ML241 is a potent and selective inhibitors of p97 ATPase.ML241 inhibits degradation of a p97-dependent but not a p97-independent proteasome substrate in a dual-reporter cell line. ML241 may be a novel agent for the chemotherapy of cancer, and provide a rationale for developing pathway-specific p97 inhibitors.

ML241 is cytotoxic to HCT15 and SW403 cells, with GI50s of 53 and 33 μM after treatment for 24 h, and 13 and 12 μM after treatment for 72 h, respectively

HeLa cells stably expressing ODD-luciferase are seeded onto a 96-well white solid bottom plate (5000 cells/well) and cells are grown for 16 h. Cells are treated with DMEM containing MG132 (4 μM) for 1h and washed with 100 μL PBS twice. DMEM containing 2.5% FBS, cycloheximide (50 μg/mL) and ML241 are added into the well. Four 96-well plates are prepared and one of the plates is taken out from incubator at each time point (70, 90, 120, or 150 min). Luciferin (50 μL of 1 mg/mL in PBS) is added into each well containing 50 μL of medium and incubated at room temperature with shaking at 500 rpm for 5 min. Luminescence intensity is determined with 0.1 ms integration time on the Synergy HT Microplate Reader