The effectiveness of cancer treatment may highly depend on the bacteria living in your gut. According to two studies, gut bacteria have a significant impact on how well a cancer treatment will work.
Conventional medications such s ipilimumab, which is prescribed to people who suffer from advanced melanoma, stimulate the immune system to fight against cancer.
Some patients who take this medication have suffered an inflammation in the gut. This inspired Mathias Chamaillard at the University of Lille, France, to research the connection between the gut bacteria and this particular drug.
Chamaillard and his colleagues conducted research on mice. The researchers gave ipilimumab to mice that lack bacteria in their gut. The results have shown that the cancer treatment was less effective in those mice in comparison to mice with normal gut bacteria. Moreover, the effectiveness of the treatment was decreased when the mice with normal gut bacteria were given antibiotics to destroy their gut bacteria.
According to results from fecal samples, ipilimumab decreased two types of bacteria in the gut, Bacteroidales and Burkholderiales. Restoring these bacteria in both sets of mice led to improved effectiveness of the drug.
What’s in your gut?
The research team analyzed fecal samples from 25 people who suffered from melanoma in order to determine the levels of Bacteroidales. Next, they transplanted the samples into mice which lack gut bacteria and gave them ipilimumab. The results have shown that the mice which were given Bacteroidales transplants responded better to the cancer treatment.
According to Chamaillard, these bacteria improve the effectiveness of the drug. Chamaillard`s next research will be based on finding whether the bacteria living in a person`s gut will determine the effectiveness of the treatment.
Another study conducted by Thomas Gajewski and his colleague at the University of Chicago was based on how quickly the tumors developed in two groups of mice with different types of gut bacteria. The results have shown that a specific type of bacteria called Bifidobacteria were associated with a stronger immune response and slower cancer development. When this type of gut microbes were transplanted to another group of mice it decreased the tumor development with almost the same effectiveness as an anti-cancer treatment trialed in humans.
However, the influence of gut bacteria on the immune response and anti-cancer treatment is still not clear enough. “As we identify which bacteria have a similar effect in humans, it should be possible to develop probiotic supplements that specifically improve efficacy of immunotherapies,” says Gajewski.
“This fascinating research adds a new dimension to our understanding of how the latest cancer immunotherapies work,” says Graham Taylor, an immunologist at the University of Birmingham, UK. “They have remarkable potential, but at the moment only some patients benefit from them. The idea of using bacteria to help convince the immune system that there is an invader present and that it needs to kick into gear may offer a simple way to increase their effectiveness. So far this work has only been done using mice and we now need to see how it works in people.”