New Bacterial Therapy Shown to Eliminate Cancer Without Immune System Involvement: Study

The findings have been published in Nature Biomedical Engineering.

The AUN therapy combines two naturally occurring bacteria: Proteus mirabilis (A-gyo), which naturally lives inside tumors, and Rhodopseudomonas palustris (UN-gyo), a photosynthetic bacterium. When injected into tumors, these bacteria work together in a carefully balanced partnership. Initially, the tumor contains about 3% A-gyo and 97% UN-gyo, but this ratio shifts dramatically to 99% A-gyo as the treatment progresses, maximizing the destruction of cancer cells.

A-gyo attacks tumors by destroying cancer cells and cutting off their blood supply. It undergoes a structural change triggered by tumor metabolites that boosts its cancer-killing power. Meanwhile, UN-gyo regulates A-gyo’s activity, preventing uncontrolled bacterial growth and reducing harmful side effects. This balance and cooperation between the two bacteria reflect the Japanese concept of "AUN," symbolizing harmony between opposites.

In tests on mice and human tumor models, AUN therapy effectively eliminated tumors even when immune function was impaired. It showed minimal side effects and avoided dangerous immune reactions common in other bacterial therapies.

The research team is advancing AUN toward clinical trials, hoping to bring this immune-independent therapy to patients within six years. This novel treatment could transform cancer care, especially for those unable to tolerate or respond to current immune-based therapies, offering a new path toward lasting tumor eradication.

REFERENCE: Seigo Iwata, Taisei Nishiyama, Matomo Sakari, Yuki Doi, Naoki Takaya, Yusuke Ogitani, Hiroshi Nagano, Keisuke Fukuchi, Eijiro Miyako. Tumour-resident oncolytic bacteria trigger potent anticancer effects through selective intratumoural thrombosis and necrosis. Nature Biomedical Engineering, 2025; DOI: 10.1038/s41551-025-01459-9