Fig. 5

Effect of Cur on the expression levels of SP-1, SREBP-2, and NPC1L1 proteins and the activation of PPARγ resulted in the suppression of the SP-1 and SREBP-2 proteins in Caco-2 cells. A Based on TCGA database, NPC1L1 expression was higher in CRC tissues. B, C, and D Caco-2 cells were incubated with different concentrations of Cur for 48 h, and the expression levels of the SP-1 (B), SREBP-2 (C), and NPC1L1 (D) proteins were determined by Western blot analysis. (n = 3, 4, and 7). E and F Caco-2 cells were incubated with various concentrations (0, 5, 10, and 15 µM) of PPARγ agonist BRL for 48 h, and the expression of SP-1 (E) and SREBP-2 (F) proteins were detected by Western blot analysis. (n = 3 and 6). G and H Cells of the Caco-2 line were incubated with the indicated concentrations of Cur (20 µM) and PPARγ antagonist GW (5 µM) for 48 h, and the expression levels of SP-1 and SREBP-2 proteins were determined by Western blot analysis. (n = 4). Data presented as mean ± SEM. ^*P < 0.05 vs control, ^**P < 0.01 vs control, ^***P < 0.001 vs control, ^#P < 0.05 vs Cur, ^##P < 0.01 vs Cur. Cur, curcumin; SP-1, specificity protein-1; GAPDH, Glyceraldehyde-3-phosphate dehydrogenase; SREBP-2, sterol regulatory element-binding protein-2; NPC1L1, Niemann-Pick C1-like 1; BRL, rosiglitazone, BRL 49653; GW, GW 9662; PPARγ, peroxisome proliferator-activated receptor gamma; TCGA, the Cancer Genome Atlas; CRC, colorectal cancer; SEM, standard error of the mean