miR-29b inhibits the progression of esophageal squamous cell carcinoma by targeting MMP-2.

Accumulating evidence has shown that microRNAs (miRNAs) are aberrantly expressed in human esophageal cancer and crucial to tumorigenesis. Herein, we identified the role of miR-29b in esophageal squamous cell carcinoma (ESCC) development in vitro and in vivo. MiR-29b expression was investigated in thirty cases of ESCC samples as well as four ESCC cell lines by real-time PCR. Transwell assays were conducted to explore the effects of miR-29b on the invasion of human ESCC cell lines. The impact of overexpression of miR-29b on putative target MMP-2 were subsequently confirmed via Western blot. Our results indicated that MiR-29b expression was frequently down-regulated in ESCC specimens and cell lines compared with adjacent normal tissues (p<0.05). Overexpression of miR-29b suppressed (p<0.05) ESCC cell invasion, as well as the growth of xenograft tumors in mice. Overexpression of miR-29b significantly decreased (p<0.05) the protein level of MMP-2, which has previously been identified as a direct target of miR-29b. Thus, our study demonstrated that overexpression of miR-29b inhibits tumor growth in part by targeting MMP-2. Our findings revealed that miR-29b may act as a tumor suppressor in ESCC, whose dysregulation may be involved in the initiation and development of human ESCC.