CS-2628

The hydroxamate-based metalloprotease inhibitor TAPI-2 bounds to hmeprin with inhibition constants IC ₅₀ 20±10 μM for hmeprin β subunit and 1.5±0.27 nM for hmeprin α subunit. Generally, hmeprin α is inhibited more strongly than the β subunit. Without affecting ADAM17 expression, TAPI-2 dramatically decreases the protein levels of NICD and its downstream target HES-1 in both HCP-1 and HT29 cells. Moreover, treating cells with TAPI-2 significantly decreases the CSC phenotype by -50% in both CRC cell lines. The dose-dependent effects of TAPI-2 on the sphere formation and protein levels of NICD and HES-1 confirm that the concentration used (20 μM) is within the effective dose range of TAPI-2 (5-40 μM).