Nontyphoidal Salmonella: a potential anticancer agent

Use of bacteria in cancer therapy, despite being considered as a potent strategy, has not really picked up the way other methods of cancer therapies have evolved. However, in recent years, the interest on use of bacteria to kill cancer cells has renewed considerably. The standard and widely followed strategies of cancer treatment often fail either due to the complexity of tumour biology or because of the accompanying side effects. In contrast, these limitations can be easily overcome in a bacteria-mediated approach. Salmonella is a bacterium, which is known for its ability to colonize solid or semisolid tumours more efficiently than any other bacteria. Among more than 2500 serovars of Salmonella, S. Typhimurium has been widely studied for its antagonistic effects on cancer cells. Here in, we review the current status of the preclinical and the clinical studies with a focus on the mechanisms that attribute the anticancer properties to nontyphoidal Salmonella.     

Engineering of Escherichia coli for targeted delivery of transgenes to HER2/neu-positive tumor cells

Targeting of non‐phagocytic tumor cells and prompt release of gene cargos upon entry into tumors are two limiting steps in the bacterial gene delivery path. To tackle these problems, the non‐pathogenic Escherichia coli strain BL21(DE3) was engineered to display the anti‐HER2/neu affibody on the surface. After co‐incubation with tumor cells for 3 h, the anti‐HER2/neu affibody‐presenting E. coli strain was selectively internalized into HER2/neu‐positive SKBR‐3 cells. The invasion efficiency reached as high as 30%. Furthermore, the bacteria were equipped with the phage ϕX174 lysin gene E‐mediated autolysis system. Carrying the transgene (e.g., eukaryotic green fluorescent protein, GFP), the tumor‐targeting bacteria were subjected to the thermal shock to trigger the autolysis system upon entry into HER2/neu‐positive cells. Flow cytometric analysis revealed that 3% of infected cells expressed GFP 24 h post thermal induction. Overall, the results show a promise of the proposed approach for developing bacteria as a delivery carrier. Biotechnol. Bioeng. 2011; 108:1662–1672. © 2011 Wiley Periodicals, Inc.