THE WAY OF APPLICATION AND DYNAMIC DISTRIBUTION OF CLOSTRIDIUM SPOROGENES AS VECTOR FOR TUMOR GENE THERAPY

Objective To investigate the application and dynamic distribution of Clostridium sporogenes in breast-cancerbearing mice and provide a reference of specific use of Clostridium sporogenes in the treatment of solid tumors.Methods A breast cancer model was created in mice.Endospores and vegetative forms of Clostridium sporogenes were injected into the models through caudal vein and tumor.The mice were selected regularly and killed,the livers,kidneys,spleens and tumors were taken for slice,gram's stain,and observed microscopically.The homogenate of these tissues were collected for anaerobic culture.The bacterial distribution in tissue of different time was observed.Results Vegetative forms of Clostridium sporogenes-like endosporescould survive and breed inside the mionectic environment of breast cancer,with no apparent toxicity.Clostridium sporogenes could massively multiply after intravenous injection,the result was the same as injecting into the tumor,the different from intratumor injection was that a few bacteria could be seen in some organs,they would be cleared soon as the time lapsed.The Clostridium sporogenes were phagocytized by neutrophils that entered the tumor before tumor regression.Conclusion Clostridium sporogenes is a well targeting,high safety and self-limited vector in solid tumor targeted therapy.In the targeted therapy,intravenous injection of either vegetative forms or spores,or both of them,can be applied at will as a vector to play a role inside the tumor.