Profiling of microRNA expression in hepatocellular carcinoma cells with overexpression of G protein alpha 12 active mutant

Heterotrimeric guanine nucleotide-binding proteins (G proteins) transmit extracellular signals from cell surface G protein-coupled receptors to intracellular effector molecules. Attention has been paid to the Gα12 family members because they mediate cell invasion, migration, and tumorigenesis. In our findings, Gα12 levels were higher in human HCCs than non-tumorous liver tissues. Array analyses using Huh7 cells stably transfected with Gα12QL (an active mutant form) enabled us to extract the microRNAs dysregulated by Gα12 active mutant. Of them, miR-122 was most greatly decreased. In addition, we found decreases of miR-200b/a, miR-192/215 levels. Dysregulation of the microRNAs changed the levels of key proteins associated with HCC cell migration/invasion. Huh7 hepatoma cells were transfected with pCMV or the plasmid encoding for activated mutant of Gα12 (Gα12QL). Stable transfectants were selected by incubating the cells in culture medium containing Geneticin for 3 weeks. We performed a miRNA microarray for the identification of global microRNA expression changes using WT-Huh7 and Huh7-Gα12QL cells. RNA for each set was harvested from quadruple plates.