EGCG and Green Tea Protect Anti-Tumor Immunity
Epigallocatechin gallate (EGCG) is the most abundant catechin in green tea, and one of the most studied polyphenols across the world1. The focus on this piece will be about the potential role of EGCG in aiding a TH1-promoting immunotherapy (such as from Immunocine) against something as aggressive as cancer.
To begin with a note of caution, publications and regulatory agencies have reported that the daily consumption of 800mg or more of EGCG can lead to liver toxicity issues2, 3. A cancer diagnosis does not mean these suggestions should be ignored as excess damage to one’s liver can bring a new set of issues to the environment especially when already dealing with cancer.
With that said, studies comparing the ability of different polyphenols to inhibit cancer growth have demonstrated that EGCG is supremely capable of accomplishing such a feat, primarily by causing cell cycle arrest4.
Other studies have shown that within 72 hours of direct contact, EGCG can therapeutically interact with a variety of cell signaling pathways critical to cancer cell survival and proliferation, with shorter timepoints for more bioavailable forms of EGCG5, 6, 7. This compound also can restore chemosensitivity to a variety of previously failed treatments8, 9, 10, and this has shown some staying power in clinical trials11, 12, though not in others13, 14.
While results regarding the role EGCG may play in cancer are encouraging, there is admittedly a ways to go before any regulatory stamp of approval is going to materialize.
Potentially more exciting though, regarding Immunocine technology, is how EGCG may coordinate with an active anti-cancer immune response.
One of the hallmark “breaks” or “checkpoints” cancers use to reduce immunity is through the PD-1 / PD-L1 axis15, something that has been shown to be positively affected by EGCG16, 17. This polyphenol has also been shown to inhibit other immunosuppressive tools tumors use, such as indoleamine 2,3-dioxygenase (IDO)18, 19 and Transforming growth factor (TGF)-β120, 21.
Concurrently, it would seem EGCG can enhance the killing power of cytotoxic T cells, the type of killer cells needed in a powerful Th1 immune response16, 22, 23, 24.
Some of this may seem counterintuitive, as EGCG is more well knowns for its anti-inflammatory roles25, 26, 27, and in fact has been shown to reduce the immune precursors needed to make Dendritic Cells28, 29. But this is when context becomes key. “Inflammation” is commonly viewed as bad, largely because we are constantly dealing with excessive and/or aberrant and/or unspecific inflammation that is causing problems. However, within the confines of a targeted immune response, inflammation is not only appropriate but necessary.
Therefore, putting the scientific pieces together, it would make sense to avoid excessive EGCG before the Immunocine treatment is able to begin, but that addition to one’s diet makes sense after the immune response is established. The relative safety profile of green tea / EGCG along with its potential therapeutic roles that could synergize with the immune response generated with Immunocine technology make this a worthwhile add after returning home.
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