Chemical inhibition of JAK2 decreases PD-1 ligand transcription. (A) Western analysis of phosphoJAK2 in HL cell lines (L428 and SUPHD1) treated with the increasing doses (2.5-10μm) of the specific JAK2 inhibitor, SD-1029. (B) RT-qPCR analysis of PD-L1 transcript abundance in the cell lines treated with SD-1029. Data are means (± SD) of triplicate measurements from the representative experiment shown in panel A. (C) The PD-L1 promoter regulatory module. STAT-responsive (ISRE) element and additional degenerate STAT-binding sites are indicated. This region was cloned into a pGL-luciferase vector (pGL3-PD-L1p). (D) Analysis of pGL3-PD-L1p luciferase activity in L428 and SUPHD1 HL cells treated with SD-1029 or vehicle. Data are means (± SD) of triplicate measurements from a representative experiment. Experiments in panels B and D were performed 3 times.