Bacteria-driven therapies are an exciting advancement in the realm of cancer treatment, utilizing their unique capability to accurately identify and combat tumors. To effectively leverage this strategy, a safe and efficient method for generating natural anticancer bacteria is essential. Recently, researchers from Japan have introduced an innovative scaffold-based technique to cultivate these antitumor bacteria. This new approach not only boosts the tumor-fighting effectiveness and safety of the bacteria but also offers a straightforward solution for large-scale production.
Bacteria-driven therapies are an exciting advancement in the realm of cancer treatment, utilizing their unique capability to accurately identify and combat tumors. To effectively leverage this strategy, a safe and efficient method for generating natural anticancer bacteria is essential. Recently, researchers from Japan have introduced an innovative scaffold-based technique to cultivate these antitumor bacteria. This new approach not only boosts the tumor-fighting effectiveness and safety of the bacteria but also offers a straightforward solution for large-scale production.
Despite cancer being a leading global cause of death, therapies based on bacteria offer a promising and innovative treatment avenue. Bacteria have the natural ability to infiltrate the tough protective barrier of tumors, allowing them to effectively target solid tumors. However, before bacteria can be utilized for medical treatments, several crucial considerations must be addressed. For clinical trials, bacteria must be rendered less virulent or “attenuated” to ensure safe application in animals and humans. Moreover, a straightforward manufacturing process is essential to produce both safe and effective anticancer bacteria, which necessitates the creation of an optimal culturing technique.
In a recent study published in the Chemical Engineering Journal, researchers from the Japan Advanced Institute of Science and Technology (JAIST), led by Professor Eijiro Miyako and including Mikako Miyahara in collaboration with the University of Tsukuba, have created a groundbreaking method to culture antitumor bacteria through the use of highly porous scaffolds. This innovative technique not only boosts the cancer-fighting capabilities of the bacteria but also enhances its safety during animal testing.
Previously, the research team isolated two types of bacteria, A-gyo and UN-gyo, from tumors in laboratory mice. A-gyo refers to the bacterium Proteus mirabilis while UN-gyo denotes the photosynthetic bacterium Rhodopseudomonas palustris. These bacteria reside within tumor cells, interacting with them and potentially impacting tumor growth and treatment response. Together, they form the ‘AUN bacterial consortium’, which shows considerable potential as an effective tool for cancer detection due to its ability to accurately target tumors and its safety profile. However, cultivating these bacteria in the best possible manner proved to be a challenge.
To effectively culture AUN, the researchers turned to specially designed scaffolds. They created a microporous scaffold using a biocompatible polymer called polydimethylsiloxane (PDMS) combined with titanium dioxide (TiO2). Incorporating TiO2 established a balance, enabling the bacteria to target tumors effectively while preventing excessive bacterial growth that could lead to unintended infections or immune reactions. These porous scaffolds significantly enhanced the anticancer properties of the bacteria, making them more potent.
After preparing the PDMS-TiO2 composite, the researchers cultured AUN bacteria alongside the scaffold pieces while exposing the entire setup to light. They discovered that, under light exposure, TiO2 within the scaffold effectively diminished the bacteria’s virulence by generating toxic molecules known as reactive oxygen species (ROS), thereby ensuring safety during treatments.
Following this, the team assessed the anticancer effectiveness of AUN. They were surprised to find that AUN cultured with scaffolds demonstrated a higher capability to eliminate various types of tumor cells. In experiments with mice suffering from breast cancer, the treatment with attenuated AUN bacteria resulted in better survival rates. The mice with drug-resistant breast cancer showed increased anticancer activity as well.
“We found that the robust anticancer response stemmed from the oncolytic (tumor-killing) abilities of AUN, aided by a range of activated immune cells such as T cells, NK cells, and macrophages in the tumor microenvironment,” stated Mikako Miyahara, a doctoral candidate at JAIST and the primary author of the study. The research also confirmed that AUN, grown using scaffolds, could be safely administered not only to mice but also to dogs.
With improved safety and effectiveness from this uncomplicated technique, AUN is getting closer to being widely used in cancer therapies. The researchers anticipate that this technology will enter clinical trials within the next decade.
“Our findings on how porous scaffolds affect the bacterial behavior of AUN will assist in designing artificial scaffold materials for effective treatment against drug-resistant cancers,” highlighted Prof. Miyako. In conclusion, this pioneering study prepares the path for the future commercialization and clinical application of AUN, providing renewed hope for patients faced with various forms of cancer.
