Keap1-Nrf2-IN-4 is a potent neddylation inhibitor. Keap1-Nrf2-IN-4 exhibits potent anti-proliferation activity against MGC-803 cells ( IC 50 =2.55 µM). Keap1-Nrf2-IN-4 blocks the migration ability and induces apoptosis of gastric cancer cells. Keap1-Nrf2-IN-4 inhibits tumor growth without obvious toxicity.