MicroRNA-155 expression and clinical value in hepatocellular carcinoma

Abstract

Objective To analyze the microRNA-155 (miR-155) expression in hepatocellular carcinoma (HCC), and to assess its correlation with clinicopathological parameters and its prognostic significance. Methods MiR-155 expression was detected in specimens of HCC and its adjacent non-tumorous li-ver tissues in 124 HCC patients by real-time PCR. The expression was also detected in different HCC cell lines. The Kaplan-Meier Curve was used to analyze survival of HCC patients. Gain- and loss-of-function studies were used to determine whether miR-155 impact cell cycle, cell proliferation and apoptosis of HCC cells. Results Expression of miR-155 in HCC tissues was significantly elevated when compared with that in the adjacent non-tumor liver tissues (P<0.05). MiR-155 expression was significantly higher in different HCC cell lines (P<0.05) than that in normal liver cells. MiR-155 overexpression was significantly correlated with large tumor size (P<0.05), high histological grade (P<0.05) and advanced tumor stage (P<0.05). Patients with high miR-155 expression had significantly decreased overall survival (P<0.05) and disease-free survival (P<0.05). Upregulation of miR-155 promoted cell cycle transition from G1 to S phase (P<0.05), increased cell proliferation (P<0.05) and apoptosis resistance (P<0.05) in Hep3B cells. Downregulation of miR-155 resulted in G1 arrest, apoptosis promotion and proliferation reduction in SMMC-7721 cells (P<0.05). Conclusion MiR-155 can be used as a prognostic marker for HCC patients, and target therapy on miR-155 can be used as a potential option to prevent HCC progression. Key words: MicroRNA-155; Hepatocellular carcinoma; Cell cycle; Cell proliferation; Apoptosis