Shelly Fan in Singularity Hub:
Bacteria may seem like a strange ally in the battle against cancer.
But in a new study, genetically engineered bacteria were part of a tag-team therapy to shrink tumors. In mice with blood, breast, or colon cancer, the bacteria acted as homing beacons for their partners—modified T cells—as the two sought out and destroyed tumor cells. CAR T—the name for therapies using these cancer-destroying T cells—is a transformative approach. First approved by the US Food and Drug Administration (FDA) for a type of deadly leukemia in 2017, there are now six treatments available for multiple types of blood cancers. Dubbed a “living drug” by pioneer researcher Dr. Carl June at University of Pennsylvania, CAR T is beginning to take on autoimmune diseases, heart injuries, and liver problems. It is also poised to wipe out senescent “zombie cells” linked to age-related diseases and fight off HIV and other viral infections.
Despite its promise, however, CAR T falters when pitted against solid tumors—which make up roughly 90 percent of all cancers. “Each type of tumor has its own little ways of evading the immune system,” said June previously in Penn Medicine News. “So there won’t be one silver-bullet CAR T therapy that targets all types of tumors.” Surprisingly, bacteria may cause June to reconsider—the new approach has potential as a universal treatment for all sorts of solid tumors. When given to mice, the engineered bugs dug deep into the cores of tumors and readily secreted a synthetic “tag” to draw in nearby CAR T soldiers. The molecular tag only sticks to the regions immediately surrounding a tumor and spares healthy cells from CAR T attacks. The engineered bacteria could also, in theory, infiltrate other types of solid tumors, including “sneaky” ones difficult to target with conventional therapies. Together, the new method called ProCAR—probiotic-guided CAR T cells—combines bacteria and T cells into a cancer-fighting powerhouse.
More here.