Erythropoietin-producing hepatocyte receptor type A2 (EphA2) is a
tyrosine kinase that binds to
ephrins (e.g., ephrin-A1) to initiate bidirectional signaling between cells. The binding of EphA2 and
ephrin-A1 leads to the inhibition of Ras-MAPK activity and
tumor growth. During
tumorigenesis, the normal interaction between EphA2 and
ephrin-A1 is hindered, which leads to the overexpression of EphA2 and induces
cancer. The overexpression of EphA2 has been identified as a notable
tumor marker in diagnosing and treating
pancreatic cancer. In this study, we used phage display to isolate specific
antibodies against the active site of EphA2 by using a discontinuous recombinant
epitope for immunization. The therapeutic efficacy and inhibition mechanism of the generated antibody against
pancreatic cancer was validated and clarified. The generated
antibodies were bound to the conformational
epitope of endogenous EphA2 on
cancer cells, thus inducing cellular endocytosis and causing EphA2 degradation. Molecule signals pAKT, pERK, pFAK, and pSTAT3 were weakened, inhibiting the proliferation and migration of
pancreatic cancer cells. The humanized antibody hSD5 could effectively inhibit the growth of the xenograft
pancreatic cancer tumor cells BxPc-3 and Mia PaCa-2 in mice, respectively. When antibody hSD5 was administered with
gemcitabine, significantly improved effects on
tumor growth inhibition were observed. Based on the efficacy of the
IgG hSD5
antibodies, clinical administration of the hSD5
antibodies is likely to suppress
tumors in patients with
pancreatic cancer and abnormal activation or overexpression of EphA2 signaling.