Probiotics suppress liver cancer growth in mice
Researchers from The University of Hong Kong have developed a probiotic mixture that has been shown to suppress cancer growth in extraintestinal regions such as the liver. [Proc Natl Acad Sci U S A 2016;113:E1306-E1315]
Their recent study in mice is the world’s first study in liver cancer that has applied probiotics and generated positive results.
The researchers administered their novel probiotic mixture, Prohep, to mice orally 1 week before or on the same day of tumour inoculation. After 38 days of tumour inoculation, the average liver tumour volume in mice fed with Prohep was 40 percent lower than that in control mice.
Notably, the 40 percent tumour volume reduction was achieved earlier in mice fed with Prohep 1 week before tumour inoculation (achieved on day 31) than those fed on the day of inoculation (achieved on day 35).
“Future research will be to find out how to consume the probiotic mixture to obtain the best results, and to develop more efficient bacterial cocktails,” noted lead investigator Dr. Hani El-Nezami of the School of Biological Sciences, The University of Hong Kong.
The effect of probiotics on liver cancer may be attributed to the decrease in T helper 17 (Th17) cells and interleukin-17 (IL-17) as shown in the study.
“Th17 was likely to be the major producer of IL-17, an interleukin linked to liver cancer growth and angiogenesis that is present in the tumour microenvironment. In our study, the use of probiotics shifted the gut microbial community towards certain beneficial bacteria, including Prevotella and Oscillibacter, which are known to produce anti-inflammatory metabolites,” the researchers explained. “These metabolites subsequently promoted the differentiation of anti-inflammatory T-cells in the gut. This in turn reduced the levels of Th17 and hence IL-17 in the tumour microenvironment, weakening liver tumour angiogenesis and suppressing its growth.”