The present study aimed to investigate whether microRNA (miR)-490-3p can regulate MAPK1 expression, increase proliferation of esophageal squamous cell carcinoma (ESCC) and reduce ESCC cell apoptosis. The Cancer Genome Atlas (TCGA) database was used to explore the functional role of miR-490-3p in ESCC. The expression of miR-490-3p in ESCC tissues and adjacent tissues of patients with ESCC were detected by reverse transcription-quantitative PCR. The effect of miR-490-3p on ESCC cell proliferation and apoptosis were detected by cell counting kit-8 and clone formation assay, and flow cytometry, respectively. The dual luciferase reporter assay was used for detect the regulatory association between miR-490-3p and MAPK1. The TCGA dataset demonstrated that miR-490-3p expression was reduced in ESCC tissues compared with normal tissue. The expression of miR-490-3p was also lower in ESCC tissues compared with adjacent tissues. The expression of miR-490-3p in patients with stage III and IV ESCC were significantly lower than those in stage I and II. In patients with tumor >3 cm, miR-490-3p expression was lower than in patients with tumor <3 cm. Gene set enrichment analysis demonstrated that miR-490-3p may essentially regulate cell apoptosis. In addition, miR-490-3p depletion in TE1 and ECA109 cell lines promoted cell proliferation and inhibited cell apoptosis. The results from dual luciferase reporter assay demonstrated that miR-490-3p may be able to degrade MAPK1. Furthermore, MAPK1 overexpression in TE1 and ECA109 cells partially reversed the effects of miR-490-3p on cell proliferation and apoptosis. Low expression of miR-490-3p may therefore promote the proliferation and inhibit the apoptosis of ESCC cells by regulating MAPK1.

The methylation and expression of RECK, P53 and RUNX genes in patients with esophageal cancer was investigated. In order to achieve this aim, a sample of 58 patients with esophageal cancer, treated between February 2013 and February 2014, were considered as the observation group. Additionally, a sample of 42 healthy individuals was selected as the control group. Methylation status of RECK, P53 and RUNX genes from the observation and control groups were detected by MSP. Reverse transcriptase-quantitative PCR (RT-qPCR), enzyme-linked immunosorbent assay (ELISA), western blot and immunohistochemistry were used to detect the mRNA and protein levels of RECK, P53 and RUNX in both the observation and the control groups. Results showed that the methylation rates of RECK, P53 and RUNX genes in patients with esophageal cancer were 72.4% (42/58), 1.7% (1/58) and 3.4% (2/58), respectively, which were significantly different from those in the control group [7.1% (3/42), 90.5 (38/42), and 83.3% (35/42), respectively]. The mRNA expression level of RECK is only equal to the 2.3% of that in the control group, while the mRNA expression levels of P53 and RUNX were 65.1 and 47.2 times higher than those in the control group, respectively (p<0.05). ELISA showed that RECK protein level in the observation group (0.12±0.05) µg/l, was significantly lower than the control group (3.46±0.08) µg/l (p<0.05), while, P53 and RUNX protein levels in observation group were significantly higher than that in healthy people (6.43±0.12 µg/l vs. 0.64±0.06 µg/l and 4.32±0.14 µg/l vs. 0.53±0.09 µg/l, respectively), and the results were similar to western blot. The data of immunohistochemistry showed that the proportion of RECK protein positive cells in the observation group was significantly lower than that in the control group (9.5 vs. 82.3%, P<0.05), while the proportions of P53 and RUNX protein positive cell in the observation group were significantly higher than those in the control group (78.4 vs. 11.1% and 87.3 vs. 9.06%), respectively, (P<0.05). This study concluded that, in patients with esophageal cancer, the methylation of RECK gene is increased and the expression of RECK gene is inhibited, while methylation of RUNX gene decreased and their expression was increased. This change in methylation of these genes may promote the occurrence and development of esophageal cancer.