Salmonella typhimurium may support cancer treatment: a review

Abstract

Antitumour treatments are evolving, including bacteria-mediated cancer therapy which is concurrently an ancient and cutting-edge approach. Salmonella typhimurium is a widely studied bacterial species that colonizes tumor tissues, showing oncolytic and immune system-regulating properties. It can be used as a delivery vector for genes and drugs, supporting conventional treatments that lack tumor-targeting abilities. This article summarizes recent evidence on the anticancer mechanisms of S. typhimurium alone and in combination with other anticancer treatments, suggesting that it may be a suitable approach to disease management.

Keywords: bacteria-mediated cancer therapy (BMCT); bacterial delivery vector; bactofection; combination therapy; tumor therapy.

Figure 1

Main advantages in cancer treatment of Salmonella typhimurium ST tends to colonize in multiple tumor tissues and can induce a series of anti-cancer immune responses. ST is also an ideal tumor-targeting vector which can deliver almost everything to tumor tissues.

Figure 2

Examples of different mechanisms followed by Salmonella typhimurium for cancer therapy ST can increase multiple innate and adaptive immune cells like CD8+ T cells, NK cells and macrophages, it also reduces Treg cells in TME. Upregulation and activation of Cx43 expression by ST enhances antigen delivery in dendritic cells and facilitates the delivery of chemotherapeutic drugs and apoptotic signals within cancer cells. Using gene-modified strains, drug-loaded liposomes or OMVs carrying drugs/pro-drugs, anti-tumor genes/drugs can be delivered directly into tumor tissues by ST. Plasmid carrying cytosine deaminase can convert non-toxic 5-fluorocytosine (5-FC) to 5-fluorouracil (5-FU). This approach limits the toxicity of chemotherapeutic drugs to the tumor area.