Is green tea your tea of choice? Or are you more of an Earl Grey person? Regardless of personal preferences, a new study is supplying some serious motivation for all of us to sip on some more green tea from time to time.
Researchers from the Rensselaer Polytechnic Institute report that a naturally occurring antioxidant found in green tea may help protect and increase levels of a cancer-fighting protein in the human body. This anticancer protein is technically called p53 but also carries the affectionate nickname “guardian of the genome” thanks to its efficiency at repairing damaged DNA and killing cancer cells.
In short, green tea appears to put one’s body in a better position to ward off and fight cancer. The green tea antioxidant called epigallocatechin gallate (EGCG) binds to, protects, and fosters increased production of cancer-fighting p53 proteins.
“Both p53 and EGCG molecules are extremely interesting. Mutations in p53 are found in over 50% of human cancer, while EGCG is the major antioxidant in green tea, a popular beverage worldwide,” says corresponding study author Chunyu Wang, a professor of biological sciences at Rensselaer Polytechnic Institute. “Now we find that there is a previously unknown, direct interaction between the two, which points to a new path for developing anticancer drugs. Our work helps to explain how EGCG is able to boost p53’s anti-cancer activity, opening the door to developing drugs with EGCG-like compounds.”
Professor Wang even went on to call p53 “arguably the most important protein in human cancer.”
Essentially, when p53 proteins are damaged or in low supply, cancer cells find it much easier to grow and spread. P53 fights cancer in a few different ways; it is known to repair damaged DNA, stop cell growth to facilitate DNA repair, and it is also responsible for starting the process known as apoptosis (programmed cell death) when DNA damage is too extensive to be salvaged.
One end of the p53 protein features a “flexible shape.” This end, referred to as the N-terminal domain, is considered responsible for much of p53’s ability to serve multiple purposes depending on the molecules that come into contact with the N-terminal domain.
That’s all well and good, but where does green tea and its antioxidant EGCG come into play? Study authors discovered that when EGCG makes contact with a p53 protein, a unique interaction occurs that protects p53 from breaking down. Normally, in the absence of EGCG, p53 proteins in the human body are quickly degraded whenever their N-terminal domain makes contact with another protein called MDM2. This is why p53 levels in most people remain low pretty much all the time.
EGCG stops this from happening by binding to p53 at the N-terminal domain before MDM2 has a chance to do so itself. When this occurs, p53 proteins live longer in the body, which eventually leads to higher overall p53 levels.
“Both EGCG and MDM2 bind at the same place on p53, the N-terminal domain, so EGCG competes with MDM2,” Professor Wang explains. “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.”
Besides just giving us all a great reason to drink more green tea, this research also opens the door for newly developing cancer drugs and treatments.
“By developing an understanding of the molecular-level mechanisms that control key biochemical interactions linked to devastating illnesses such as cancer and Alzheimer’s disease, Chunyu’s research is laying the groundwork for new and successful therapies,” concludes Curt Breneman, dean of the Rensselaer School of Science.
The full study can be found here, published in Nature Communications.