holds remarkable potential for several industrial applications, especially that of monoclonal antibody (mAb) production.  However, the associated impacts on cellular metabolism are only beginning to be understood, especially in regards to how anti-apoptotic proteins regulate lactate production and mitochondrial metabolism.  We are therefore investigating the global metabolic reprogramming that takes place in Chinese Hamster Ovary (CHO) cells that have been engineered to over-express the anti-apoptotic BcL-2Δ protein.  Our previous work has shown that limiting glutamine availability can have profound impacts on growth and lactate accumulation in CHO cell cultures. Specifically, when initial glutamine concentration was halved, the outgoing lactate flux was reduced by more than 50% while growth rate was increased by roughly 30%. When over-expressing BcL-2D, outgoing lactate flux and incoming glucose flux were reduced by roughly 40%, and the IVCD over the life of the culture was increased by over 30%. We are currently applying ¹³C metabolic flux analysis (MFA) to investigate how Bcl-2D interacts with glucose and glutamine availability to control metabolic fluxes in CHO cell cultures.  Our goal is to generate comprehensive flux maps that depict the flow of carbon through central metabolism under conditions of varying glucose and glutamine availability to demonstrate the impact of Bcl-2Δ over-expression.  We will present our current view of how nutrient availability and anti-apoptotic proteins interact to control lactate production and central metabolic fluxes in CHO cells.