At a Glance
- A new cancer therapy called AUN uses a consortium of two natural bacteria to eradicate tumors in both immunocompetent and immunocompromised mouse models without systemic toxicity.
- The treatment works independently of the immune system, making it a promising option for patients whose immune functions are weakened by chemotherapy or radiotherapy.
- Mechanistically, the bacterial duo selectively destroys tumor blood vessels, forms biofilms within the cancer, and exerts direct oncolytic effects, leading to widespread tumor necrosis.
- One bacterium, UN-gyo, modulates the activity of its partner, A-gyo, enhancing safety and promoting a cancer-specific transformation that boosts its antitumor potency inside the tumor.
- Led by JAIST, the research team plans to launch a startup and aims to initiate clinical trials within six years, bringing this novel therapy to patients.
Japanese researchers have developed a groundbreaking cancer therapy that uses a two-bacteria team to destroy tumors without relying on the body’s immune system. This new approach, named AUN therapy, offers a potential lifeline for cancer patients with compromised immune systems who cannot benefit from modern immunotherapies. The study, led by Professor Eijiro Miyako of the Japan Advanced Institute of Science and Technology in collaboration with Daiichi Sankyo Co., Ltd. and the University of Tsukuba, was published in the journal Nature Biomedical Engineering.
The AUN therapy consists of a precise mixture, or consortium, of two naturally occurring bacteria: Proteus mirabilis (A-gyo) and the photosynthetic Rhodopseudomonas palustris (UN-gyo). Unlike treatments such as checkpoint inhibitors or CAR-T cells that require a robust immune response to attack cancer, AUN works directly on the tumor. When administered intravenously in mouse models with both murine and human cancers, the bacterial consortium achieved complete tumor remission and prolonged survival, even in immunocompromised subjects, demonstrating its potential for patients weakened by chemotherapy or radiotherapy.
The therapy’s success lies in the unique synergy between the two bacteria. Once inside the body, the consortium selectively targets tumors, triggering the formation of blood clots, or thrombosis, within the tumor’s blood vessels. This cuts off the tumor’s blood supply, causing it to die from the inside out in a process called necrosis. In a remarkable display of adaptation, the initial 3:97 bacterial ratio of A-gyo to UN-gyo shifts dramatically to 99:1 within the tumor, optimizing its cancer-killing potency. At the same time, UN-gyo acts as a built-in safety control, suppressing toxicity and preventing dangerous side effects, such as cytokine release syndrome.
This research represents a significant advancement in a field that began over 150 years ago with early attempts to utilize bacteria in the fight against cancer. By harnessing a natural partnership between microbes without the need for genetic engineering, the team has created a self-regulating and highly targeted therapeutic. “To accelerate the social implementation of this research, we are preparing to launch a startup and aim to begin clinical trials within six years,” Professor Miyako said in an institutional press release. This work could usher in a new era of cancer treatment, offering hope where conventional immunotherapies fall short.
References
- Iwata, S., Nishiyama, T., Sakari, M., Doi, Y., Takaya, N., Ogitani, Y., Nagano, H., Fukuchi, K., & Miyako, E. (2025). Tumour-resident oncolytic bacteria trigger potent anticancer effects through selective intratumoural thrombosis and necrosis. Nature Biomedical Engineering. https://doi.org/10.1038/s41551-025-01459-9
- Japan Advanced Institute of Science & Technology. (2025, August 5). Bacterial duo eliminates tumors without immune system help in new cancer therapy. Medical Xpress; Japan Advanced Institute of Science and Technology. https://medicalxpress.com/news/2025-08-bacterial-duo-tumors-immune-cancer.html
