Cancer Theranostics With Nano Enabled Bacterial Bots

Abstract

The contemporary cancer therapeutics are being strategically designed to obtain improved outcomes as compared to the conventional methods. The primary challenges faced by the conventional mode of therapies such as surgeries, radiation therapies, and later chemotherapy are difficulty in tumor accessibility, undesirable impact on normal cells, ineffectiveness towards cancer stem cells, missing the targets, rapid drug release prior to reaching the targets, poor pharmacokinetics of drugs, and resistance development to the therapy. In order to focus on the improvements, target specificity through small molecules, aptamers, antibodies, nucleic acid, stimuli sensitive polymers have been developed. Coating of the drug with polymers and loading the drugs on nano-carriers for enhanced bioavailability, slower release and safety from immune attacks have also been introduced. Developing methods for immunotherapy are also being practiced. Gradually the newer methods such as gene therapy, immunotherapy, and combined therapies have overtaken the conventional methods. Although these methods have shown improved results in comparison to the previous methods but the threat imposed by the cancer stem cells and drug resistance are still continuing. The advent of bacteria-mediated therapy has shown some light towards a path of developing a resistance free cancer therapy. Since, the anaerobic bacteria preferably colonize in the hypoxic areas of the tumor and act on the core of the tumor, hence, there is a better opportunity for the bacteria to eradicate the stem cells and prevent relapse of cancer. The attenuated strains achieved through genetic engineering and over-expression of endotoxins and therapeutic genes have generated hopes for a better future of cancer therapeutics. The commonly used strains are Salmonella, Bifidobacterium, Clostridium, E. coli and Lactic acid bacteria (LAB). The bacteria-based therapy can have two usages, first as a therapeutic entity and second as a delivery vehicle. The anti-cancer effects of the bacteria