Abstract
1794
Objectives: To investigate the possibility of using CXCR4 siRNA labeled with 99mTc for the breast cancer CXCR4 gene imaging in nude mice.
Methods: (1)The siRNAs targeting CXCR4 mRNA and control siRNA were designed using BLAST software.The best siRNA sequences was screened by qRT-PCR or westetrn blotting.The synthesis of radionuclide probe with HYNIC as chelating agent and SnCl2 as reducing agent.(2)30 nude mice were divided into 6 groups(5/group).Three groups of mice were implanted with control cell line T-47D,the other were implanted with T-47D-CXCR4.The nude mice impalnted diffrent cell lines were injected with 99mTcO4-,99mTc-HYNIC-control-siRNA and 99mTc-HYNIC-siRNA1026,respectively. After injection of the probe, the above six groups of nude mice were visualized at 1h, 4h and 10h respectively.Then we calculated the radioactivity count ratio between tumor and contralateral limb(T/M ratio).The measured data were analyzed by one-way ANOVA.
Results: The labeling rate and the radiochemical purity of molecular probe was (62.71±3.26)% and more than 95%,respectively.The 99mTc-HYNIC-siRNA had stable chemical properties and bond to the target gene sequence.The probe gathered in tumor for a long time.At 10 hours after the injection of the probe, the concentration of radionuclides is obvious in the tumor tissue.
Conclusions: With the bifunctional chelator HYNIC and SnCl2,the CXCR4 siRNA molecules probe that labeled with 99mTc was constructed successfully. The molecular probe has the better labeling efficiency, stability and interference activity.The 99mTc-HYNIC -siRNA1026 could specificity accumulated in the tissue with CXCR4overexpression Key words:CXCR4; siRNA; T-47D cells; 99mTc
