Impact of vancomycin on the ileum and colon of mice-bearing singeneic mammary carcinoma expressing human HER2

Starting from the evidences of gut microbiota role in tumor development, progression and response to therapy, this project was aimed at evaluating the effect of antibiotic treatment on intestine. The intestinal flora of FVB mice was altered by the oral administration of vancomicyn, mice were then injected with MI6 cells, a singeneic tumor cells line established from spontanueous mammary tumor developped in transgenic d16HER2-transgenic mice [Castagnoli L, 2014]. To analyze the impact of vancomycin on intestinal mucosa, a gene expression profile was performed on colon and ileum samples. FVB female mice were treated with vancomycin starting from four weeks of age until the end of the experiment. Vancomycin was administered in the drinking water at a concentration of 200 mg/L. Mice were sacrificed upon 9 weeks when tumors reached a volume of 150 mm3. For gene expression profile, colon and ileum from NoA and Vancomycin mice were harvested, washed in clean PBS 1x and immediately fronzen in dry ice. Sample were then stored at -80°C until RNA extraction.