The zinc-dependent and calcium-containing family of endopeptidascs called matrix metalloproteinases (MMPs) play a crucial role in the degradation of extracellular matrix (ECM) and tissue remodeling.Of all the identified MMP family members,MMP-2 has been considered as a promising target for cancer therapy because of its tight correlation with tumor progression.In our laboratory,intensive efforts have been devoted in recent years to identify pyrrolidine derivatives as effective MMP inhibitors.Most compounds,such as LY52 (See Fig.1),showed high inhibition against MMP-2.