A Bacterial Living Therapeutics with Engineered Protein Secretion Circuits To Eliminate Breast Cancer Cells

Abstract Cancer therapy can be limited by potential side effects, and bacteria-based living cancer therapeutics have gained scientific interest in recent years. However, the full potential of bacteria as therapeutics has yet to be explored due to engineering challenges. n this study, we present a bacterial device designed to specifically target and eliminate breast cancer cells. We have engineered Escherichia coli (E. coli) to secrete a Shiga toxin, HlyE, which is a pore-forming protein that binds to HER2 receptors on breast cancer cells. This binding is facilitated by a nanobody expressed on the bacteria’s surface via the Ag43 autotransporter protein system. Our findings demonstrate that the nanobody efficiently binds to HER2+ cells in vitro, and we have utilized the YebF secretion system to secrete HlyE and kill the target cancer cells. Overall, our results highlight the potential of our engineered bacteria as an innovative strategy for breast cancer treatment.