OATP1B1 is an important drug transporter with a complex regulatory mechanism. In this study, we wanted to investigate how LncRNA HOTAIR regulates the expression of OATP1B1 through its action on miR-206/miR-613 in HepG2 cells. The expression level of LncRNA HOTAIR, miR-206/miR-613, and OATP1B1 mRNA was detected by RT-qPCR, and the OATP1B1 protein level was detected by Western blot. The competitive endogenous RNA mechanism was validated by bioinformatics analysis and a dual-luciferase reporter gene assay. Our results showed that over- or under-expression of LncRNA HOTAIR correspondingly significantly increased or decreased the protein level of OATP1B1 in HepG2 cells, while no significant change in OATP1B1 mRNA level was observed. In addition, the stimulatory or inhibitory effect of LncRNA HOTAIR on OATP1B1 protein expression was correspondingly reversed by miR-206/miR-613 mimic or miR-206/miR-613 inhibitor. Finally, the reporter gene assay revealed that LncRNA HOTAIR can sponge miR-206/miR-613, which breaks the binding site of miR-206/miR-613 and OATP1B1 mRNA 3'-UTR, eliminating the stimulatory effect of LncRNA HOTAIR on OATP1B1 protein. Thus, we conclude that LncRNA HOTAIR can affect the expression of OATP1B1 in HepG2 cells by sponging miR-206/miR-613, which, in turn, prevents the binding of miR-206/miR-613 and OATP1B1 mRNA 3'-UTR.
Keywords: LncRNA HOTAIR; OATP1B1;3′-UTR; miR-206/miR-613.