Preparation And Study Of STEAP-1 And VEGFR-2 Targeted Ultrasound Contrast Agent

Objective:Through using the prostate cancer Six-transmembrane Epithelial Antigen(STEAP-1)antibody and vascular endothelial growth factor receptor 2(VEGFR-2)as the ligands and biotin-avidin method,a novel targeted ultrasound microbubble contrast agent carrying the above antibodies was prepared to explore its target searching ability and to analyze the enhanced development effect of contrast medium on human prostate cancer nude mice.Valuable early ultrasound diagnostic methods are expected to be obtained.Methods:(1)The human prostate cancer cell line PC3 was cultured and passaged in vitro under sterile environment.PC3 cells were inoculated subcutaneously in male nude mice to establish a male nude tumor-bearing mouse model for human prostate cancer.Ultrasound-enhanced imaging was performed by tail vein injection of targeted ultrasound microbubble contrast agent and ordinary sulfur hexafluoride microbubble contrast agent in tumor-bearing nude mice model.The distribution and the real-time perfusion of contrast agent in nude mice were observed.Using the time-strength curve drawed by the relevant softwares and quantitative analysis to compare peak time(Time to Peak,TTP),peak intensity(Peak Intensity,PI)and mean transit time(Mean Transit Time,MTT)of different contrast agents.(2)The targeted antihypertensive contrast agent was prepared by biotin-avidin method,and STEAP-1 antibody and VEGFR-2 antibody were combined with ordinary sulfur hexafluoride microbubble contrast agent.The microbubble fluorescence was observed under the microscope,and the binding rate and stability were measured by flow cytometry.Results:(1)Targeted ultrasound contrast media carrying STEAP-1 antibody and VEGFR-2 antibody showed positive expression under fluorescence microscopy with green fluorescence using immunofluorescence.(2)The model of human prostate cancer was successfully established.All the groups were significantly enhanced by tail vein injection of ordinary sulfur hexafluoride microbubble contrast agent and two targeted contrast agents,which gradually weakened after reaching a certain peak.Conclusion:(1)Targeted ultrasound contrast agents carrying STEAP-1 antibody and VEGFR-2 antibody can be successfully prepared using the biotin-avidin method and both targeted ultrasound contrast agents are stable;(2)In vitro experiments,targeted ultrasound contrast agent carrying STEAP-1 antibody and VEGFR-2 antibody had better targetability and specificity in tumor-bearing nude mice and VEGFR-2 can specifically bind to neovascular endothelial cells of prostate cancer.This provides a new way to assess neovascularization in prostate cancer.