A groundbreaking study from Columbia University has introduced a novel way to fight cancer: using engineered bacteria to smuggle therapeutic viruses directly into tumors. This engineered system, known as CAPPSID (Coordinated Activity of Prokaryote and Picornavirus for Safe Intracellular Delivery), represents the first successful demonstration of bacteria and viruses working together to selectively target cancer cells and limit systemic colonization outside the tumor environment.

The Discovery Explained

At the heart of this breakthrough is a carefully designed collaboration between two biological agents. Engineered Salmonella Typhimurium, a strain previously studied in bacteria-based immunotherapy and bacterial vaccines, acts as a Trojan horse, homing in on tumors and shielding the virus from immune detection. Inside these bacteria, researchers loaded Senecavirus A (SVA)—an oncolytic viral infection candidate that replicates selectively in cancer cells.

The virus was genetically tuned so its viral replication and viral maturation depend on a protease produced by the bacteria. This means viral proteins cannot form and viral genomes cannot amplify until the bacteria are inside the tumor. The result: targeted release of the virus and minimized viral spread to healthy tissues. In mouse model experiments approved by the Institutional Animal Care and Use Committee and conducted in partnership with Charles River, tumors were significantly reduced. Measurements using digital calipers and imaging of GFP reporter signal confirmed tumor regression and effective viral RNA production within the tumor microenvironment.

Supporting this discovery were essential research tools, including LB agar cultures to grow bacteria, RNA extraction protocols to measure viral output, and Nanopore sequencing to verify engineered viral genomes. Tissue analysis involved dissociation with a tissue dissociator and smFISH staining to visualize viral activity in situ. These techniques underscore the complexity and precision behind modern microbial therapies.

Why It Matters

This study addresses one of the most significant challenges in cancer virotherapy: immune neutralization. By cloaking the virus within tumor-seeking bacteria, the team overcame immune clearance, allowing viral replication to occur exactly where it is needed. The result is a clinical translation-ready blueprint that integrates bacterial therapeutics and oncolytic viral infection into one system. If taken forward into clinical trials, this approach could open a new era for bacteria-based immunotherapy and targeted cancer treatment.

Final Thoughts

The CAPPSID system highlights how combining bacterial carriers with oncolytic viruses can unlock new frontiers in cancer therapy. As researchers, we continue to refine this approach and publish findings in journals, the need for reliable laboratory infrastructure remains crucial.

This is where MSE Supplies plays its part. We provide scientists with the cell culture systems, imaging tools, and molecular biology equipment that make complex experiments possible — from growing S. Typhimurium colonies to analyzing homogenized tissues for viral RNA output. Rather than building therapies, we empower the labs that create them.

Explore our collection of lab equipment and materials to see how MSE Supplies can support your next discovery. Stay connected by visiting our website, following us on LinkedIn, and subscribing to our newsletter for more insights into the science shaping tomorrow’s breakthroughs.

Source:

1. Singer, Z. S., Pabón, J., Huang, H., Sun, W., Luo, H., Grant, K. R., Obi, I., Coker, C., Rice, C. M., & Danino, T. (2025). Engineered bacteria launch and control an oncolytic virus. Nature Biomedical Engineering. https://doi.org/10.1038/s41551-025-01476-8