American scientists have engineered bacteria to act as “Trojan horses,” smuggling cancer-killing viruses directly into tumors while evading immune system detection.
Story Highlights
- Columbia Engineering develops CAPPSID system using engineered Salmonella bacteria to deliver oncolytic viruses into tumors
- Bacteria act as “invisibility cloak” protecting viruses from immune system antibodies until reaching cancer cells
- First-ever engineered cooperative system between bacteria and viruses offers hope for immunocompromised patients
- Technology builds on 19th-century bacterial cancer treatments while addressing modern immune system limitations
Revolutionary Dual-Organism Cancer Attack
Columbia Engineering researchers led by Associate Professor Tal Danino have developed the CAPPSID system, which engineers Salmonella typhimurium bacteria to carry Senecavirus A directly into tumor cells. The bacteria serve as protective vehicles, shielding the cancer-killing virus from circulating antibodies that would normally neutralize viral therapies. Once inside the tumor, the bacteria release their viral payload, which then infects and destroys cancer cells from within.
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Overcoming Immune System Dependencies
Traditional immunotherapies like checkpoint inhibitors and CAR-T cell treatments rely heavily on patients having robust immune systems, leaving many cancer patients without viable treatment options. The CAPPSID approach circumvents this limitation by using bacteria as delivery vehicles that can operate independently of immune function. Co-lead author Zakary Singer explains that bacteria act as an “invisibility cloak, hiding the virus from circulating antibodies, and ferrying the virus to where it is needed.”
Building on Historical Cancer Treatment Methods
The research builds upon William Coley’s pioneering work from the 1890s, when bacterial infections were first observed to shrink tumors. However, early bacterial therapies faced significant limitations due to their dependence on immune system activation. The Columbia team’s innovation combines bacterial tumor-targeting capabilities with viral cancer cell destruction, creating what researchers describe as the first directly engineered cooperative system between bacteria and oncolytic viruses.
Clinical Promise for Excluded Patients
The CAPPSID system has demonstrated successful tumor targeting and destruction in mouse models, with engineered safeguards preventing viral spread outside tumor areas. This breakthrough particularly benefits immunocompromised patients who cannot access immune-dependent therapies. The research team, including collaborators from Rockefeller University, published their findings in Nature Biomedical Engineering and anticipates clinical trials following regulatory review.
Singer emphasizes that their goal extends beyond single treatments: “Our objective is to open a path toward multi-organism therapies that can accomplish far more than any single microbe could achieve alone.” This approach represents a significant advance in synthetic biology applications for cancer treatment, potentially establishing an entirely new class of cooperative microbial therapeutics that could transform oncology care for patients previously excluded from cutting-edge treatments.
Sources:
Virus Cloaked in Bacteria Kills Tumor Cells from Within
Trojan horse bacteria sneak cancer-killing viruses into tumors
Cancer breakthrough: New bacteria cancer treatment kills tumours without immune system support
