USP2 and melanoma: Indeed, similar to USP2 depletion, ML364 treatment induced VPRBP destabilization and heightened PD-L1 protein levels in a variety of human tumor lines, including those that do (human lung carcinoma H460 and human melanoma A375 cells; Fig. 6a) or do not (H1299 cells; Fig. 6b) express wild-type p53.