Engineering Bacteria to Treat Cancer

A deliberate injection with engineered bacteria may stimulate the immune system to attack tumors, new research finds.

The study tested a strain of Escherichia coli engineered to produce molecules unique to cancerous cells in solid tumors in mice. They found that this bacterial “vaccine” prompted an immune response that reduced tumors and prevented their regrowth.

“The net effect is that the bacterial vaccine is able to control or eliminate the growth of advanced primary or metastatic tumors and extend survival in mouse models,” Jongwon Im, a PhD student at Columbia Univ. who worked on the bacterial engineering project, said in a statement.

Immunotherapy, or the recruiting of the patient’s own immune system to fight cancer, has a long history, and there are now several types available to patients. For instance, chimeric antigen receptor (CAR) T-cell therapy takes a person’s own T-cells, a type of white blood cell, and exposes them to a viral vector with molecules specific to cancer in order to train the T-cells to attack cancerous cells. According to the MD Anderson Cancer Center, CAR T-cell therapy is approved to treat some types of leukemia, lymphoma, and myeloma.

However, not all immunotherapies work for all cancers, and not all patients respond well to immunotherapy. Part of the problem is that cancer is not one disease, but thousands, each driven by different mutations that cause cells to grow out of control. What triggers an immune response in one patient may do nothing for a patient whose cancer is caused by totally separate...