More than a century ago, Dr. William B. Coley laid the groundwork for modern immunotherapy by injecting cancer patients with bacterial toxins in an effort to reduce tumors. In a groundbreaking development, researchers in Japan have now gone a step further by targeting cancer in mice without relying on the immune system. They have introduced a newly engineered bacterial cancer therapy that operates independently of the immune system, leading to complete tumor remission in both immunocompetent and immunocompromised mice.
While immunotherapies like CAR-T cells and checkpoint inhibitors have transformed cancer treatment, they necessitate a functioning immune system to be effective, posing a significant challenge for patients undergoing chemotherapy or radiation who are often immunocompromised. Scientists from the Japan Advanced Institute of Science and Technology (JAIST), Daiichi Sankyo, and the University of Tsukuba have developed a bacterial consortium named AUN, which exhibits potent antitumor effects in mouse models, even in the absence of functional immune cells. Their research, published in Nature Biomedical Engineering, presents a promising immune-independent strategy for cancer therapy that could particularly benefit immunocompromised patients.
The AUN therapy consists of two naturally occurring bacteria: Proteus mirabilis (A-gyo), a non-pathogenic microbe residing in tumors with limited motility, and Rhodopseudomonas palustris (UN-gyo), a photosynthetic bacterium that boosts A-gyo’s specificity and safety. Administered intravenously in a specific 3:97 ratio (A-gyo:UN-gyo), this bacterial combination accumulates within tumors, inducing selective intratumoral thrombosis, vascular collapse, platelet aggregation, and extensive tumor necrosis, all without causing systemic toxicity or cytokine release syndrome. The therapy was tested across various mouse models, including colorectal cancer, sarcoma, metastatic lung cancer, and drug-resistant triple-negative breast cancer.
Notably, the researchers observed a high rate of complete responses in immunocompromised mice treated with AUN, even against human tumor xenografts. The destruction of tumor spheroids by AUN-secreted cytolysins was a key factor in this outcome, suggesting a novel approach to tumor eradication without the need for genetic engineering. The controllability of AUN utilizing antibiotics adds to its appeal, although concerns regarding potential drug resistance and infection risks associated with live bacteria usage require careful consideration.
The study marks a significant shift in cancer therapy, showcasing that bacteria alone, without immune assistance, can eradicate tumors through localized vascular shutdown and direct cytotoxicity. Researchers are optimistic about the future potential of AUN and are planning to establish a startup with the aim of commencing clinical trials in the next six years. Lead author Dr. Eijiro Miyako envisions a new era in bacteria-based cancer treatment, offering hope for effective therapies in patients with compromised immune systems.
Key Takeaways:
– The AUN bacterial therapy showcases immune-independent tumor destruction in mouse models, presenting a promising avenue for cancer treatment in immunocompromised individuals.
– By leveraging a specific bacterial consortium, AUN triggers localized vascular shutdown and tumor necrosis without requiring immune system activation.
– The controllability of AUN through antibiotics enhances its safety profile, although potential concerns regarding drug resistance and infection risks must be addressed.
– This study represents a significant advancement in bacteria-based cancer therapy, highlighting the potential for a new era in treatment strategies for patients with compromised immune systems.
Tags: immunotherapy, biotech
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