Engineered Bifidobacterium Strains Colonization at Tumor Sites: A Novel Approach to the Delivery of Cancer Treatments

Bacteria-mediated cancer therapy represents a novel and promising strategy for targeted drug delivery to solid tumors. Multiple studies have demonstrated that various Bifidobacterium species can selectively colonize the hypoxic microenvironments characteristic of solid tumors. Leveraging this property, Bifidobacterium has been explored as a delivery vector for a range of anti-cancer approaches such as immunotherapy, nanoformulated chemotherapeutics, and gene therapy. Notably, anti-angiogenic genes such as endostatin and tumstatin have been successfully delivered to colorectal tumors using Bifidobacterium infantis and Bifidobacterium longum, respectively. Additionally, Bifidobacterium bifidum has been employed to transport doxorubicin and paclitaxel nanoparticles to breast and lung tumor sites. Furthermore, both Bifidobacterium longum and Bifidobacterium bifidum have been utilized to deliver nanoparticles that act as synergistic agents for high-intensity focused ultrasound (HIFU) therapy, significantly enhancing tumor ablation, particularly in triple-negative breast cancer (TNBC) models. While these pre-clinical findings are highly encouraging, further clinical research is essential. Specifically, studies are needed to investigate the colonization dynamics of different Bifidobacterium species across various tumor types and to evaluate their potential in delivering diverse cancer therapies in human patients.