Micro-RNA-181a regulates osteopontin-dependent metastatic function in hepatocellular cancer cell lines

Background. Osteopontin (OPN) is a variably expressed, secreted glycophosphoprotein that mediates the growth and metastases of hepatocellular cancer (HCC). MicroRNAs (miRNAs) may be responsible for variant OPN expression, interrupting translation by binding OPN messenger RNA (mRNA) in 3'-untranslated regions (UTRs) Methods. A microarray analysis identified mRNAs of interest Plasmid constructs using a luciferase reporter with variable OPN 3'UTR mutations were transfected into 2 HCC cell lines to determine miRNA regulation of OPN expression Western blot analyses confirmed variable OPN expression in. both cell lines. Invasion, adhesion, and migration evaluated metastatic behavior in Hep G2 mid Hep 313 with modified miRNA and OPN expression Results. Hap 3B produces 36 x mRNA 181a compared with Hep G2 Luciferase activity after transfection with miRNA 181a precursor was decreased in both cell lines (P <.01); luociferase activity increased with miRNA 181a inhibitor transfection in both cell lines (P <.01) Hep 313 transfected with mutated OPN 3'UTR increased luciferase activity 108% (P < 01) Hep G2 transfected with miRNA precursor decreased OPN expression 5 X (P <.01)111 Western blot analyses Hep 313 liwnsfixtion with miRNA precursor nu:leased OPN expression 3 X (P <. 01) 171 Western blot analyses In. vitro metastatic correlates Increased in Hep 313 lines after transfection with siOPN and/or miRNA 181a inhibitor <.01) Conclusion. MiRNA 181a decreases OPN expression in HCC cell lines. This previously undescnbed mechanism may confer metastatic characteristics to HCC (Surgery 2010;148.291-7)