The human body contains trillions of cells that normally maintain their location in order to function correctly. Cancer cells, however, can move throughout the body by a process known as metastasis where they invade normal tissue producing lethal consequences. In order to metastasize, cancer cells first detach from their original location and move through passages produced from the extracellular matrix degrading protease known as the matrix metalloproteinase-9 (MMP-9) which is heavily over expressed in cancer cells. These passageways lead cancer cells into blood vessels (Fig. 1 depicts the initial phase of metastasis) where they circulate to remote sites and establish secondary tumors (Fig. 2 illustrates secondary tumor formation).
Since metastasis is the most deadly aspect of cancer, inhibiting it is an extremely important aspect of fighting cancer. Interestingly many epidemiological studies have reported that the consumption of green tea can significantly decrease cancer risk. Furthermore, the compound Epigallocatechin-3-gallate (EGCG), a major component of green tea (Fig. 3 is the chemical structure of EGCG), has anti-metastatic properties that partly come from MMP-9 inhibition. As demonstrated in figure 4, EGCG adequately docks into the active site pocket of MMP-9 perhaps representing the molecular interaction that inhibits MMP-9. (Fig. 4 shows the EGCG molecule in orange super positioned onto an MMP-9 inhibitor molecule in magenta emphasizing their similar ring structures and highlighting a putative EGCG binding pocket on the MMP-9 molecular surface colored in grey). This molecular information could facilitate the design of better MMP-9 inhibitors that effectively impede metastatic cancer and hopefully peak interest in green tea as a powerful nutritional weapon in the fight against cancer.
