A biohybrid system using probiotic bacteria to deliver the anticancer peptide ruxotemitide directly to tumors triggered pyroptosis and activated anti-tumor immunity in mice without systemic toxicity.
Living bacteria + anticancer peptideProbiotic E. coli Nissle 1917 engineered to carry LTX-315-loaded nanoparticles accumulated in tumors and activated anti-tumor immunity through pyroptosis
What the researchers found
A bacteria-based biohybrid system (P/L@EcN) combining the probiotic E. coli Nissle 1917 with nanoparticles loaded with the anticancer peptide ruxotemitide (LTX-315) successfully suppressed tumor growth in a mouse breast cancer model. The system achieved enhanced tumor accumulation and penetration, triggered cancer cell death through pyroptosis (caspase-1-dependent), remodeled the tumor immune environment by boosting M1 macrophages and reducing immune-suppressive MDSCs, and showed no systemic toxicity.
Why it matters
This study demonstrates a creative approach to cancer immunotherapy: using bacteria as living delivery vehicles for anticancer peptides. By combining bacterial tumor-targeting ability with a peptide that triggers inflammatory cancer cell death (pyroptosis), the system activates the immune system against tumors in a way that neither component could achieve alone.
The numbers in context
Peptide: ruxotemitide (LTX-315) · Bacteria: E. coli Nissle 1917 · Improved M1/M2 macrophage ratio · Reduced MDSCs · No systemic toxicity
How the study worked
Researchers created a biohybrid by conjugating ROS-responsive, peptide-loaded PEG-PLGA nanoparticles to tumor-targeting probiotic E. coli Nissle 1917 using copper-free click chemistry. The system was tested for tumor accumulation, cellular uptake, tumor penetration, and pyroptosis induction in vitro, then evaluated in an orthotopic breast cancer mouse model for anti-tumor efficacy and immune remodeling.
Who was studied
BALB/c mice with orthotopic breast cancer tumors; in vitro tumor cell lines
What this study cannot tell us
Mouse study with a single tumor type (orthotopic breast cancer). Long-term safety of introducing engineered bacteria into patients is unknown. Clinical translation of bacteria-based delivery systems faces major regulatory hurdles. Specific quantitative results (tumor size reduction percentages, survival data) not detailed in abstract.
How to read the evidence
This is an early-stage animal study using a mouse breast cancer model. While the results are promising, the system has not been tested in humans and faces significant translational challenges including the safety of introducing engineered bacteria.
When this study was published
Published in 2025, this is a very recent study at the cutting edge of bacteria-based cancer therapy and peptide drug delivery research.
The bigger picture
Cancer immunotherapy has been revolutionized by checkpoint inhibitors and CAR-T cells, but many tumors remain resistant because their microenvironment suppresses immune responses. This bacteria-peptide hybrid represents a new frontier: using engineered living organisms to deliver immunogenic peptides directly into tumors, potentially converting 'cold' tumors that evade immunity into 'hot' ones that the immune system can attack.
Questions still open
- Can bacteria-based peptide delivery systems be safely used in humans, given concerns about introducing live bacteria?
- Would this approach work against tumor types beyond breast cancer, particularly 'cold' tumors that resist current immunotherapies?
- How does ruxotemitide-induced pyroptosis compare to other forms of immunogenic cell death for sustained anti-tumor immunity?
Common questions
What is pyroptosis and why is it useful for fighting cancer?
Is it safe to use bacteria to deliver drugs to tumors?
Read the original research
Bacteria biohybrids integrating anticancer peptide-loaded nanoparticles for tumor immunotherapy through pyroptosis activation.
Biomaterials science, 13(22), 6423-6432
Citation
Chen, Shiyi; Ouyang, Xunping; Wei, Xue; He, Gang; Xian, Yiwen; Zhang, Chong; Wu, Decheng. (2025). Bacteria biohybrids integrating anticancer peptide-loaded nanoparticles for tumor immunotherapy through pyroptosis activation.. Biomaterials science, 13(22), 6423-6432. https://doi.org/10.1039/d5bm00667h