Figure 4.

Tazemetostat reverses major histocompatibility complexes II-specific IFN-γ resistance MeWo, SKMEL-1, and CHL-1 cells were pretreated with tazemetostat (1 µM or 5 µM) for 3–4 days and stimulated with IFN-γ for 72 hours. (A–B) On harvest, cells were stained with the indicated antibodies and visualized for surface expression using flow cytometry. (C) Western blots using whole cell lysates and probed with antibodies specific for the indicated targets. HLA-DR expression was below the limit of detection for western blot in SKMEL1 (less sensitive than flow cytometry). (D–E) Quantitative real time PCR performed on messenger RNA isolates after tazemetostat treatment and IFN-γ stimulation. CIITA, class II major histocompatibility complex transactivator I; DMSO, dimethyl sulfoxide; EZH2, enhancer of zeste 2 polycomb repressive complex 2 subunit; HLA-DR, human leukocyte antigen-DR; IFN, interferon; MFI, mean flourescence intensity; PD-L1, programmed death ligand 1.