lincRNA‐p21 inhibits invasion and metastasis of hepatocellular carcinoma through Notch signaling‐induced epithelial–mesenchymal transition

AIM: Emerging evidence has showed that long non-coding RNA (lncRNA) play an important role in the occurrence and development of various cancers. In the present study, the expression level of lincRNA-p21 was investigated in hepatocellular carcinoma (HCC), and its role in invasion of HCC was also explored. METHODS: The lincRNA-p21 levels in human HCC tumor tissue and cell lines HepG2 and SMMC-7721 were determined by real-time polymerase chain reaction. Transfected HCC cells with pcDNA-lincRNA-p21 or si-lincRNA-p21 for overexpression or downregulation of lincRNA-p21, the Notch signaling and epithelial-mesenchymal transition (EMT)-related proteins and cell invasion were measured by western blot and Transwell assay, respectively. A tumor xenotransplant mouse model was also established to investigate the role of lincRNA-p21 in tumor metastasis in vivo. RESULTS: The lincRNA-p21 expression was downregulated in HCC tissue and cells. Overexpression of lincRNA-p21 inhibited Notch singling and EMT, while its downregulation led to the reverse result. The invasion of HCC cell was also inhibited by pcDNA-lincRNA-p21, and activation of Notch signaling reversed this effect. In vivo, overexpression of lincRNA-p21 decreased the tumor metastasis, as well. CONCLUSION: lincRNA-p21 was downregulated in HCC and lincRNA-p21 overexpression contributed to the inhibition of tumor invasion through mediating Notch signaling induced EMT.