Abstract
Because membrane type 1-matrix metalloproteinase 1 (MT1-MMP) and erythropoietin-producing hepatocellular receptor 2 (EphA2) expression are upregulated by the Ras/mitogen-activated protein kinase pathway, they are frequently coexpressed in malignant tumors. MT1-MMP cleaves the N-terminal ligand-binding domain of EphA2 and inactivates its ligand-dependent tumor-suppressing activity. Therefore, specific detection of the cleaved N-terminal EphA2 fragment in blood might be an effective biomarker to diagnose malignant tumors. To evaluate this possibility, we developed three monoclonal antibodies against the soluble EphA2 fragment. One of them recognized this fragment specifically, with negligible cross-reactivity to the intact form. We used the cleaved form-specific antibody to develop a quantitative enzyme-linked immunosorbent assay and confirmed the linear reactivity to the recombinant fragment. We applied this assay on commercially available serum specimens obtained from patients with several types of cancer including gastric, pancreatic, esophageal, gastroesophageal, and head-and-neck cancers, and healthy donors. Soluble EphA2 fragment levels in cancer-patient sera were higher than those in healthy donors (n=50). In particular, levels of eight out of nine (89%) pancreatic cancer patients and ten out of seventeen (59%) gastric cancer patients significantly exceeded cutoff values obtained from the healthy donors, whereas those of esophageal and head-and-neck cancer-patient sera were low. The preliminary receiver operating characteristic curve analysis for pancreatic cancer demonstrated that the sensitivity and specificity were 89.0% and 90.0%, respectively, whereas those of the conventional digestive tumor marker CA19-9 were 88.9% and 72.0%, respectively. These results indicated that specific detection of soluble EphA2 fragment levels in serum could be potentially useful as a biomarker to diagnose pancreatic cancer.
Highlights
Erythropoietin-producing hepatocellular receptor 2 (EphA2), a member of the mammalian Eph receptor kinase family, is expressed in epithelial cells and acts to suppress unscheduled growth signals for stabilization of the epithelial cell phenotype
Because overexpression of EphA2 is associated with disease progression and metastasis of cancer cells, and it is thought to be a possible target for cancer therapy,[3,4] small-molecule inhibitors, siRNAs, and neutralizing antibodies against EphA2 are currently under evaluation while leaving the possibility of EphA2 as a tumor suppressor
We developed monoclonal antibodies against the soluble EphA2 fragment released from cancer cells by MT1-matrix metalloproteinases (MMPs) cleavage
Summary
Erythropoietin-producing hepatocellular receptor 2 (EphA2), a member of the mammalian Eph receptor kinase family, is expressed in epithelial cells and acts to suppress unscheduled growth signals for stabilization of the epithelial cell phenotype. We developed monoclonal antibodies (mAbs) against the soluble EphA2 fragment released from cancer cells by MT1-MMP cleavage. The four recombinant EphA2 fragments (Figure 1a, antigens #1–4) were subjected to SDS-PAGE under reducing or non-reducing conditions and were analyzed with western blot analysis (Supplementary Figure S1).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
