Metalloproteinases, including matrix metalloproteinases and aggrecanases, are known to have a role in the breakdown of connective tissue. Matrix metalloproteinases (“MMPs”) constitute a superfamily of proteolytic enzymes that are genetically related and capable of degrading almost all the constituents of extracellular matrix and basement membrane that restrict cell movement. Aggrecanases are members of the ADAMTS (A disintegrin and metalloproteinase with thrombospondin motifs) family of proteins. Aggrecanase-1 and aggrecanase-2 have been designated ADAMTS-4 and ADAMTS-5, respectively (Tang B L, Int J Biochem Cell Biol 2001, 33, 33–44).
The ADAMTS family is involved in cleaving aggrecan, a cartilage component also known as the large aggregating chondroitin sulphate proteoglycan (Abbaszade I et al., J Biol Chem 1999, 274, 23443–23450), procollagen processing (Colige A et al., Proc Natl Acad Sci USA 1997, 94, 2374–2379), angiogenesis (Vazquez F et al., J Biol Chem 1999, 274, 23349–23357), inflammation (Kuno K et al., J Biol Chem 1997, 272, 556–562) and tumor invasion (Masui T., et al., J Biol Chem 1997, 272, 556–562). MMPs have been shown to cleave aggrecan as well.
The loss of aggrecan has been implicated in the degradation of articular cartilage in arthritic diseases, for example osteoarthritis is a debilitating disease which affects at least 30 million Americans. Degradation of articular cartilage and the resulting chronic pain can severely reduce quality of life. An early and important characteristic of the osteoarthritic process is loss of aggrecan from the extracellular matrix, resulting in deficiencies in the biomechanical characteristics of the cartilage. Likewise, MMPs and aggrecanases are known to play a role in many disorders in which extracellular protein degradation or destruction occurs, such as cancer, asthma, chronic obstructive pulmonary disease (“COPD”), atherosclerosis, age-related macular degeneration, myocardial infarction, corneal ulceration and other ocular surface diseases, hepatitis, aortic aneurysms, tendonitis, central nervous system diseases, abnormal wound healing, angiogenesis, restenosis, cirrhosis, multiple sclerosis, glomerulonephritis, graft versus host disease, diabetes, inflammatory bowel disease, shock, invertebral disc degeneration, stroke, osteopenia, and periodontal diseases.
Therefore, metalloproteinase inhibitors are needed, including inhibitors of MMPs and aggrecanases.