Investigation of RA-V-induced dual reduction of HIF-1α and PD-L1 expression in colon cancer cells. (A) Effects of RA-V-treatment on CT26 cells with different concentrations. Western blotting analysis for the expression of HIF-1α, PD-L1, HMGA1, p-Erk and p-Akt. (B) Quantitative analysis of the expression of HIF-1α and PD-L1 in Fig. 4A by optical densitometry using Image J. Data are given as mean ± SD (n = 3). (C) Immunofluorescence assay of PD-L1 expression in CT26 cells after different concentrations. The nucleus was stained with Hoechst 33342 (blue). The PD-L1 protein was labeled with FITC (Green). Scale bar = 10 μm. (D) Effects of RA-V-treatment on HCT116 cells with different concentrations. Western blotting analysis for the expression of HIF-1α, PD-L1, HMGA1, p-Erk and p-Akt. (E) Effects of RA-V-treatment on SW620 cells with different concentrations. Western blotting analysis for the expression of HIF-1α, PD-L1, HMGA1, p-Erk and p-Akt. All the samples from total cell lysates for Western blotting analysis ran at equal protein (20 μg). ∗P < 0.05, ∗∗∗P < 0.001.