EphA2­enriched exosomes promote cell migration and are a potential diagnostic serum marker in pancreatic cancer.

Pancreatic cancer (PC) is the fourth most common cause of cancer­related mortality worldwide and is characterized by high invasiveness and early metastasis. To identify novel diagnostic markers, the present study aimed to understand the mechanism underlying PC progression. The present study demonstrated that exosomes derived from the highly metastatic Panc­1 PC cell line were internalized by a low metastatic cell line, resulting in increased migration of the latter. Proteomics analysis further revealed that the receptor tyrosine kinase Eph receptor A2 (EphA2) was overexpressed in the Panc­1 exosomes, and these Exo_EphA2 had the ability to transfer metastatic potential to recipient cells. Consistent with this, circulating Exo_EphA2 levels were higher in patients with PC compared with healthy controls. Taken together, these results indicated that Exo_EphA2 acts an oncogene in PC and is a potential tumor maker for PC diagnosis.

Clinical implications of the plasma EphA2 receptor level in critically ill patients with septic shock.

The Eph/ephrin receptor ligand system is known to play a role in inflammation induced by infection, injury, and inflammatory diseases. The present study aimed to evaluate plasma EphA2 receptor levels in critically ill patients with sepsis. This study was a prospective cohort study evaluating samples and clinical data from the medical intensive care unit (MICU) of a 2000-bed university tertiary referral hospital in South Korea. Positive correlations of the plasma EphA2 receptor level with the acute physiology and chronic health evaluation (APACHE) II score and the sequential organ failure assessment (SOFA) score were observed. The area under the curve (AUC) for the plasma EphA2 receptor level on a receiver operating characteristic curve was 0.690 (95% confidence interval [CI], 0.608-0.764); the AUCs for the APACHE II score and SOFA scores were 0.659 (95% CI, 0.576-0.736) and 0.745 (95% CI, 0.666-0.814), respectively. A Cox proportional hazard model identified an association between an increased plasma EphA2 receptor level (>51.5 pg mL-1) and increased risk of 28-day mortality in the MICU (hazard ratio = 3.22, 95% CI, 1.709-6.049). An increased plasma EphA2 receptor level was associated with sepsis severity and 28-day mortality among sepsis patients.

Specific detection of soluble EphA2 fragments in blood as a new biomarker for pancreatic cancer.

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.

Diagnostic and prognostic value of tissue and circulating levels of Ephrin-A2 in prostate cancer.

Ephrin-A2, a member of the Eph/ephrin family, is associated with tumorigenesis and tumor progression. This study aimed to assess the diagnostic and prognostic value of both serum and tissue levels of Ephrin-A2 in prostate cancer (PCa) management. One hundred and forty-five frozen prostate tissues, 55 paraffin-embedded prostate tissues, 88 serum samples, and seven prostate cell lines (RWPE-1, LNCaP, LNCaP-LN3, PC-3, PC-3M, PC-3M-LN4, and DU145) were examined via quantitative reverse transcription-PCR (qRT-PCR), immunohistochemistry, enzyme-linked immunosorbent assay, and western blotting. Induced Ephrin-A2 messenger RNA (mRNA) or protein expression was detected in 8.6 % (5/58) benign prostatic hyperplasia (BPH), 59.8 % (52/87) PCa, and five prostate cancer cell lines. Ephrin-A2 immunostaining was present in 6.7 % (1/15) patients with BPHs and 62.5 % (25/40) clinically localized PCa. Accordingly, serum Ephrin-A2 was significantly higher in PCa patients compared to those in the BPH patients and controls (P < 0.001). The expression of Ephrin-A2 was higher in tumor patients with an elevated Gleason score or T3-T4 staging. Ephrin-A2 expression was correlated with Ki-67 expression in PCa patients, both at the gene scale and protein level. Our data indicate that Ephrin-A2 is a potential diagnostic and prognostic biomarker and a promising molecular therapeutic target to attenuate prostate cancer progression.