miR-940 inhibits cell proliferation and promotes apoptosis in esophageal squamous cell carcinoma cells and is associated with post-operative prognosis

The present study aimed to examine microRNA (miR)-940 expression in esophageal squamous cell carcinoma (ESCC) tissues and cells, analyze its association with the clinicopathological features and prognosis of patients, and explore the potential underlying mechanisms. miR-940 expression in ESCC cell lines and a normal esophageal cell line was detected using reverse transcription-quantitative (RT-q)PCR. Furthermore, 210 resected ESCC tissue and para-carcinoma tissue specimens were collected, and miR-940 expression in those tissues was detected by RT-qPCR. In addition, the association of miR-940 with the clinicopathological features and prognosis of patients was analyzed. In an in vitro experiment, miR-940 mimics were transduced into ESCC cells by the liposome method. An MTT assay was used to detect the effect of miR-940 on the viability of ESCC cells. The influence of miR-940 on the cell cycle and apoptotic rate of ESCC cells was detected by flow cytometry. The present results indicated that the expression levels of miR-940 in human ESCC tissues and cell lines were markedly downregulated, and that low expression of miR-940 in ESCC tissues was significantly associated with a poor degree of differentiation, positive lymph node metastasis and advanced clinical stage. Kaplan-Meier survival analysis suggested that low miR-940 expression was associated with poor prognosis. Cox regression analysis revealed that lymph node metastasis, clinical stage and miR-940 expression were independent risk factors affecting the prognosis of patients. Overexpression of miR-940 in ESCC cells markedly reduced the cell viability, blocked the cell cycle at G0/G1 phase and promoted cell apoptosis. These results suggest that miR-940 is downregulated in ESCC, which is linked to the occurrence and progression of ESCC. Conversely, overexpression of miR-940 reduced the cell viability and promoted apoptosis of ESCC cells. Therefore, miR-940 may be a promising novel prognostic marker and anti-cancer target in ESCC.