Figure 4.

LPS or CM generated by NSCLC cells modulated the level of PD-1/PD-L1 expression in activated THP-1 human monocytes. (A) LPS treatment increased the mRNA levels of PD-1 and PD-L1 in activated THP-1 cells as determined by qRT–PCR. (B–C) LPS increased the protein level of PD-L1 in activated THP-1 cells as determined by flow cytometry (B) and Western immunoblotting (C). (D–F) Incubation of activated THP-1 cells in CM generated by NSCLC cells enhanced the level of PD-L1 (D, E) and COX-2 (F). (G) Silencing of COX-2 with four specific COX-2 siRNA (50 nM) failed to consistently modulate NSCLC CM-induced PD-L1 expression in activated THP-1 cells.