Scientists from the University of Waterloo (Canada) have succeeded in modifying a bacteria, the Clostridium sporogenesso that it “eats” the nutrients at the heart of cancerous tumors. By targeting areas deprived of oxygen and rich in cellular debris, these microorganisms attack the disease where conventional treatments have difficulty working.
Professor of chemical engineering Marc Aucoin explains that the bacterial spores which penetrate the tumor mass find “lots of nutrients and no oxygen”, then multiply. “We colonize this central space, and the bacteria eliminates the tumor from the body.» The stated objective is to offer an alternative or complement to conventional treatments such as chemotherapy or radiotherapy, often associated with high toxicity and serious side effects for patients.
Interest in these “anti-cancer bacteria” is not new. Several works published in recent years have shown that strains ofE.coli or Salmonella genetically modified could reduce the size of tumors in mice. Solid tumors, which represent the majority of adult cancers, are difficult to treat due to their heterogeneous microenvironment and drug resistance.
A biological “electric circuit”
The Canadian team had to overcome a major obstacle: if Clostridium sporogenes survives in a world without oxygen, the bacteria dies when it reaches areas close to the tumor, where oxygen is present. The researchers therefore modified it to introduce oxygen tolerance.
In a more recent publication relayed by Futurism, the scientists explain that they have also implemented a cellular communication system for bacteria which allows them to activate certain genes only when the bacterial population reaches a certain density in order to avoid “off-target” attacks.
Applied mathematics professor Brian Ingalls compares the device to a biological electrical circuit: “Using synthetic biology, we built something that looks like an electrical circuit, but instead of wires, we used fragments of DNA.» Each DNA fragment fulfills a specific function and the whole forms a programmable system capable of acting in a predictable manner. The researchers even integrated a green fluorescent protein to be able to signal the activation of the program.
Despite these notable advances, caution remains in order since these are currently only preclinical studies. Human trials are only just beginning in the broader field of therapeutic bacteria, so no miracle cure has yet been announced.
If the results are confirmed, this approach could open the way to more targeted treatments, capable of exploiting the biology of tumors themselves.
