In the intestine of a specific species of Japanese frogs he hides a bacterium that it seems to have surprising anti-tumor capabilities. The discovery comes from a group of researchers from the Japan Advanced Institute of Science and Technology (JAIST) who in an experimental model on mice affected by colorectal cancer he tested 45 bacterial strains isolated from the intestines of amphibians and reptiles, identifying one that completely eliminated the tumor: theAmerican Ewingella (E. Americana).
This study – explain the authors – is part of one of the most innovative areas of oncology research, which explores the possible interactions between the gut microbiome and cancerbut with a direct approach never attempted before: intravenously administering bacterial strains isolated from the intestines of amphibians and reptiles to study the their effects on tumor cells.
Where does the bacterium come from?
Starting from three different animal species, the Japanese tree frogs, the Japanese newt (Cynops pyrrhogaster) and Japanese grass lizards (Takydromus tachydromoides), the researchers isolated 45 intestinal bacteria. They discovered that not only that nine of these they really had anti-tumor effectsbut that above all one, the bacterium Ewingella Americana (E. Americana), taken from the intestine of Japanese tree frogs, showed aTruly surprising therapeutic efficacy.
Colorectal cancer, scientists identify the “Big Bang moment”: it hides the tumor from the immune system
In fact, it was enough in mice suffering from colorectal cancer a single intravenous administration of E. Americana to completely eliminate the tumor, with a 100% complete response, without causing side effects. This means that there were no longer any detectable traces of the tumor after treatment, a result – explain the authors – which exceeds those associated so far with treatments available today, including chemotherapy and immunotherapy.
How the tumor attacks
There are several factors that researchers believe explain how the E. Americana bacterium managed on its own eliminate cancer in mice. It does this through two complementary mechanisms. Once it reaches the tumor, this bacterium it accumulates selectively only in the tumorattacking him. The researchers measured that within 24 hours of administration, bacterial counts within the tumors had increased 3,000-fold. Furthermore, the presence of the bacterium activates the immune system calling into play T lymphocytes, B lymphocytes and neutrophils, which by attacking the bacterium contribute to the destruction of tumor cells.
How is this possible
The results of this study are surprising because they show how the bacterium E. Americana can only attack the tumorwithout colonizing healthy organs, which instead would have had potentially very harmful side effects on the animals, or causing side effects. In fact, no chronic toxicity was recorded in the 60 days of monitoring following treatment.
There are several factors that contribute to this exceptional antitumor specificity of the bacterium. First of all, E. Americana is a facultative anaerobic bacterium, meaning it can live even in the presence of oxygen, but grows better in its absence.
For this reason proliferates in the tumorbecause tumor tissues present by their nature a hypoxic environmenti.e. with little oxygen present. Furthermore, the tumor produces a protein that defends it from the immune system and allows it to grow. But this “protection” from the immune system is also what makes it more vulnerable to the bacterium, allowing it to survive in the tumor.
While it has led to some truly significant results, it’s worth remembering that it’s still about an experimental study on animals. This means that we cannot talk about the discovery of a new anti-tumor therapy, but about an important first step in this direction. In fact, the study provided – explain the authors – “a proof of concept for a new therapy of cancer using natural bacteria”, but further studies will be needed to explore new possible anti-tumor therapies.
