ERO1L Promotes Hepatic Metastasis through Activating Epithelial-Mesenchymal Transition (EMT) in Pancreatic Cancer

Biological mechanisms and clinical significance of endoplasmic reticulum oxidoreductase 1 alpha (ERO1α) in human cancer

A firm link between endoplasmic reticulum (ER) stress and tumors has been wildly reported. Endoplasmic reticulum oxidoreductase 1 alpha (ERO1α), an ER-resident thiol oxidoreductase, is confirmed to be highly upregulated in various cancer types and associated with a significantly worse prognosis. Of importance, under ER stress, the functional interplay of ERO1α/PDI axis plays a pivotal role to orchestrate proper protein folding and other key processes. Multiple lines of evidence propose ERO1α as an attractive potential target for cancer treatment. However, the unavailability of specific inhibitor for ERO1α, its molecular inter-relatedness with closely related paralog ERO1β and the tightly regulated processes with other members of flavoenzyme family of enzymes, raises several concerns about its clinical translation. Herein, we have provided a detailed description of ERO1α in human cancers and its vulnerability towards the aforementioned concerns. Besides, we have discussed a few key considerations that may improve our understanding about ERO1α in tumors.

Cordycepin reprogramming lipid metabolism to block metastasis and EMT via ERO1A/mTOR/SREBP1 axis in cholangiocarcinoma

Cholangiocarcinoma (CCA) with a high malignancy is usually diagnosed as advanced and is prone to metastasis and leads to a poor prognosis. It is reported that cordycepin has anti-tumor effect. However, the molecular targets and mechanisms of cordycepin in inhibiting CCA metastasis remains unclear. In order to evaluate the therapeutic effect of cordycepin on CCA metastasis, experiments were conducted in vivo and in vitro. The results showed that cordycepin inhibited the migration and EMT progression of HuCCT1 and QBC939 cells. Cordycepin has a strong hypolipidemic effects, therefore, we examined its effect on lipid metabolism in CCA. Cordycepin inhibits SREBP1 mediated fatty acid synthesis through the AKT/mTOR signaling pathway. Meanwhile, cordycepin can reduce ERO1A expression in HuCCT1 and QBC939 cells. ERO1A plays a role in malignant tumors. ERO1A promotes migration and lipid metabolism of CCA cells through AKT/mTOR signaling pathway. In addition, cordycepin significantly inhibited the tumor metastasis and the serum levels of TG and T-CHO in mice. Taken together, we demonstrate that cordycepin mediated ERO1A/mTOR/SREBP1 axis inhibits lipid metabolism and metastasis in CCA cells in vitro and in vivo. These data suggest that cordycepin can be used as a novel drug for the clinical treatment of CCA and to improve the prognosis.

Role of Ero1α in cognitive impairment induced by chronic hypoxia

Recent reports suggested the endoplasmic reticulum stress (ERS)-associated pathway is involved with cognitive impairment in hypoxia condition. ERO1-like protein alpha (Ero1α), an endoplasmic reticulum membrane-bound N-glycoprotein, has been reported to promote oxidative protein folding. However, no studies have reported whether the Ero1α is trapped in hypoxia-induced neuronal loss through the ERS-associated pathways. In our study, this effect of Ero1α was investigated using C57BL/6J mice, the HT22 cells and primary rat neurons. C57BL/6J mice were modeled in a hypoxic chamber for 4 weeks. Behavioral tests were then carried out to test cognitive functions, including the Morris water maze and fear conditioning test. Proteomics showed that Ero1α distinctly upregulated compared with normoxia group and verified using western blotting. Flow cytometry and immunofluorescence were used to analyze the neuroprotective effect of inhibitor EN460 of Ero1α in the HT22 cells. In C57BL/6J mice, hypoxia significantly caused cognitive decline. Brain slice staining results were also used to confirm this effect. Western blot analysis demonstrated that Ero1α, ERS-associated proteins and apoptosis-associated proteins significantly increased in the hypoxia treated groups, further proliferation-related marker protein decreased. EN460, a selective endoplasmic reticulum oxidation 1 (ERO1) inhibitor, counteracted neuronal apoptosis and ameliorated neuronal cell proliferation in the HT22 cells. Taken together, our data indicate that hypoxia induces cognitive impairment, at least in part, by upregulating Ero1α which contributes to neuronal apoptosis through ERS signaling pathway, providing preliminary experimental evidence that the Ero1α is a promising therapeutic target in hypoxia-induced cognitive deficits.