The aim of this study was to evaluate the efficacy of Salmonella typhimurium A1-R (A1-R) on breast cancer brain metastases. High brain-metastatic variants of murine 4T1 breast cancer cells expressing red fluorescent protein (RFP) were injected into the left ventricle of transgenic nude mice expressing nestin-driven green fluorescent protein (ND-GFP). ND-GFP mice express GFP in nascent blood vessels. At various time points, the tumors and vasculature in the brain were imaged by laser-scanning confocal and stereo fluorescence microscopy. Eighty percent of the cells that reached the brain extravasated and grew perivascularly; twenty percent of the cells, however, proliferated within the vasculature which may lead to thrombosis-like infarction of the brain parenchyma. Compared to the control group, mice treated with Salmonella typhimurium A1-R (A1-R) had significant inhibition of brain metastasis and increased survival (p<0.05). The results of the present study suggest the clinical potential of bacterial therapy of breast cancer brain metastasis.

Citation Format: Yong Zhang, Shinji Miwa, Nan Zhang, Robert M. Hoffman, Ming Zhao. Efficacy of Salmonella typhimurium A1-R on experimental breast cancer brain metastasis. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 709. doi:10.1158/1538-7445.AM2014-709