Scientists have succeeded in creating genetically modified bacteria that do not cause disease in humans, but love to get inside tumors, and thanks to this particular interest, they are considered particularly useful for fighting cancer. These bacteria can be used to infiltrate a tumor and then produce special molecules that stimulate the immune system and then attack the cancer.
This bacterium was tested in a mouse model in two ways. In one of these tests, it was placed directly on the tumor, while in the other it was given intravenously to the mouse. Both approaches have been successful in overcoming the tumors’ ability to turn off signals that alert the immune system of their presence.
Columbia University professor of microbiology and immunology senior author Dr. “My graduate student Thomas [Savage] suggested using this platform as potentially to deliver chemokines,” Nicholas Arpaia said in a statement.
Chemokines are signaling proteins of the immune system. Different chemokines can attract different immune cells or make immune cells respond in a certain way. The bacteria in the tests were modified to contain a mutated version of the human chemokine gene that attracts “lethal” T-cells. A second strain was prepared to attract dendritic cells.
Dr. As Arpaia explains, “although T-cell responses specific to tumor-derived antigens are primed, sometimes they cannot be recruited into the tumor environment, even though there are primed anti-tumor T cells.”
Bacteria help with this. They can bypass the tumor’s defenses to reveal dendritic cells and T cells. The first of these eats the tumor, then presents the antigens of the cancer cells, which can then be detected by T cells. This process enables T cells to better fight tumors. Also, in these tests, the bacteria only spread inside the tumor and did not spread to other cells in the animal model.
The ability of tumors to evade detection by the immune system is an important area of study in preventing and treating cancer. The team is now considering optimizing the approach and drawing up plans to move on to clinical trials in the future.
The study was published in Science Advances.
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