Efficacy of a genetically-modified Salmonella typhimurium in an orthotopic human pancreatic cancer in nude mice.

We report here a tumor-targeting strategy for pancreatic cancer using a modified auxotrophic strain of Salmonella typhimurium. The genetically-modified strain of S. typhimurium requires the amino acids arginine and leucine. These mutations preclude growth in normal tissue but do not reduce bacterial virulence in tumor cells. The tumor-targeting strain of S. typhimurium, termed A1-R and expressing green fluorescent protein (GFP), was administered to an orthotopic human pancreatic tumor expressing red fluorescent protein (RFP) in nude mice. After 7 days of treatment, the pancreatic cancer had regressed without the need of chemotherapy or any other treatment. This new strategy demonstrates the clinical potential of bacterial targeting for pancreatic cancer.