Salmonella-1, tumors-0

A group led by researchers at Chonnam National University has shown that a non-virulent strain of Salmonella typhimurium expressing an immune-stimulating protein from another bacterial species shrank tumors, providing a bacteria-based immunotherapy that could potentially treat cancer in a single dose.

Salmonella and other anaerobic bacteria are attractive agents for delivering cancer therapies because the microbes target the hypoxic tumor microenvironment. In 2002, now-defunct Vion Pharmaceuticals Inc. demonstrated limited efficacy of VNP20009, an intratumorally injected, attenuated S. typhimurium strain, in Phase I cancer trials. In preclinical studies, attenuated Salmonella strains have been used to deliver cytokines to tumors, and last year, a University of California San Diego group used attenuated Salmonella to deliver pulses of therapeutic proteins to tumor tissues (see “Bacteria with a Pulse.” BioCentury Innovations (Sept. 1, 2016))...