Scientists engineer cancer-fighting bacteria

Bacteria holds promise for future tumor treatment


(Taiwan News) -- Columbia University scientists have successfully used genetically reprogrammed bacteria to alert the immune system to the presence of cancer cells, according to a study published in Nature Medicine on July 3.

The treatment has only been shown to be effective in mice thus far, but researchers are confident similar techniques will be used to treat humans in the future, reports The New York Times (NYT). Dr. Michael Dougan, an immunologist at Massachusetts General Hospital, believes that “at some point in the future, we will use programmable bacteria for treatment.”

According to the NYT report, human immune systems are not always capable of recognizing malignant cells as dangerous due to their production of a protein called CD47. Our immune systems ignore cells with this CD47 "don't touch me" signal, allowing them to grow into harmful tumors.

Previous research has focused on creating antibodies that attach to a cancer cell’s CD47 proteins, giving the immune system a chance to attack them as if the protein were not there. However, this method comes with negative side-effects and has not proven effective in treating large tumors.

Columbia University researchers Nicholas Arpaia and Tal Danino, however, have tested a new method of alerting the immune system to a tumor via helpful microorganisms.

Bacteria frequently colonize tumors in an attempt to avoid the immune system. The researchers used this knowledge to engineer bacteria that fight tumors from within.

Once inside the tumor, the bacteria release nanobodies that mask the CD47 proteins produced by malignant cells and allow the immune system to detect the tumor.

The bacteria work as a Trojan horse, targeting tumors while causing minimal side effects. Not only did the bacteria manage to engage a stronger immune response, but smaller tumors in the mouse subjects also started to shrink after the treatment.

The NYT report emphasizes that while researchers aim to turn this into a commercial treatment, there is no guarantee it will be successful in humans.