Pseudomonas Aeruginosa Preparations The Role Of Mouse Pancreatic Cancer Xenograft Tumor Experiments

[Objective] We study the tumor inhibition effect of Pseudomonas Aeruginosa (PA-MSHA) treatment on pancreatic cancer xenograft mouse model in vivo. We discussed the possible mechanism of tumor inhibition effect of PA-MSHA. Our research showed that PA-MSHA treatment has great potential in treating pancreatic cancer.[Method] We created the pancreatic cancer xenograft mouse model by injecting 0.2ml (2.5×107/ml)mouse pancreatic cancer (MPC) cells into the subcutaneous tissue of the mouse's right axillary fossa.40 tumor bearing mice were successfully established at day 6 post-injection with a tumor size of 5mm x 5mm and these mice were randomly divided into 4 different groups with different abdominal injection treatments by every other day for 7 times. These groupings were 0.9% NS group (injected with 0.2ml 0.9% NS),5-FU group (injected with 0.2 mg 5-FU), PA-MSHA group (injected with 0.2 ml PA-MSHA) and PA-MSHA+ 5-FU group (injected with 0.2 ml PA-MSHA and 0.2 mg 5-FU). The tumor size and weight were measured on each injection occasion for these mice. At day 20, all the mice were sacrificed and their tumors were extracted for multiple molecular assays. First, the final measurement of their weight and size were determined. Second, tumor biopsies were performed using HE staining and p53 protein expression was detected by immune-histochemical staining. Finally, flow cytometry method was used to determine the cell cycle stages of these tumors cells. In addition, proliferate blood was removed from the mouse eye vein to perform white blood cell (WBC) counts.[Results] We have successfully developed the pancreatic cancer xenograft mouse model for this study. The tumor size and weight for the PA-MSHA and PA-MSHA+5-FU groups were significantly reduced (p <0.05), the rate of tumor inhibition at 18.84% and 45.18% respectively, when compared to the control group. Flow cytometry showed that the PA-MSHA and PA-MSHA+5FU groups were predominately at G0/G1 cell cycle phase. Immuno histochemical assay showed that p53 protein expression for PA-MSHA and PA-MSHA+5FU groups were significantly lower (p<0.05), at 43.25±2.62% and 41.6±4.56% respectively, when compared to the control group. Finally, the WBC counts for these 2 groups were observed to be significantly increased.[Conclusion] Our study shows that PA-MSHA, and in combination with 5-FU, treatments can reduce tumor size and weight and therefore have inhibition effect in tumor growth. We also observed that the WBC counts in the PA-MSHA and PA-MSHA+5-FU groups were increased compare to 5-FU group, which indicated the restoration of immunity for these animals. PA-MSHA can reduce the expression of p53 protein, which might be a trigger for tumor cell apoptosis. PA-MSHA could enhance the inhibition effect of 5-FU treatment. Therefore, we postulate that the PA-MSHA, and its combination with 5-FU treatment has potential in treating pancreas cancer.