EphA3 inhibits migration and invasion of esophageal cancer cells by activating the mesenchymal-epithelial transition process

Abstract

Eph receptor tyrosine kinases are critical for cell-cell communication during normal and oncogenic development. Eph receptor A3 (EphA3) expression is associated with tumor promotion in certain types of cancer; however, it acts as a tumor suppressor in others. The expression levels of EphA3 and its effects on tumor progression in esophageal squamous cell carcinoma (ESCC) cell lines were determined using reverse transcription-quantitative polymerase chain reaction analysis and a Transwell invasion assay. The present study demonstrated that EphA3 expression was decreased in ESCC tissues and cell lines. Treatment with the DNA methylation inhibitor 5-aza-2'-deoxycytidine increased the mRNA expression levels of EphA3 in the ESCC cell lines KYSE510 and KYSE30. In addition, overexpression of EphA3 in KYSE450 and KYSE510 cells inhibited cell migration and invasion. EphA3 overexpression also decreased RhoA GTPase. Furthermore, EphA3 overexpression induced mesenchymal-epithelial transition, as demonstrated by epithelial-like morphological alterations, increased expression of epithelial proteins (E-cadherin and the tight junction protein 1 zonula occludens-1) and decreased expression of mesenchymal proteins (Vimentin, N-cadherin and Snail). Conversely, silencing EphA3 in KYSE410 cells triggered epithelial-mesenchymal transition, and promoted cell migration and invasion. These results suggested that EphA3 may serve a tumor-suppressor role in ESCC.