Downregulation of MicroRNA-551b Correlates With Dissemination of Human Oral Squamous Cell Carcinoma

Abstract

Altered expression of microRNAs contributes to invasion and metastasis of many human cancers; however, the importance of microRNAs in head and neck cancers remains to be elucidated. In this study, we examined whether altered microRNA (miR)-551b expression correlated with invasive phenotypes of human oral squamous cell carcinoma (OSCC) invivo and invitro. Real-time polymerase chain reaction was used to detect the expression level of miR-551b in 71 OSCC tissues with lymph node metastasis and 50 nonmetastatic OSCC tissues. We also constructed miR-551b mimic-transfected cell lines HN4 and HN12. The effects of overexpressing miR-551b on the proliferation, migration, and invasion of OSCC cells were examined using Cell Counting Kit 8 (Dojindo, Kumamoto, Japan), plate clone formation, wound healing, and Transwell invasion experiments (Corning, Corning, NY).The association between clinical pathologic parameters and the expression level of miR-551b was analyzed using Kaplan-Meier survival analysis. The expression of miR-551b measured 0.33±0.11 in the 71 OSCC tissues with lymph node metastasis versus 0.54±0.06 in the 50 tissues with non-lymph node metastasis (P=.021).Regarding OSCC patients, the expression of miR-551b negatively correlated with patients' overall survival (P=.035). The ectopic expression of miR-551b inhibited the invasion and migration of OSCC cells. This is the first report showing that reduced miR-551b expression may be an event leading to OSCC invasion and metastasis.