Researchers at Washington University School of Medicine have engineered a yeast-based probiotic that delivers immunotherapy directly to tumors in the gut, potentially offering a new oral treatment option for gastrointestinal cancers.

While oral immunotherapy could effectively target these cancers, traditional protein-based treatments often degrade in the harsh gut environment; however, probiotics can survive these conditions and transport drugs safely.

The specific probiotic utilized in this study is Saccharomyces cerevisiae var. boulardii, a safe yeast strain known for its anticancer properties and ability to maintain gut microbial balance.

This engineered yeast functions as a drug factory, producing immune checkpoint inhibitors that stimulate the immune system to recognize and attack cancer cells.

Immunotherapy has shown promise for cancer treatment, but its success in gastrointestinal cancers has been limited due to the difficult-to-reach locations of these tumors.

The study presents a novel approach to enhance the delivery of immunotherapy, potentially expanding treatment options for these challenging cancers.

Late-stage detection of gastrointestinal cancers is common due to anatomical challenges, resulting in high mortality rates and often necessitating combination therapies such as surgery and chemotherapy.

Gastrointestinal cancers, which include stomach, liver, esophageal, pancreatic, and colorectal cancers, account for over 25% of all cancer cases globally, affecting more than 5 million people and leading to approximately 3.7 million deaths annually.

Current immunotherapy options for these cancers are limited and typically require intravenous delivery, which often results in reduced effectiveness at tumor sites.

The study, published in the journal Cell Chemical Biology, introduces a customizable drug delivery system that could also be applied to treat other gut diseases.

The research team has filed two patents for their engineered probiotic and is exploring its application in treating other gastrointestinal diseases, including Clostridioides difficile infections.

Gautam Dantas, Ph.D., the senior author, emphasizes the significant challenges posed by the complex anatomical locations of gastrointestinal cancers.