Decreased Expression of MIR-134 and its Clinical Significance in Human Colorectal Cancer.

Dysregulation of miRNA is always associated with cancer development and progression. Aberrant expression of miR-134 has been found in some types of cancer. However, miR-134 expression and its clinical significance in colorectal cancer (CRC) have not been explored. The aim of this study was to explore the effects of miR-134 in CRC tumorigenesis and development.Quantitative RT-PCR was performed to evaluate miR-134 levels in CRC cell lines and 168 pairs of CRC specimens and adjacent noncancerous tissues. The association of miR-134 expression with clinicopathological factors and prognosis was also analyzed. Further, the effects of miR-134 on the biological behavior of CRC cells were investigated.MiR-134 expression was significantly downregulated in CRC cancer tissues and cell lines. Decreased miR-134 expression was significantly associated with large tumor size, positive lymph node metastasis, and advanced clinical stage Low miR-134 expression in CRC was an independent predictor of poor survival. Moreover, over-expression of miR-134 inhibited SW620 cell proliferation, invasion, and migration, and promoted cell apoptosis in vitro.These findings indicate that miR 134 may act as a tumor suppressor in CRC and would serve as a novel therapeutic agent for miR-based therapy.