CCL21 promotes chemoresistance in HCT116 cells. (a) HCT116 cells were treated with or without CCL21 (100 ng/mL) for 72 h and then were exposed to doxorubicin (DOX) for 48 h and measured the cell viability by MTT. (b) HCT116 cells were treated with or without CCL21 (100 ng/mL) for 72 h and were then exposed to 5-FU for 48 h and measured the cell viability by MTT. (c) HCT116 cells were treated with or without CCL21 (100 ng/mL) for 24 h. The mRNA levels of several chemoresistance genes were analyzed by qRT-PCR. ∗
P < 0.05. (d) HCT116 cells were treated with or without CCL21 (100 ng/mL) for 24 h, 48 h, and 72 h, and the protein level of P-gp was analyzed by western blotting. HCT116 cells were treated with CCL21 (10, 50, 80, 100, and 150 ng/mL) for 72 h, and the protein level of P-gp was analyzed by western blotting. (e) HCT116 cells were treated with CCL21 (100 ng/mL) for 72 h, and then Rh123 (5 μM) was added to the cells and incubated for 2 h. The cells were washed five times with cold PBS and fluorescent intensity images were obtained via fluorescent inverted microscope. (f) HCT116 cells were treated with CCL21 (100 ng/mL) for 72 h, and then Rh123 (5 μM) was added to the cells and incubated for 2 h. The cells were washed five times with cold PBS and digested and we used the flow cytometry to detect fluorescent intensity.