ABSTRACT
Cancer remains one of the leading causes of morbidity and mortality worldwide. The treatment of cancer without any toxicity and severe side effects to normal cells is a million dollar question at present. Conventional chemotherapeutic agents used for cancer therapy have not only nonspecific toxicity toward normal body cells but also develop resistance to chemotherapy in due course of treatment. This dilemma gave rise to an immediate necessity to search for nontoxic anticancer agents from new unexploited or less exploited natural sources. From this point of view, nonpathogenic bacterial species are being explored as potential antitumor agents, either to provide direct tumoricidal effects or to deliver tumoricidal molecules. In this chapter we aim to discuss the potentiality of bacteria and their bioactive proteins/peptides as ideal anticancer agents against different types of tumors. Salmonella typhimurium (S. typhimurium) has been thoroughly researched in the last three decades and have been proved to be a successful bacterial vector for cytotoxic moieties, apoptotic inducers, prodrug enzymes, cytokines, chemokines, tumor-associated antigens, and DNA and RNA antisense or vaccine fragments. Furthermore, genetically modified and attenuated bacteria have been designed as direct anticancer agents. Bacterial toxins and spores have also emerged as promising anticancer agents. Some of the bacteriocins such as nisin, plantaricin A, Colicin, Microcin, Pediocin, Pyocin, Bovicin, and Smegmatocin have shown selective cytotoxicity toward various tumors as compared to normal cells, making them promising candidates for further investigation and clinical trials. The broad-spectrum anticancer properties of bacteria and their bioactive proteinaceous components have enlightened a new hope toward creating a new era of effective cancer therapy in the future.
