Tumor-targeting bacteria have been investigated intensively in recent years as
anticancer agents. To ensure the reliability of
infection, bacteria have conventionally been injected intravenously or intraperitoneally into animals or humans. However, systemic
infection of bacteria is rather inconvenient and carries the risk of obvious toxicity. Here we tested whether Salmonella typhimurium
VNP20009, a
tumor-targeting strain, could be administrated orally for
tumor therapy.
Tumor-targeting potential, antitumor effects, as well as toxicity of orally administrated
VNP20009 were investigated in this study. Oral delivery of
VNP20009 not only exhibited high
tumor-targeting potential, but also led to a significant anticancer effect by delaying
tumor growth and prolonging survival in murine
tumor models. As part of combination
therapy, orally administrated bacteria notably improved the antitumor effect of
cyclophosphamide. In vitro and in vivo studies showed that
VNP20009 significantly induced
tumor cell apoptosis. No obvious toxicity was observed during the treatments with oral inoculation of
VNP20009. Comparative analysis of toxicity in
tumor-bearing and
tumor-free mice further revealed that orally administrated Salmonella had high safety compared to conventional systemic
infection of bacteria. The findings indicated that
oral administration of
tumor-targeting bacteria is effective and safe. This approach provides a novel avenue in the application of bacteria as a potential
antitumor agent.