[The expression and significance of miR-33b and HMGA2 in esophageal squamous cell carcinoma].

Objective To investigate the expression and significance of miR-33b and high mobility group AT-hook 2 (HMGA2) in esophageal squamous cell carcinoma (ESCC). Methods Real-time quantitative PCR (qRT-PCR) was used to detect the expression levels of miR-33b and HMGA2 mRNA from the ESCC and adjacent tissues. Immunohistochemical SP method was performed to test the protein level of HMGA2. After the miR-33b mimics, inhibitor and controls were separately transfected into TE-1 and Eca-109 cells, the expression levels of miR-33b and HMGA2 in each group were again determined by qRT-PCR and Western blotting. Results The expression level of miR-33b from the ESCC tissues of 40 cases were significantly lower than that from the adjacent normal tissues. However, the expression level of HMGA2 protein from the ESCC tissues were significantly higher than that from the adjacent normal tissues. The expression level of miR-33b in the HMGA2 positive group was lower than that in the HMGA2 negative group. The correlation analysis showed that the expression of miR-33b was negatively correlated with the mRNA expression of HMGA2 in the ESCC tissues. There were no significant difference in the mRNA expression of HMGA2 among the cells transfected separately with miR-33b mimics, inhibitor and controls, but Western blotting indicated that the protein expression of HMGA2 decreased significantly in the miR-33b over-expressed cells. Conclusion The expression of miR-33b decreases and HMGA2 increases in the ESCC tissues. The over-expression of miR-33b could suppress the protein expression of HMGA2 in the esophageal cancer cells, but the mRNA expression of HMGA2 would not be affected, which suggests that miR-33b might regulate the protein expression of HMGA2 in the post-transcriptional level.