A novel AP-1/miR-101 regulatory feedback loop and its implication in the migration and invasion of hepatoma cells.
Bottom Line: Furthermore, reintroduction of miR-101 efficiently suppressed the AP-1 activity and pri-miR-101-2 transcription.These data thus suggest a novel AP-1/miR-101 regulatory circuitry, that is, AP-1 promotes the transcription of miR-101, whereas the expression of miR-101 reduces the level of ERK2 and c-Fos and thereby attenuates the AP-1 signaling.Further investigation disclosed that the AP-1 activator TPA-induced MMP9 activity and the TPA-promoted migration and invasion of hepatoma cells were significantly attenuated by miR-101 but were enhanced by miR-101 inhibitor.
Affiliation: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China.Show MeSH
Related in: MedlinePlus
Mentions: To examine the binding of c-Jun and c-Fos to the enhancer of miR-101-2, ChIP assays were performed in TPA-treated HepG2 cells. A specific band of the expected size was amplified from either the individual or combination of c-Jun and c-Fos antibody-precipitated DNA, using primers that covered the AP-1 binding sites in the −17.4 to −16.4 k enhancer of miR-101-2 (Figure 3A). Whereas knockdown of either c-Fos or c-Jun (Supplementary Figure S5A) markedly reduced the antibody-precipitated DNAs (Figure 3B), suggesting the interaction between AP-1 and the miR-101 enhancer in vivo. The direct interaction between c-Jun/c-Fos and canonical (Site A)/non-canonical (Site B) AP-1 binding sites was further verified by EMSA and antibody-supershift assays (Figure 3C and D).
Affiliation: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China.