Abstract
Oesophageal squamous cell carcinoma (ESCC) is a common and aggressive malignancy. Although many molecular alterations have been observed in ESCC, the mechanisms underlying the development and progression of this disease remain unclear. In the present study, miR-1224-5p was identified to be downregulated in ESCC tissues compared to normal tissues, and its low expression was correlated with shorter survival time in patients. In vitro experiments showed that miR-1224-5p inhibited the proliferation, colony formation, migration and invasion of ESCC cells. Mechanistic investigation revealed that miR-1224-5p directly targeted TNS4 and inhibited its expression, which led to the inactivation of EGFR-EFNA1/EPHA2-VEGFA (vascular endothelial growth factor A) signalling. Experiments in vivo confirmed the suppressive effect of miR-1224-5p on oesophageal cancer cells. By immunohistochemistry analysis of ESCC specimens, we found that TNS4 expression was positively correlated with that of VEGFA, and was significantly associated with lymph node metastasis and shorter survival time in patients. Together, our data suggest that miR-1224-5p downregulation is a frequent alteration in ESCC that promotes cell proliferation, migration, invasion and tumour growth by activating the EGFR-EFNA1/EPHA2-VEGFA signalling pathway via inhibition of TNS4 expression. Decreased miR-1224-5p and elevated TNS4 are unfavourable prognostic factors for ESCC patients.