Skin Microbiome Protects Against Cancer
The common human skin bacterium Staphylococcus epidermidis produces a substance that protects against cancer and could lead to new preventative treatments.
We mostly think about the human microbiome in terms of gut bacteria. However, microbes are found everywhere in the body, especially on the skin, which is in constant contact with the surrounding environment.
Bacterial communities vary significantly by their location on the body, and the health benefits they provide are likely to be specific to the area they are found on.
While studying how certain healthy skin bacteria fight off harmful pathogens, researchers at the University of California, San Diego stumbled upon a strain of Staphylococcus epidermidis that makes an interesting-looking substance.
The chemical made by the bacteria looks a lot like a key component of DNA, called adenine (one of the four DNA “building blocks”).
The researchers found that the chemical, called 6-N-hydroxyaminopurine (6-HAP) inhibited the production of DNA. When tested in cell cultures, 6-HAP prevented several types of tumor cells from growing and multiplying. Furthermore, the team found that 6-HAP was not toxic when injected into mice.
Amazingly, when melanoma cells were introduced to mice, animals that had received 6-HAP intravenously ended up with tumors more than 60% smaller than the mice that did not get 6-HAP.
The team also found that applying 6-HAP to the skin of mice (like sunscreen) protected them against UV radiation.
Staphylococcus epidermidis is commonly found on human skin, but researchers say that only about 20% of the healthy population is likely to have a strain that produces 6-HAP. Therefore, 6-HAP could be developed into a type of sunscreen to protect the wider population from the damaging effects of ultraviolet light.
Nakatsuji, T et al. A commensal strain of Staphylococcus epidermidis protects against skin neoplasia. Science Advances, 4.2 (2018): eaao4502.