Bacteria‐Based Cancer Immunotherapy

Abstract

In the past decade, bacteria‐based cancer immunotherapy has attracted much attention in the academic circle due to its unique mechanism and abundant applications in triggering the host anti‐tumor immunity. One advantage of bacteria lies in their capability in targeting tumors and preferentially colonizing the core area of the tumor. Because bacteria are abundant in pathogen‐associated molecular patterns that can effectively activate the immune cells even in the tumor immunosuppressive microenvironment, they are capable of enhancing the specific immune recognition and elimination of tumor cells. More attractively, during the rapid development of synthetic biology, using gene technology to enable bacteria to be an efficient producer of immunotherapeutic agents has led to many creative immunotherapy paradigms. The combination of bacteria and nanomaterials also displays infinite imagination in the multifunctional endowment for cancer immunotherapy. The current progress report summarizes the recent advances in bacteria‐based cancer immunotherapy with specific foci on the applications of naive bacteria‐, engineered bacteria‐, and bacterial components‐based cancer immunotherapy, and at the same time discusses future directions in this field of research based on the present developments.

Endocrine and Neuroendocrine Tumors Special Issue—Checkpoint Inhibitors for Adrenocortical Carcinoma and Metastatic Pheochromocytoma and Paraganglioma: Do They Work?

“…Pseudomonas aeruginosa is a Gram-negative bacterium, characterized by the presence of lipopolysaccharides in the outer layer and many other components that trigger or enhance an immune response. These bacteria may become trapped in the tumor microenvironment within the abnormal vessels, inducing an immune attack against tumor cells, thus supporting bacteria-based MPPGL immunotherapy [74,75].…”

Trojan bacteria cross blood-brain barrier for glioblastoma photothermal immunotherapy

“…Under 808-nm irradiation, the ICG molecules loaded on SiNPs could convert light energy into the su cient heat to lysis host bacterial cells and destruct tumour cells. As a result, a pool of tumour-associated antigens and bacterial residues could together promote antitumor immune responses [47][48][49][50][51] . Typically, immature dendritic cells (iDCs) recognize tumour-associated antigens and bacterial residues through pattern recognition receptors and become mature DCs (mDCs).…”

Bacterially Synthesized Tellurium Nanorods for Elimination of Advanced Malignant Tumor by Photothermal Immunotherapy

“…These data verified that Te@EcN administered systemically could efficiently accumulate and retain in tumors, and be rapidly metabolized and eliminated in normal organs. Based on a few reports on tumor targeting of live bacteria, [4,54,55] we speculated that the tumor targeting mechanism of Te@ EcN with no motility and proliferation ability might be as follows: Te@EcN might initially be passively trapped in the chaotic tumor vasculature; the sharp increase in TNF-α induced by bacterial infection would cause severe tumor vascular destruction; then, Te@EcN could be flushed into the tumor with the blood flow and accumulate within the tumor. To verify the hypothesis, we have collected the 4T1 tumors of mice at 24 h after intravenous injection of PBS or Te@EcN at the Te dose of 0.8 mg kg −1 .…”

“…[3] Some anaerobes have been found to preferentially colonize in the tumor tissues after systemic administration, which is thought to be related to the chaotic vasculature, hypoxia, immunosuppression, and eutrophication of solid tumors. [3,4] Additionally, due to the immunogenicity of bacterial components such as lipopolysaccharide (LPS) and flagellin, localized bacterial infection can induce host immune responses and remodel the tumor immune microenvironment, thus leading to antitumor effects. [5,6] Nevertheless, the attenuated Salmonella typhimurium named VNP20009 showed good safety and antitumor activity in animal studies, but failed in a phase I clinical trial due to low tumor regression and undesired dose-dependent side effects.…”