Cancer cell survival appears partly dependent on antioxidative enzymes, whose expression is regulated by the Keap1-Nrf2 pathway, to quench potentially toxic reactive oxygen species generated by their metastatic transformation. AEM1 is an inhibitor of Nrf2-induced gene transcription at the antioxidant response element in cells at 1 to 10 µM. It sensitizes lung carcinoma A549 cells to chemotherapeutic agents and inhibits the growth of A549 cells in vitro and in vivo in animals. The effectiveness of AEM1 against cancer cells is restricted to those harboring mutations that render Nrf2 constitutively active.