Heterologous expression of the lipid transfer protein CERT increases therapeutic protein productivity of mammalian cells

Improving the secretory capacity of Chinese hamster ovary cells by ectopic expression of effector genes: Lessons learned and future directions

“…In fact, multiple reactions within the biosynthetic pathway of MAb seem amenable for improvement (O'Callaghan et al, 2010). This notion is supported by non-limiting examples of studies demonstrating an increase in volumetric productivity or q p in CHO cells upon the expression of effector genes related to translation and translocation (Le Fourn et al, 2014), ER folding processes (Borth et al, 2005;Chung et al, 2004;Hwang et al, 2003) and protein transport and secretion (Florin et al, 2009;Peng et al, 2011;Peng and Fussenegger, 2009) (Fig. 1).…”

Phosphoregulation of the Ceramide Transport Protein CERT at Serine 315 in the Interaction with VAMP-associated Protein (VAP) for Inter-organelle Trafficking of Ceramide in Mammalian Cells

“…For example, the inhibition of CERT was shown to re-sensitize various types of drug-resistant cancer cells to anti-tumor drugs (33). The expression of a constitutively SRMdephosphorylated form of CERT (CERT S132A) resulted in the enhanced secretion of monoclonal antibodies in CHO cells (34). In addition, a dysfunction in CERT may be relevant to the palmitate-induced inhibition of insulin gene expression in islet ␤-cells (35).…”

Cell line‐specific control of recombinant monoclonal antibody production by CHO cells

“…The modeled qMab in each case was 46.3, 4.5, and 0.02 pg cell À1 day À1 , respectively. Secondly, as previous reports have highlighted the importance of specific cellular processes as being particularly rate limiting for Mab production, notably disulfide formation in the ER mediated by protein disulfide isomerase (Borth et al, 2005;Davis et al, 2000) and secretory vesicular trafficking (Florin et al, 2009;Peng and Fussenegger, 2009) we used the mathematical model to investigate the increase in qMab arising from a 100% increase in either (i) all folding and assembly reaction rate constants (K HC 2 , K HC 2 LC , K HC 2 LC 2 , and K LC 2 ; Table III) or (ii) all secretory rate constants (i.e., a decrease in t 1=2;ER , t 1=2;LC , t 1=2;LC 2 , and t 1=2;G ; Table III). As shown in Figure 7, increasing the rate constant for Mab assembly had a negligible effect on qMab of almost all cell lines, apart from cell line 164, which exhibits a specific limitation in this Response coefficients were derived from a 0.1% increase in HC/LC transcription rate, HC/LC translation rate, HC 2 LC 2 folding and HC 2 LC 2 secretion rates and from a 0.1% decrease in the rates of both HC/LC mRNA decay (i.e., a 0.1% increase in mRNA stability) and the rate of process.…”

“…Peng and Fussenegger (2009) engineered increased vesicle trafficking within CHO cells by overexpression of the Sec1/Munc18 proteins Sly1 and Munc18c, proteins that function to mediate vesicle fusion and trafficking. Most recently Florin et al (2009) have enhanced qMab in CHO cells by heterologous expression of a mutant form of CERT, a lipid transfer protein that is involved in regulating protein transport from the Golgi to the plasma membrane. Genetic engineering of secretion has the added benefits of not shifting bottlenecks further downstream in the Mab synthetic pathway or being protein product specific.…”