Fig. 5

US exposure repressed P-gp expression by activating ZEB1-miR-200c/34a negative feedback loop. a US exposure decreased ZEB1 expression in MCF-7/ADR cells, while NAC pretreatment inhibited ZEB1 down-regulation in response to US exposure; N = 3; data are represented as mean ± s.d; *P < 0.05 compared with CON group; (b) ZEB1 directly binds to miR-200c/34a promoter in HEPG2 cells. Results were obtained from CHIP-seq of ZEB1 in ENCODE database; (c) The ZEB1-binding sites in miR-200c/34a promoter in MCF-7/ADR cells were detected by PCR gel; (d) Knockdown of ZEB1 increased miR-200c/34a expression in MCF-7/ADR cells; N = 3; data are represented as mean ± s.d; *P < 0.05; (e) Predicted miR-34a-3p seed sequence match to the sequence in the 3’ UTR of ZEB1 mRNA. Mutations were generated in the complementary sequences that match to the seed region of miR-34-3p; (f-g) Luciferase reporter assay was used to determine miR-34a-3p (f) and miR-200c (g) direct targeting the ZEB1 3’ UTR; (h-i) MiR-34a/200c overexpression reduced the ZEB1 expression in MCF-7/ADR cells; N = 3; data are represented as mean ± s.d; *P < 0.05; (j) Knockdown of ZEB1 decreased P-gp expression, which could be reserved by miR-34a/200c inhibition; N = 3; data are represented as mean ± s.d; *P < 0.05 compared with si-ZEB1 alone