Bacterial Drug Delivery Systems for Cancer Therapy: “Why” and “How”

Abstract

Cancer is one of the major diseases that endanger human health. However, the use of anticancer drugs is accompanied by a series of side effects. Suitable drug delivery systems can reduce the toxic side effects of drugs and enhance the bioavailability of drugs, among which targeted drug delivery systems are the main development direction of anticancer drug delivery systems. Bacteria is a novel drug delivery system that has shown great potential in cancer therapy because of its tumor-targeting, oncolytic, and immunomodulatory properties. In this review, we systematically describe the reasons why bacteria are suitable carriers of anticancer drugs and the mechanisms by which these advantages arise. Secondly, we outline strategies on how to load drugs onto bacterial carriers. These drug-loading strategies include surface modification and internal modification of bacteria. We focus on the drug-loading strategy because appropriate strategies play a key role in ensuring the stability of the delivery system and improving drug efficacy. Lastly, we also describe the current state of bacterial clinical trials and discuss current challenges. This review summarizes the advantages and various drug-loading strategies of bacteria for cancer therapy and will contribute to the development of bacterial drug delivery systems.

Drug-Loaded Biomimetic Carriers for Non-Hodgkin’s Lymphoma Therapy: Advances and Perspective

“…When administered systemically bacteria can use their biomigratory ability to distribute to areas of tumor tissue that are more suitable for survival and reproduction. 75 Studies in the field confirm that Salmonella colonies start accumulating within the tumor region merely 3 days after the systemic administration of the drug. 64 These combined cancer therapies showcase distinct attributes:…”

“…The inherent biomigratory ability of bacteria allows them to target tumors more accurately than the passive distribution and limited penetration capacity of chemotherapeutic agents as well as the durable and efficient transport capacity as an organism that can derive energy from its surroundings for further reproduction. When administered systemically bacteria can use their biomigratory ability to distribute to areas of tumor tissue that are more suitable for survival and reproduction . Studies in the field confirm that Salmonella colonies start accumulating within the tumor region merely 3 days after the systemic administration of the drug .…”

Long-Term Tumor-Targeting Effect of E. coli as a Drug Delivery System

“…These living, motile bacteria, equipped with surface appendages like flagella and pili, display a variety of movement behaviors. These include swimming, swarming, twitching, gliding, and sliding, which permit them to navigate both liquid and semi-solid environments [ 5 , 6 , 7 ]. The process of bacterial cells actively moving toward more favorable conditions is known as bacterial taxis.…”

Bacteria-Based Nanoprobes for Cancer Therapy

“…In particular, it is the tumor hypoxic and immunosuppressive microenvironment and its special structure like flagellum and chemotaxis that enable bacteria to target, colonize and proliferate. 20 On the other hand, owing to the intrinsic targeting ability of bacteria, the loaded toxic drugs of bacterial NPs play a therapeutic role with spatial and temporal precision and without systemic effects as much as possible. 21,22 Moreover, it is promising to help ensure biocompatibility of NPs by means of choosing a commensal or probiotic bacterial strain, or live attenuated bacteria or derivatives.…”