A Novel lncRNA loc339803 acts as CeRNA of miR-30a-5p to promote the migration and invasion of hepatocellular carcinoma cells

Abstract Background Hepatocellular carcinoma (HCC) is one of the most common malignant tumors, and has an unfavorable clinical outcome. Emerging evidences have demonstrated that long noncoding RNAs (lncRNAs) play an important role in the carcinogenesis and progression of HCC. However, the clinical significances, the biological roles of most lncRNAs in HCC remain poorly understood. Methods The expression levels of lncRNA loc339803 in HCC tissues and cell lines were determined by quantitative real-time polymerase chain reaction(qRT-PCR) assay. The cellular sublocalization of loc339803 were determined by fluorescence in situ hybridization and nuclear & cytoplasmic RNA isolation assay. Western blot, CCK-8, Edu, colony formation, migration and invasion assays were used to investigate the roles of loc339803 in progression of HCC in vitro. A mouse model for lung metastasis was constructed to evaluate the role of loc339803 in HCC development in vivo. The correlations among loc339803, miR-30a-5p and SNAIL1 were validated by qRT-PCR and a dual- luciferase reporter assay. Results The expression of loc339803 was upregulated in HCC tissues and cell lines, and positively correlated with tumor size, advanced tumor stage, higher serum AFP level and poor prognosis of HCC patients. loc339803 can promote the migration and invasion of HCC cells in vivo and in vitro. Further studies demonstrated the loc339803 functioned as a competing endogenous RNA (ceRNA) by directly binding to miR-30a-5p, thus up-regulating the expression of snai1, a target gene of miR-30a-5p. Moreover, miR-30a-5p upregulation blocked the enhancement of migration and invasion of HCC cells induced by loc339803 overexpression. Conclusions Loc339803 may be oncogenic in HCC and associated with poor clinical outcomes. LncRNA loc339803 might promote the invasion and migration of HCC cells through regulating miR-30a-5p/ SNAIL1 axis.