From the mouth to the intestine to understand how to stop colon cancer in time. New research in the oncology field confirms the importance of the health of the intestinal microbiome and opens important perspectives on how to improve diagnoses and promptly treat this serious pathology. A research team at the Fred Hutchinson Cancer Center in Seattle studied a […]
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From the mouth to the intestine to understand how to stop a colon cancer. New research in the oncology field confirms the importance of health intestinal microbiome and opens up important perspectives on how to improve diagnoses and promptly treat this serious pathology. A research group of Fred Hutchinson Cancer Center of Seattle studied a bacterium present in the oral cavity of humans which is linked to the growth and progression of colon cancer. The study, published in the scientific journal Naturehighlighted that a specific subtype of bacterium, called “clade”, present within a subspecies of Fusobacterium nucleatummay underlie the onset of the disease and help fine-tune better non-invasive diagnostic methods for colon cancer and therapies targeting these bacteria to eliminate the tumor.
Research – The F. nucleatum, associated with dental plaque and to gingivitis, is naturally present in the microbiome of the mouth. To better understand how this bacterium influences the intestinal environment to such an extent that it favors the development of colon cancer, the first step was to analyze the F. nucleatum genomes found in colon tumors to compare them with those found in the mouth. The researchers sampled colon tumors from about 100 people, then fragmented the tumor tissues and placed them on agar plates to allow the bacteria present to grow. After isolating F. nucleatum from these cultures, the scientists performed a process called long-read sequencing to gain a complete view of the bacterium’s genome. The team compared the sequences of fabrics of colon cancer with those of F. nucleatum from the mouths of healthy individuals.
This revealed two main clades (groups) that are distinguished by some characteristics of the DNA and in the models of proteins coded. The bacteria from the two clades also looked different from each other under the microscope: specimens from the second clade were longer and thinner than those from the first. F. nucleatum animalis of colon tumors predominantly fell into the second clade. The characteristics of the latter are interesting: they seem to help bacteria survive the dangerous journey from the mouth to the intestine, such as the ability to eat in hostile environments such as the gastrointestinal tract strongly acid or to better invade cells. These bacteria also have “one of the most powerful acid resistance systems” found in bacteria, which allows them to tolerate the acidic environment of the stomach, he explains Christopher Johnston, a geneticist at the Fred Hutchinson Cancer Center and co-author of the study. In summary, the picture that emerged at the end of this study phase is that microbes from the second clade are more strongly associated with colon cancer. But it didn’t end here. More was needed to better understand how these microbes interact with the gut. To do this, this time a sample of guinea pigs animals.
The study on animal guinea pigs – The researchers administered to a group of mice a single oral dose of F. nucleatum animalis from clade 1 and to another a dose of clade 2 (the one associated with colon cancer), then they counted the number of tumors formed. Mice in the clade 2 group developed significantly more large intestinal tumors than those given the clade 1 bacterium or a control group in which neither bacteria was present. Metabolic molecules within tumors of mice with clade 2 bacteria were most strongly associated with a cellular damage due to oxidative stress, cancer cell division, and inflammation compared to mice in the control group and clade 1 bacterial group. What does all this mean? The hypothesis is that clade 2 bacteria contribute to producing a pro-inflammatory environment and pro-oncogenic. However, the research team also stressed that further evidence from a larger group of people with colon cancer is needed, as well as further research to understand exactly how bacteria may contribute to inflammation and cancer progression.
The expert’s opinion – “We have known for some time about the relationship between oral bacteria and the onset of colon cancer. The novelty of the research is given by the presence of a sub-strain of F. nucleatum animalis, clade 2, which overcomes gastric juice – which normally destroys harmful bacteria – and manages to feed and colonize the colon, often finding itself inside colon cancer cells ”, he explains to Fattoquotidiano.it the professor Gabriele Capurso, head of the Clinical Research Functional Unit at the Biliopancreatic Endoscopy and Echoendoscopy Operational Unit of the IRCCS San Raffaele Hospital and Deputy Director of the Center for Research and Treatment on Pancreatic Diseases of the San Raffaele. What perspectives can be opened from a therapeutic point of view? “In a more futuristic vision, these bacteria could be engineered and transformed into vectors which paradoxically carry an active ingredient curative. Staying on a more immediate level, we could work on specifics antibiotics or probiotics in order to rebalance the intestinal microbiome to reduce the risk of developing cancer. But even more effective is working with a prevention perspective.” The researchers say this discovery would be useful for early, non-invasive diagnoses. “First of all, from a prevention perspective, knowing that such a particular substrain of this bacterium is related to colon cancer could be useful for early diagnosis on stool samples or for prevention in subjects at risk, perhaps with a very strong family history, at a stage in which they are still well. This approach could also be effective for cancer pancreasan area in which we are about to publish our study in which a similar correlation emerges with the bacterium present in the case of periodontitis”. The importance of keeping the intestinal microbiome balanced appears increasingly crucial: “We must think of the microbiome as a multi-ethnic community. The more diversity, the greater enrichment for the organism and, in our specific case, more Health. Clade 2 is a strong bacterium, a sort of colonizer that wants to dominate, which reduces diversity and opens the door to the risk of serious diseases.” Is our lifestyle paving the way for this overbearing colonizer? “In fact, there is an association between consumption of ultra-processed foods, meat raised with antibiotics, smoking” but “gli” also have something to do with it antibiotics administered to children improperly and which select very resistant bacteria” as well as “theabuse of anti-acid drugs which can be taken without a medical prescription (which sterilize the gastric environment)”. All this produces a common effect: “The reduction of the complexity of the intestinal microbiome. A growing phenomenon in recent decades which is leading to an increase in health problems which we must remedy as soon as possible.”
