Matrix metalloproteinases in cancer metastasis: molecular targets for prostate cancer prevention by green tea polyphenols and grape seed proanthocyanidins.

Matrix metalloproteinases (MMP) play a crucial role in the development and metastatic spread of cancer. One of the earliest events in the metastatic spread of cancer is the invasion through the basement membrane and proteolytic degradation of the extracellular matrix proteins, such as, collagens, laminin, elastin and fibronectin etc, and non-matrix proteins. MMPs are the important regulators of tumor growth, both at the primary site and in distant metastases. Given the clear implications of MMPs in many human cancers, MMPs remain important targets of cancer therapy. Metastatic spread of cancer continues to be the greatest barrier in prevention or cure of cancer. The recognition that MMPs facilitate tumor cell growth, invasion and metastasis of cancer has led to the development of MMP inhibitors as cancer therapeutic agents. Understanding the molecular mechanism of metastasis is also crucial for the design and effective use of novel therapeutic strategies to combat metastases. In this short review article, we discuss the evidences that MMPs are associated with cancer metastasis and that they make a functional contribution to the process. Further, since considerable interest among human population is increasing with regard to the use of dietary botanical supplements for the prevention of age-associated diseases like some forms of cancer, we also discuss the beneficial effects of dietary botanicals, such as green tea polyphenols and grape seed proanthocyanidins, in chemoprevention of cancer with particular emphasis on the involvement of MMPs in prostate cancer.