While the activity of MMP9 is normally undetectable in healthy adult tissues, it is seen as highly active in a number of different inflammatory states. It can be found most active within the epithelial cells that make up the lining of the gastrointestinal tract, which is the origin of most colorectal cancers. To determine whether the MMP9 found in epithelial cells function defensively in the instance of colitis-associated cancer, researchers studied its role in both humans and mice.
The results showed that mice with higher activity of MMP9 in the epithelial cells had fewer tumors, as well as an increase in apoptosis—cell death that targets cells that are harmful or unneeded. In humans, the results showed a decrease in the speed of cell formation that contributes to cancer growth, as well as less DNA damage. Researchers also found that the MMP9 found in epithelial cells was able to suppress tumors by activating a specific pathway which increased apoptosis, initiated the end of cell cycles, and kept DNA damage lower.
The results of this research show that the human body has a natural defensive response to colitis-associated cancer, and with further analysis, researchers hope to be able to harness the effects of MMP9 in order to aid in the treatment of colorectal cancers. As MMP9 has proven beneficial in reducing tumor growth, a better understanding of the enzyme could prove useful in creating an applicable method to be used in cancer treatment regimes.
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