Anti-cancer probiotics
Researchers from the University of Cincinnati have developed a probiotic that attacks the defense mechanisms of cancer cells and increases the effectiveness of antitumor therapy.
Solid tumors have an extracellular matrix consisting of collagen and hyaluronic acid. This environment forms a barrier around the cells and hinders the access of antibodies and immune cells to tumors. Nalinikant Kotagiri and his colleagues experimented with E. coli Nissle, which has been used as a probiotic for more than 100 years, and created a technology that allows expressing any protein or enzyme in this bacterium. They designed E.coli Nissle, capable of secreting many vesicles containing an enzyme that destroys the extracellular matrix of cancer.
The secret is that bacteria, as a rule, thrive in conditions of low oxygen content and immunodeficiency – two characteristics peculiar to solid tumors, so specially developed bacteria naturally accumulate in them. Having a unique feature of being localized in tumors, the modified E.coli Nissle with the help of vesicles with an enzyme destroys the tumor matrix and makes it accessible to immune cells.
The researchers evaluated the effectiveness of probiotic bacteria in animal models of breast cancer and colon cancer. The bacteria were injected intravenously about four or five days before the start of cancer immunotherapy. During this time, modified E. coli Nissle colonized the tumor and destroyed its defense mechanisms to prepare for treatment.
Immunotherapy conducted against the background of probiotic treatment increased the survival rate of mice by two times compared to mice subjected to isolated immunotherapy. Imaging has shown that bacterial enzymes effectively destroy the extracellular matrix of the tumor and allow therapy to infect cancer cells.
The study also showed that the bacteria did not attack healthy cells in other organs, such as the heart, lungs, liver and brain. This means that they are not capable of causing infection, but additional studies are needed to confirm safety in large animals and in humans, especially in a state of immunodeficiency.
If the modified bacteria continue to show safety and efficacy, they can be used for various purposes, including the treatment of intestinal, oral and skin diseases. There is also the potential to create bacteria expressing proteins and molecules for monotherapy, rather than as an enhancer for other treatments.
The researchers have applied for a patent for a new technology.
Article by S.C.Thomas et al. Engineered Bacteria Enhance Immunotherapy and Targeted Therapy through Stromal Remodeling of Tumors is published in the journal Advanced Healthcare Materials.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of the University of Cincinnati: Breaking down cancer's defenses.