Bacteria may be the next frontier in cancer treatment, according to a team led by researchers at Penn State that devised a new approach of creating bacteria-derived mixtures - or cocktails - to help fight bladder cancer. They tested their mixtures of good and bad bacteria on patient tumor samples and in mice, finding that the cocktails significantly boost the immune system's ability to fight cancer.
The researchers explained how the approach, detailed in a paper published today (Dec. 2) in Nature Communications, could be personalized to a patient's specific health needs, while delivering more efficient treatment at a cost comparable to, or lower than, existing cancer treatment options.
According to lead author Pak Kin Wong, professor of biomedical engineering and of mechanical engineering at Penn State, one of the most promising approaches to treating cancer is immunotherapy, where doctors use a patient's immune system to target cancer cells. In bladder cancer, doctors can introduce live bacteria into a patient's body to engage their immune system in the fight against cancerous cells. This approach, called bacillus Calmette-Guérin (BCG) immunotherapy, was originally reported in the 1976 and is still the only approved method of bacterial immunotherapy for use in the clinic, Wong said. Despite its singular status, Wong explained it still has much room for optimization.
"People have recognized the connection between bacterial infection and cancer regression since the 1800s," Wong said, noting that it still took more than a century for that understanding to transform into an actual treatment with BCG. "However, this type of immunotherapy, which relies on a single bacterial type, works for only a portion of patients. We now know that our immune system interacts with thousands of different kinds of bacteria every day, which opens many new possibilities and can help make treatments more effective."
The new approach, which the team calls microbial product cocktail (MPC) immunotherapy, uses microbial products derived from bacteria instead of the live, whole bacteria used in BCG immunotherapy. Wong explained how using these products allows researchers to have more control during treatment and, in turn, test more bacterial mixtures without the risk of harmful bacteria making patients sick. To decide the specific mixtures of products used, the researchers developed an artificial intelligence (AI) model that optimizes both the composition and relative dosage of microbial products, testing these AI-optimizedcocktails in tumor organoids - mini-tumors derived from a patient's tumor tissues - to evaluate how well each cocktail activated the patient's immune response. This approach allows the MPC immunotherapy to be personalized for each individual patient.
