Bacteria-based immunosuppressive tumor microenvironment reprogramming: a promising dawn in cancer therapy.

Traditional chemotherapy, a prevalent cancer treatment modality, is associated with significant side effects and often leads to treatment failure. Non-specific drug distribution and chemoresistance are the main factors contributing to this failure. Certain distinctive characteristics of the tumor microenvironment (TME), including hypoxia, acidic pH, and increased interstitial fluid pressure, render cancer cells resistant to conventional treatments. Multiple approaches have been devised to enhance the treatment efficiency of neoplasms and overcome chemoresistance. Nowadays, bacteria-based cancer therapy has garnered significant interest in both preclinical and clinical research, owing to its distinctive mechanism and various applications in eliciting host antitumor immunity. Due to their inherent tumor tropism, elevated motility, and capacity for quick colonization in the conducive TME, bacteria are increasingly being considered for targeted tumor treatment. Bacteria, rich in pathogen-associated molecular patterns (PAMPs), can efficiently stimulate immune cells even inside the immunosuppressive TME, boosting the particular immune detection and eradication of tumor cells. Furthermore, outer membrane vesicles (OMVs), cytoplasmic membrane vesicles (CMVs), and their derived physiological components exhibit analogous functionalities to their parental cells. This review article is representative of the latest innovations in bacteria-based immunosuppressive TME reprogramming. Additionally, the article discusses future directions in this research area, drawing on current advances.