LAUSR

OBJECTIVE Long-chain non-coding LOC554202, as a host gene for microRNA-31, has been shown to play a crucial role in a variety of diseases, especially tumors. However, its biological function in nasopharyngeal carcinoma (NPC) has not been reported. PATIENTS AND METHODS The expression levels of LOC554202 and microRNA-31 in NPC tumor tissue samples and cell lines were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The impacts of LOC554202 and microRNA-31 on the biological functions of NPC cells were examined by Cell Counting Kit-8 (CCK-8) and transwell assays. In addition, the modulation of LOC554202 on the expressions of microRNA-31 and RhoA was further confirmed by qRT-PCR and Western blot analysis. RESULTS The data of this study indicated that LOC554202 expression in NPC tissues and cell lines was remarkably upregulated, while microRNA-31 level showed an opposite tendency. Increasing LOC554202 expression remarkably enhanced the growth and metastasis of NPC cells, which was inhibited by overexpression of microRNA-31. Overexpression of LOC554202 downregulated microRNA-31 expression but upregulated that of RhoA, which may be a potential mechanism for the implication of LOC554202 in NPC. CONCLUSIONS As a host gene of microRNA-31, LOC554202 enhances RhoA expression and thus promotes the proliferative capacity and invasiveness of NPC cells.