Bacteria as a therapeutic approach in cancer therapy

Abstract

In the wake of growing global burden of cancer, newer cancer prevention and control modalities are being explored. One such novel experimental strategy is the implication of natural and genetically modified non-pathogenic bacterial species as potential antitumor agents. This therapy is based on the fact that live, attenuated or genetically modified non-pathogenic bacterial species are capable of multiplying selectively in tumours and inhibiting their growth. Moreover due to their selectivity for tumour tissues, these bacteria and their spores also serve as ideal vectors for delivering therapeutic proteins to tumours. Bacterial toxins too have been explored for their anti-cancer potential. Although the oncolytic potential of bacteria was recognized several hundred years back yet the bacterial therapy failed to establish because of certain drawbacks associated with it like toxicity, lack of specificity and inconvenient administration of bacteria. However the emergence of gene therapy and recombinant DNA technology has revived the interest in bacterial therapy and a variety of applications employing bacteria have been investigated. Out of these, the most potential and promising strategies are bacteria based gene-directed enzyme prodrug therapy, anaerobic bacteria vector-mediated cancer therapy and immunotherapy. These therapies have demonstrated significant efficacy in preclinical studies and some are currently under clinical investigation.