Cancer remains one of the world’s biggest health challenges. Over the past few decades, scientists have developed many new treatments that help the body’s own immune system find and destroy cancer cells.
These treatments, known as immunotherapies, have changed the lives of many patients and have become an important part of modern cancer care. However, there is one major problem.
Many of these treatments depend on a strong and healthy immune system. For people whose immune systems have been weakened by chemotherapy, illness, age, or other factors, these treatments may not work well enough.
Now, researchers in Japan have developed a promising new approach that could offer hope to these patients. The treatment does not rely on the immune system to fight cancer. Instead, it uses two different kinds of bacteria that work together to attack tumors directly.
The research was led by Professor Eijiro Miyako from the Japan Advanced Institute of Science and Technology (JAIST). He worked with scientists from Daiichi Sankyo Co., Ltd. and the University of Tsukuba. Their findings were published in the journal Nature Biomedical Engineering.
The idea of using bacteria to treat cancer is not entirely new. More than 150 years ago, doctors noticed that some cancer patients improved after developing bacterial infections. In the late 1800s, a German doctor named Busch reported that a patient’s cancer became smaller after a bacterial infection.
A few years later, American surgeon Dr. William Coley developed one of the first bacterial cancer treatments. His work later inspired the development of modern immunotherapy.
Although today’s cancer treatments are far more advanced, many still share the same weakness. They need the immune system to play an active role. If the immune system is not working properly, treatment success can be limited.
The new treatment, called AUN therapy, was designed to solve this problem. It uses two naturally occurring bacteria that perform different jobs while working together as a team. One bacterium is called Proteus mirabilis, which the researchers named A-gyo. The other is Rhodopseudomonas palustris, named UN-gyo.
The name AUN comes from a traditional Japanese concept that represents harmony and balance between two complementary forces. This idea is reflected in the way the bacteria work together.
A-gyo is the main cancer-fighting bacterium. It naturally prefers the environment inside tumors. Once it enters a tumor, it changes its form and becomes more effective at destroying cancer cells. This allows it to directly attack the tumor without needing help from the immune system.
UN-gyo plays a different but equally important role. It supports the activity of A-gyo and helps control its behavior. By doing this, it reduces the risk of excessive damage and helps make the treatment safer.
At the beginning of treatment, UN-gyo makes up most of the bacterial mixture. However, after the bacteria enter the tumor, conditions inside the cancer cause the balance to shift. A-gyo becomes the dominant bacterium and takes the lead in attacking cancer cells. This natural change allows the therapy to become stronger exactly where it is needed most.
One of the most encouraging findings is the treatment’s safety profile. Many powerful cancer therapies can cause serious side effects.
Some immunotherapies can trigger a dangerous reaction known as cytokine release syndrome, in which the immune system becomes overactive and causes widespread inflammation. According to the researchers, AUN therapy avoids this problem because it does not depend on stimulating the immune system.
The bacteria also appear to respond to conditions inside tumors, allowing the treatment to target cancer more precisely. This may help reduce harm to healthy tissues while improving the effectiveness of the therapy.
The researchers believe their discovery could represent a major step forward in cancer treatment. By combining two bacteria with different strengths, they created a system in which one bacterium attacks cancer while the other helps maintain balance and safety. This partnership allows the treatment to function even when the immune system is weakened.
Professor Miyako and his team are now working toward the next stage of development. They plan to establish a startup company to help advance the technology and hope to begin human clinical trials within the next six years.
If future studies confirm the early results, AUN therapy could provide a new option for cancer patients who currently have limited treatment choices. It may also open a new chapter in the long history of bacterial cancer therapy, showing how natural biological systems can be harnessed in innovative ways to fight disease.
While more research is still needed before the treatment becomes widely available, the findings offer fresh hope. For patients whose immune systems cannot fully support existing therapies, this two-bacteria approach could one day become an important new weapon in the fight against cancer.
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