The team, led by Hani El-Nezami and Gianni Panagiotou of the School of biological Sciences at the University of Hong Kong, formulated Prohep, which when tested on mice was found to significantly slow down the growth of hepatocellular carcinoma (HCC) and reduce the size and weight of tumours.
An aggressive tumour and second most deadly cancer type globally, hepatocellular carcinoma accounts for most liver cancers and carries a sobering prognosis. At around US$6,000 per month, the cost of its treatment using targeted therapy is high.
Probiotics, however, which are commonly found in dairy food products, cost a fraction of this amount, meaning that microbiome-based therapeutics could therefore offer a cheaper approach in HCC intervention.
The researchers found that they could reduce tumour weight and size by 40% after feeding mice with Prohep one week before a tumour was injected.
While the beneficial role of probiotics in lowering gastrointestinal inflammation and preventing colorectal cancer has been frequently demonstrated, their immunomodulatory effects and mechanism in suppressing the growth of extra-intestinal tumours had not been explored until the HKU team began their study.
They found that the Prohep probiotic mixture’s beneficial effect was closely related to the abundance of certain beneficial bacteria that produce anti-inflammatory metabolites, which subsequently regulated the pro-inflammatory immune cell population via the crosstalk between gut and tumour.
Modulated gut microbiota, when applied to the liver, then suppressed hepatocellular carcinoma growth in the mice.
The researchers believe that Prohep has the potential to offer solutions for future treatment, or the development of alternative or complementary therapeutic and prophylactic methods for hepatocellular carcinoma.
Dr El-Nezami said: “The successful demonstration of probiotic efficacy in retarding hepatocellular carcinoma tumour growth in a pre-clinical model will warrant further testing of our approach in a microbiome-based intervention trial in cancer patients.
“The combined data from these studies could be applied to product development of immunotherapeutic drugs containing the studied bacterial communities. This will offer an opportunity for local pharmaceutical industries to adventure into this area of research to develop novel drugs, based on microbial ecosystems, to reduce HCC risks.”
He said that research was now needed on how to consume the probiotic mixture to obtain the best results, and to develop more efficient bacterial cocktails.
“Over the last few years, there have been a lot of studies that associate different disease types, such as infection diseases, cancer and metabolic diseases, with disturbances in the gut microbiota. However, in most of these cases the statistical analysis will propose just a couple of bacteria as the main contributors on the disease progression.”
For complex diseases, he said, bacterial communities of 20, 30 or 50 different species would be necessary for inducing the biological processes that will positively influence the host.
“Therefore the research team’s follow-up studies on HCC progression and the interplay with the gut microbiota are in that direction, to develop more efficient bacterial cocktails. Moreover, there are many more parameters that need to be elucidated in relation to this study.”
Whether these bacterial cocktails will be used as the basis for a drug or in tandem depends on the stage, size and grade of the tumour, and should ultimately be tested on humans, he added.