In a normal, healthy body, MMPs play an important role in such processes as fetal development, ovulation, wound healing, and cell growth and regeneration. However, when too many MMPs are produced or are present at the wrong time, they can break down the material, known as extracellular matrix, that holds cells together inside tissues. This activity occurs in diseases in which healthy tissue is broken down or unhealthy tissue grows, as in cancer and rheumatoid arthritis, Jablons said. Cancer tumors grow and spread, interfering with the functions of healthy tissue. Cancer researchers believe that a MMPI, called AG3340, will block these processes while limiting the damage that may result from a broad suppression of MMPs.
Invasion is the expansion of tumors into neighboring healthy tissue.
MMPs act to break down the matrix structure of the healthy tissue, paving the way for the invading malignant tumor. Metastasis is the spread of tumor cells to distant locations in the body. MMPs loosen the tissue structures, permitting cancer cells to break off and spread to other locations where they can grow. In addition, the breakdown of tissues themselves trigger the release of more MMPs, which promotes further tumor growth and expansion. Angiogenesis is the development of new blood vessels.