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

Purpose: 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) in vivo and in vitro. Materials and Methods: 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. Results: 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. Conclusions: This is the first report showing that reduced miR-551b expression may be an event leading to OSCC invasion and metastasis. (C) 2020 The Authors. Published by Elsevier Inc. on behalf of the American Association of Oral and Maxillofacial Surgeons.