Fig. 5

PNS downregulated the expression of P-gp by inhibiting SIRT1/FoxO1/MDR1 signalling pathways in SLCs/MP cells. SLCs/MP cells treated with RPMI-1640 are indicated as controls. The protein levels of SIRT1 and FoxO1 and the mRNA levels of SIRT1 and MDR1 in SLCs/MP cells incubated with RPMI-1640, PNS (100 μg/ml, 200 μg/ml) or si-SIRT1 for 72 h were assessed using Western blotting and qRT–PCR. (A) Western blot analysis was performed to detect the protein levels of SIRT1 and FoxO1. (B) Analysis of protein expression. (C) qRT–PCR was used to determine SIRT1 and MDR1 mRNA levels. Experiments were repeated three times and data are expressed as the means ± SD. *P < 0.05 vs. control.