Science

Salmonella strain shows antitumor activity in animal model

Last Updated: 2008-03-06 13:48:24 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Injections of Salmonella choleraesuis slow tumor growth and prolong survival in a murine model of orthotopic hepatocellular carcinoma, Taiwanese researchers report in the February 15 issue of the International Journal of Cancer.

Dr. Che-Hsin Lee and colleagues at National Cheng Kung University Medical College in Tainan note that in previous research they demonstrated that an attenuated vaccine strain of S. choleraesuis targets tumors and is oncolytic in subcutaneous tumors. However, this "may not necessarily indicate efficacy against orthotopic tumors," they explain.

To explore further, the team administered S. choleraesuis systemically to mice bearing both subcutaneous and orthotopic hepatocellular carcinoma tumors. The bacteria rapidly accumulated within the tumors, with tumor-to-normal tissue ratios exceeding 1,000-10,000 to 1, for at least 30 days.

Compared with controls with untreated tumors, S. choleraesuis "significantly prolonged the animal survival, reduced the tumor size, as well as upregulated interferon (IFN)-gamma," Dr. Lee and associates report. This in turn stimulated production of the IFN-inducible chemokines.

Immunohistochemical staining of the tumors showed decreased microvessel density, increased infiltration of neutrophils, the presence of CD4 and CD8 T-cells, and induced cell death in the tumor microenvironment.

Dr. Lee's team writes: "These results suggest that tumor-targeted therapy using S. choleraesuis, which exerts tumoricidal and antiangiogenic activities, represents a potential strategy for the treatment of hepatocellular carcinoma."

Int J Cancer 2008;122:930-935.