CTRL and melanoma: The aim of our study was to verify the ability of marizomib—a natural inhibitor that inhibits all three proteasome activities (caspase-like (C-L, β1), trypsin-like (T-L, β2), and chymotrypsin-like (CT-L, β5))—to induce cellular senescence in two malignant melanoma lines: A375 and G361.