Anti-ERO1L monoclonal antibody, clone FQS23585

The abnormal secretion of CA125, a classic tumor marker, is usually related to a poor prognosis in various tumors. Thus, this study aimed to explore the potential mechanisms that promote CA125 secretion in lung cancer. By querying the database, the gene endoplasmic reticulum oxidoreductase 1L (ERO1L) was identified and chosen as the research subject. The antibody chips were used to screen the lung cancer cell supernatant and found that the most obvious secreted protein was CA125. ERO1L was found to promote the secretion of IL6R by affecting the formation of disulfide bonds. IL6R bound to IL6 and triggered the activation of the NF-kappa B signaling pathway. Then, NF-kappa B bound to the promoter of MUC16, resulting in overexpression of MUC16. The extracellular segment of MUC16 was cleaved to form CA125, while the C terminus of MUC16 promoted the EMT phenotype and the release of IL6, forming a positive feedback pathway. In conclusion, ERO1L might affect the secretion of CA125 through the IL6 signaling pathway and form a positive feedback loop to further promote the development of lung cancer. This might expand the application scope of CA125 in lung cancer.

To enhance specific antibody (Ab) productivity (q(Ab)) of recombinant Chinese hamster ovary (rCHO) cells, post-translational limitations in the endoplasmic reticulum during antibody production should be relieved. Previously, we reported that overexpression of protein disulfide isomerase (PDI), which catalyzes disulfide bond exchanges and assists in protein folding of newly synthesized proteins, enhanced q(Ab) of rCHO cells by about 27% (Mohan et al., 2007, Biotechnol Bioeng 98:611-615). Since the rate limiting step in disulfide bond formation is found to be the regeneration of oxidized PDI, the oxidation state of PDI, as well as the amount of PDI, might be important. Endoplasmic reticulum oxidoreductase (ERO1L) maintains PDI in an oxidized state so that disulfide bond formation occurs. Here, PDI and its helper protein, ERO1L were overexpressed in rCHO cells producing an Ab in an attempt to case the bottleneck in disulfide bond formation, and hence, Ab folding and secretion. Transient expression of ERO1L alone and with PDI resulted in enhanced q(Ab), by 37% and 55%, respectively. In contrast, under stable inducible co-overexpression of PDI and ERO1L, the q(Ab) was unaffected or negatively affected by varying degrees, depending on the individual expression levels of these genes. In stable clones with altered oxidation state of PDI due to co-overexpression of PDI and ERO1L, secretion of Ab was hindered and PDI associated retention of Ab was seen in the Cells. Under transient gene expression, secretion of Ab was not compromised. The data presented here suggests a possible mechanism of PDI/ERO1L interaction with the target Ab and shows how the expression levels of these proteins could affect the q(Ab) of this Ab-producing rCHO cell line. Biotechnol. Bioeng. 2010;107: 337-346. (c) 2010 Wiley Periodicals, Inc.