Rabbit Anti-Human ERO1L Polyclonal Antibody

Autophagy is a process that degrades intracellular constituents, such as long-lived or damaged proteins and organelles, to buffer metabolic stress under starvation conditions. Deregulation of autophagy is involved in the progression of cancer. However, the predictive value of autophagy for breast cancer prognosis remains unclear. First, based on gene expression profiling, we found that autophagy genes were implicated in breast cancer. Then, using the Cox proportional hazard regression model, we detected autophagy prognostic signature for breast cancer in a training dataset. We identified a set of eight autophagy genes (BCL2, BIRC5, EIF4EBP1, ERO1L, FOS, GAPDH, ITPR1 and VEGFA) that were significantly associated with overall survival in breast cancer. The eight autophagy genes were assigned as a autophagy-related prognostic signature for breast cancer. Based on the autophagy-related signature, the training dataset GSE21653 could be classified into high-risk and low-risk subgroups with significantly different survival times (HR=2.72, 95% CI=(1.91, 3.87); P=1.37x10(-5)). Inactivation of autophagy was associated with shortened survival of breast cancer patients. The prognostic value of the autophagy-related signature was confirmed in the testing dataset GSE3494 (HR=2.12, 95% CI=(1.48, 3.03); P=1.65x10(-3)) and GSE7390 (HR=1.76, 95% CI=(1.22, 2.54); P=9.95x10(-4)). Further analysis revealed that the prognostic value of the autophagy signature was independent of known clinical prognostic factors, including age, tumor size, grade, estrogen receptor status, progesterone receptor status, ERBB2 status, lymph node status and TP53 mutation status. Finally, we demonstrated that the autophagy signature could also predict distant metastasis-free survival for breast cancer. (c) 2015 Wiley Periodicals, Inc.

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.