Fig 1: Effects of shRNA-mediated MRP4 transporter knock-down on demethoxycurcumin-O-glucuronides excretion and cellular glucuronidation in HeLa1A1 cells.(A) MRP4 knock-down decreased the excreted demethoxycurcumin-O-glucuronides (G1); (B) MRP4 knock-down reduced the accumlated demethoxycurcumin-O-glucuronides (G2) in extracellular medium; (C) MRP4 knock-down inhibited the excretion rates of G1 and G2; (D) The intracellular G1 and G2 levels were evaluated when MRP4 transporter was knock-down; (E) MRP4 knock-down resulted in decrease of overall cellular glucuronidation (G1 and G2) of demethoxycurcumin; (F) Effects of gene silencing on the protein level of MRP4. The concentration of demethoxycurcumin was 4 μM. All experiments were performed in triplicate (n = 3). Data were expressed as mean ± SD (n = 3). *, # p < 0.05, **, ## p < 0.01 and ***, ### p < 0.001 compared with that of control group of G1 or G2, respectively.