Objective To study the expression levels of tumor suppressor gene RIKP and miRNA224 in esophageal squamous cell carcinoma (ESCC) tissues. To determine whether miRNA224 targets RKIP and the methylation status of miRNA224 gene promoter region in esophageal carcinoma. Methods The expression levels of RKIP and miRNA224 in ESCC and normal tissue were detected by using immunohistochemistry and real-time qPCR, respectively. Luciferase assay was used to determine the targeting of miRNA224 to RKIP. The methylation status of miRNA224 promoter region was studied by bisulfite sequencing PCR (BSP). Results In 40 cases of ESCC, RKIP expression was significantly lower than that of normal tissue; miRNA224 expression was higher in ESCC than in paracancerous tissue. Luciferase assay showed that miRNA224 targets RKIP 3′UTR thus inhibit its expression. The miRNA224 gene promoter region was hypomethylated in ESCC. Conclusion Compared with normal tissue, in ESCC, RKIP was downregulated, while miRNA224 was upregulated, and the promoter region of miRNA224 gene was hypomethylated. RKIP is the target of miRNA224, which may be closely related to esophageal squamous cell carcinoma.
