Potent mechanism-based inhibitors for matrix metalloproteinases

Matrix metalloproteinases ( MMPs) are zinc-dependent endopeptidases that play important roles in physiological and pathological conditions. Both gelatinases (MMP-2 and - 9) and membrane-type 1 MMP (MMP-14) are important targets for inhibition, since their roles in various diseases, including cancer, have been well established. We describe herein a set of mechanism-based inhibitors that show high selectivity to gelatinases and MMP-14( inhibitor 3) and to only MMP-2 ( inhibitors 5 and 7). These molecules bind to the active sites of these enzymes, initiating a slow binding profile for the onset of inhibition, which leads to covalent enzyme modification. The full kinetic analysis for the inhibitors is reported. These are nanomolar inhibitors (K-i) for the formation of the noncovalent enzyme-inhibitor complexes. The onset of slow binding inhibition is rapid (k(on) of 10(2) to 10(4) M-1 s(-1)), and the reversal of the process is slow (k(off) of 10(-3) to 10(-4) s(-1)). However, with the onset of covalent chemistry with the best of these inhibitors ( e. g. inhibitor 3), very little recovery of activity (< 10%) was seen over 48 h of dialysis. We previously reported that broad spectrum MMP inhibitors like GM6001 enhance MT1-MMP-dependent activation of pro-MMP-2 in the presence of tissue inhibitor of metalloproteinases-2. Herein, we show that inhibitor 3, in contrast to GM6001, had no effect on pro-MMP-2 activation by MT1-MMP. Furthermore, inhibitor 3 reduced tumor cell migration and invasion in vitro. These results show that these new inhibitors are promising candidates for selective inhibition of MMPs in animal models of relevant human diseases.