[Effect of miR-146a on biological behavior of esophageal squamous cell carcinoma cells and its mechanism].

Abstract

Objective: To investigate the effects and mechanisms of miR-146a on the proliferation, invasion, migration, apoptosis and cell cycle of esophageal squamous cell carcinoma cells. Methods: The expressions of miR-146a in 3 esophageal squamous carcinoma cell lines (Eca109, KYSE140, KYSE150) were detected by real-time quantitative polymerase chain reaction (RT-qPCR). MiR-146a mimics was transfected into Eca109 to up-regulate the expression of miR-146a. Effects of miR-146a on cell proliferation, invasion and migration were evaluated by cell counting kit 8 (CCK-8), Transwell assay and wound-healing assay, respectively. The cell apoptosis and cycle were assessed by flow cytometry (FCM). Finally, relevant bioinformatics techniques were used to predict the target gene of miR-146a. Dual luciferase reporter assay was used to identify the interaction of 3' terminal untranslated region (3' UTR) of miR-146a and its target gene, interleukin-1 receptor-associated kinase (IRAK1). RT-qPCR and western blot were used to detect the mRNA and protein expressions of IRAK1, respectively. Results: The relative expressions of miR-146a in 3 esophageal squamous cell carcinoma cells (Eca109, KYSE140, KYSE150) were 0.36±0.05, 0.16±0.06 and 0.09±0.02, respectively, all of which were significantly lower than 1±0.05 of normal esophageal epithelial cells (HEEC) (P<0.01). The model of esophageal squamous cell carcinoma cells was constructed by transfecting miR-146a mimics into Eca109 cells. The results showed that the ability of absorbance value, the number of transmembrane cells (52±18), the reduced scratch distances at 48 hours and 72 hours after transfection [(25.29±0.77) μm, (30.66±0.91) μm] were significantly lower than those of the negative control group and blank control group (all P<0.01). The early apoptosis rate was (6.13±0.91)%, higher than (2.50±0.68)% of the negative control group (P<0.01) and (1.70±0.20)% of blank control group (P<0.01). The percentage of cells in G(1) phase [(44.74±6.76)%] was decreased while the G(2)/M phase [(41.88±2.88)%] was increased when compared with the negative control group and the blank control group (P<0.05 and P<0.01, respectively). The results of dual luciferase reporter gene assay showed that luciferase activity in the group co-transfected with IRAK1-wild-type and miR-146a mimics was significantly lower than that in the control groups (P<0.01). The results of RT-qPCR and western blot showed that the mRNA and protein expressions of IRAK1 in the co-transfected group were 1.02±0.28 and 1.00±0.05, respectively, both lower than those in the negative control group and the blank control group (P<0.01). Conclusions: The expressions of miR-146a are decreased in the esophageal squamous cell lines, which plays a role as tumor suppressor gene. MiR-146a can inhibit the proliferation, invasion and migration of esophageal squamous cell cells, promote apoptosis, and block the cell cycle at G(2)/M stage. MiR-146a may mediate the malignant biological behavior of esophageal cancer cells through the regulation of IRAK1.