Research on anti-tumor mechanism of attenuated Salmonella typhimurium VNP20009 / 药学学报

Attenuated Salmonella typhimurium VNP20009 is a widely used natural oncolytic bacterium, which has great application potential given its unique characteristics, including clinical safety, tumor targeting specificity, and explicit genome sequence. Here, we show that tumor progression can be effectively reduced by intraperitoneal administration with VNP20009 in a mouse model of melanoma (all animal experiments were conducted in accordance with the Animal Ethics Committee of China Pharmaceutical University); co-culture experiment in vitro demonstrated that VNP20009 can induce the polarization of macrophage M1, accompanied by expression of inflammation-related factors; flow cytometry analysis showed that VNP20009 induced the increase of immune cell infiltration in tumor. Further analysis showed that T cells infiltration in tumor-draining lymph node (TDLN) increased, and VNP20009 induced the activation of CD4+ T cells and CD8+ T cells in tumor. Our results demonstrate that VNP20009 treatment significantly inhibited melanoma tumors by remodeling tumor-associated macrophages to an M1-like phenotype, as well as recruiting and activating cytotoxic T cells, combined with its own antigenic activity to exert anti-tumor immunity.

Effects of temperature, pH, and H2O2 on the growth and biofilm formation of attenuated Salmonella VNP20009 / 药学学报

Attenuated Salmonella VNP20009 specifically colonizes and proliferates within tumor tissues and inhibits tumor growth. It has been used as drug delivery vehicle or in combination with other therapies (such as chemotherapy), which shows a good application potential in tumor therapy. In this paper, study was conducted to determine the physiological changes of growth curve and formation of bacterial biofilm of VNP20009 under various environmental stresses, such as temperature, pH, and H2O2. The results showed that VNP20009 could grow normally under the conditions of 42 ℃, pH 6.5, and 1 mmol·L-1 H2O2. Furthermore, the weak acid environment was beneficial to the biofilm formation of VNP20009. This study provides a basis for in-depth study of the survival mechanism and application of attenuated Salmonella.