The emerging field of synthetic biology—designing new biological components and systems—is revolutionizing medicine. Through the genetic programming of living cells, researchers are creating engineered systems that intelligently sense and respond to diverse environments, leading to more specific and effective solutions in comparison to current molecular-based therapeutics.

At the same time, cancer immunotherapy—using the body’s immune defenses to fight cancer—has transformed cancer treatment over the past decade, but only a handful of solid tumors have responded, and systemic therapy often results in significant side effects. Designing therapies that can induce a potent, anti–tumor immune response within a solid tumor without triggering systemic toxicity has posed a significant challenge.

Researchers at Columbia Engineering and Columbia University Irving Medical Center (CUIMC) announced today that they are addressing this challenge by engineering a strain of non–pathogenic bacteria that can colonize solid tumors in mice and safely deliver potent immunotherapies, acting as a Trojan Horse that treats tumors from within. The therapy led not only to complete tumor regression in a mouse model of lymphoma, but also significant control of distant, uninjected tumor lesions. Their findings are published today in Nature Medicine.