NSC-405020 is a membrane type-I matrix metalloproteinase (MT1-MMP) inhibitor that specifically targets the hemopexin (PEX) domain rather than the catalytic domain of MT1-MMP (IC₅₀ >100 μmol/L). It does not inhibit the catalytic activity of MT1-MMP or MMP-2. NSC-405020 directly interacts with and binds to PEX in a vicinity of Met-328, Arg-330, Asp-376, Met-22 and Ser-470 of the druggable pocket in the full-length MT1-MMP structure, which affects the conformation and flexibility of blades I to IV of the β-propeller resulting in the decrease of the PEX-dependent homodimerization of cellular MT1-MMP.