Green tea compound aids tumor-suppressing, increases anti-cancer protein

An antioxidant found in green tea may increase levels of p53, a natural anti-cancer protein, known for its ability to repair DNA damage or destroy cancerous cells, according to a new study published in the journal Nature Communications.

The study looked at the direct interaction between p53 and the green tea compound, epigallocatechin gallate (EGCG). P53 has several well-known anti-cancer functions, including halting cell growth to allow for DNA repair, activating DNA repair, and initiating programmed cell death or apoptosis if DNA damage cannot be repaired. One end of the protein, known as the N-terminal domain, has a flexible shape, and therefore, can potentially serve several functions depending on its interaction with multiple molecules, the researchers said.

EGCG is a natural antioxidant, which means it helps to undo the near constant damage caused by using oxygen metabolism. Found in abundance in green tea, EGCG is also packaged as an herbal supplement.

The researchers found that the interaction between EGCG and p53 preserves the protein from degradation. Typically, after being produced within the body, p53 is quickly degraded when the N-terminal domain interacts with a protein called MDM2. This regular cycle of production and degradation holds p53 levels at a low constant.

"Both EGCG and MDM2 bind at the same place on p53, the N-terminal domain, so EGCG competes with MDM2," said Chunyu Wang, MD, PhD, corresponding author and a professor of biological sciences at Rensselaer Polytechnic Institute, in a statement. “When EGCG binds with p53, the protein is not being degraded through MDM2, so the level of p53 will increase with the direct interaction with EGCG, and that means there is more p53 for anti-cancer function. This is a very important interaction."

The researchers said the direct interaction between p53 and EGCG points to a new target for therapies and interventions.