Containing the active ingredient of MLN4924 which acts as a substrate-assisted inhibitor of the NEDD8-activating enzyme (NAE). NAE activates NEDD8 (Neural precursor cell expressed, developmentally down-regulated 8) for conjugation to a variety of ubiquitin E3 ligases. NAE inhibitor binds to and inhibits NAE, which may result in the inhibition of tumor cell proliferation and survival. This cell permeable compound selectively inhibits NAE activity and results in inhibition of the NEDD8 pathway. Treatment of cells with MLN4924 results in inhibition of the NEDD8 pathway, making MLN4924 a new approach to targeting the UPS for the treatment of cancer.