WS-383 (0.03-3 μM;24 hours) blocks Cul3 neddylation at 3 μM and also has certain inhibition of Cul1 neddylation at 10 μM but was not effective in inhibiting neddylation of other cullin members. WS-383 (0.03-3 μM;24 hours) increases Cul1, Skp1 (adaptor protein), F-box protein, and RBX1/RBX2 RING protein form SCF E3 complex. Cyclin dependent kinase inhibitor 1A (p21) and cyclin dependent kinase inhibitor 1B (p27) expression in a dose-dependent manner in MGC-803 and KYSE70 manner.