DBeQ, also known as JRF 12, is a selective, reversible, and ATP-competitive inhibitor of the ATPase p97 for treatment of cancer. DBeQ impairs both ubiquitin-dependent and autophagic protein clearance pathways. DBeQ was shown to inhibit the ATPase activity of Vps4 with an IC50 of about 11.5 μM. To a less degree, it also inhibits hyphal growth. DBeQ blocks multiple processes that have been shown by RNAi to depend on p97, including degradation of ubiquitin fusion degradation and endoplasmic reticulum-associated degradation pathway reporters, as well as autophagosome maturation. DBeQ also potently inhibits cancer cell growth and is more rapid than a proteasome inhibitor at mobilizing the executioner caspases-3 and -7.