Multi-modal Evaluation Of Inhibitory Effect Of Bradykinin B1Receptor Antagonist R-954on Cultured Breast Cancer Cells

Objective: The study is to investigate the inhibitory effect of high-selectivebradykinin receptor subtype B1inhibitor, R-954on the growth of breast tumor xenograftsin mice by multi-modal evaluation including measuring the tumor volume and weight, MRimaging, immunohistochemical staining, and RT-PCR (reverse transcription polymerasechain reaction).Methods: Mouse xenograft model of breast cancer is constructed by subcutaneousinoculation of4T1breast cancer cells. Mice are randomly divided into two groups afterforming tumor, R-954is injected subcutaneously in the experimental group (dosinginjection2mg/kg), while PBS buffer is injected subcutaneously in the control group (thesame dose). After15days continuous subcutaneous injection of R-954, the tumor weight,volume and the growth curve are observed. Tumor vascular endothelial growth factor(VEGF) and anti-CD34antibody expression are detected by immunohistochemical stainingand RT-PCR. The tumor maximum cross-sectional area is observed by MR imaging.Evaluation of the inhibitory effect of bradykinin receptor B1subtype, R-954on breastcancer tissue and analysis of tumor vessels and the expression of related factors bymorphology, pathology, imaging and immunology detection. Using statistical methods, allexperimental data are detected and analyzed.Results: The tumor volume is smaller in treatment group than that in control group[(468.43294.987) mm3vs.(843.349165.240) mm3, P <0.05]. The tumor weight issignificantly lighter in treatment group than that in control group [(0.8090.149) g vs.(1.4660.225) g, P <0.01]. Furthermore, the relative tumor volume of each group in miceis calculated and the corresponding tumor growth curve is drawn. The relative tumorgrowth curve shows an increasing growth in control group while relatively flat in treatmentgroup. By MR imaging sequences, the tumor maximum cross-sectional area is observed inboth groups with significant difference (P <0.01). Anti-CD34antibody is expressed in twogroups based on immunohistochemical observation. Semi-quantitative analysis shows that tumor micro-vessel density (MVD) detected by anti-CD34antibody in the treatment groupis significantly lower than that in the control group, which is observed in both groups withsignificant difference (P<0.01). RT-PCR results show that VEGF mRNA expression levelsin the treatment group is lower than that in the control group (P <0.01).Conclusion: High-selective bradykinin receptor subtype B1, R-954can notablyinhibit the growth of breast tumor xenografts in mice effectively, and the inhibitory effectcan be evaluated by multi-modal observation including measuring the tumor volume andweight, MR imaging, immunohistochemistry and RT-PCR methods. The inhibition ofR-954on the tumor may be accomplished by the inhibition of angiogenesis.