AsianScientist (Feb. 26, 2016) – Here is a study that adds to the growing body of research on how gut bacteria is so much more important than we might first realize. Researchers based in Hong Kong have demonstrated in animal models that manipulating the composition of gut microbiota may help to shrink cancerous tumors found outside of the gut. Their work was published in the Proceedings of the National Academy of Science.
The role that probiotics play in the treatment and prevention of gut-related disorders, such as colorectal cancer, have been well documented in the past. This study, however, is the first to show the beneficial effect of probiotics on hepatocellular carcinoma (HCC), the most common type of liver cancer and a common cause of cancer-related death.
Furthermore, in their paper, the authors from the University of Hong Kong (HKU) proposed a mechanism by which the altered bacterial community impacts the progression of HCC—opening up the possibility that we may be able to apply the same principles to treatment of other cancers.
To investigate the efficacy of probiotics in controlling HCC and suppressing tumor growth, the research team developed a probiotic cocktail, Prohep, for use in mouse models. Prohep’s individual components induce different biological processes that alter not only the communication between the bacteria but also between the bacteria and the host, Associate Professor Gianni Panagiotou from the Systems Biology & Bioinformatics Group at HKU, the corresponding author of the study, told Asian Scientist Magazine.
In the mice studied, this special probiotic mixture served to increase the amounts of certain gut bacteria, particularly Prevotella and Oscilibacter, which are both producers of anti-inflammatory metabolites. As a result, after 35 days, the researchers observed a 40 percent reduction of tumor weight and size compared to the control.
“In our study, the impact of the anti-inflammatory molecules produced by the beneficial bacteria was not directly on the inflammation site. These molecules reduced the frequency of a particular type of immune cells in the gut, Th17 cells, that promote inflammation,” said Panagiotou.
“Since inflammation is a key process in cancer progression, by reducing Th17 frequency in the gut, and subsequently their recruitment through blood circulation in the liver, we succeeded in interrupting the tumor growth.”
It is still too early to tell how these findings could contribute to a potential treatment for liver cancers. Naturally, there needs to be an investigation into how humans will respond to Prohep.
“Whether our bacterial cocktail is going to be used as a basis for a drug or in tandem [with other drugs] also depends on the stage, size and grade of the tumor,” explained Panagiotou.
Nevertheless, this research offers valuable insight into the molecular mechanisms underlying the beneficial effect of probiotics beyond the gut.
Moving forward, the research team plans to conduct follow-up studies on HCC progression and the interplay with gut microbiota to develop more effective bacterial cocktails.
The article can be found at: Li et al. (2016) Probiotics Modulated Gut Microbiota Suppresses hepatocellular Carcinoma Growth in Mice.
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