Preparation Of Radionuclide Labeled Peptides RET And REG And The Experimental Study On Molecular Imaging In Nude Mice Bearing Human Lung Cancer

Objective To investigate the biodistribution characteristics and pharmacokinetics in nomal mice and uptake in human lung cancer cells of 99Tcm labeled arginine-glutamic-glycine (REG) and 99Tcm labeled arginine-glutamic-glutamic (RET). Methods REG and RET was labeled directly with 99Tcm. The biodistribution of 99Tcm-REG and 99Tcm-RET were studied at 2 min,5 min,10 min,30 min,1 h,2 h,4 h,8 h, and 24h, respectively, after intravenous injection in normal mice. At different time points, the mice were sacrificed and organs of interest were excised, weighted and counted by a gamma counter. The organ uptake was calculated as a %ID/g. The scintigraphy of 99Tcm-REG was performed at 0.5,1,2,4.5,5,6h after intravenous injection. Results The radiochemical purity of 99Tcm-REG were more than 90%, and the specific binding efficiency of 99Tcm-REG with A549 and H1299 cells was (1.29±0.16)% and (2.32±0.31)%. The %ID/g of tumor was 1.95±0.73 at 1h after injection. The tumor in nude mice could be best imaged at 2-6h after intravenous injection of 99Tcm-REG.In the first 24h after injection, the biodistribution in mice showed rapid blood excretion and most of the radioactivity was observed in liver. The radiochemical purity of 99Tcm-RET were more than 90%, and the specific binding efficiency of 99Tcm-RET with H1299 cells was (3.56±0.37)%. The largest uptake ratio of tumor to non-tumor (heart and blood) was 5.7±0.21 and 12.4±0.11 at 4h after injection. The tumor in nude mice could be best imaged at 4～6h after intravenous injection of 99Tcm-RET. The radiochemical purity of 99Tcm-RET and 99Tcm-REG were (93.15±2.02)% and (92.90±2.86)%. The binding efficiency of 99Tcm-RET with H1299 cells were (3.56±0.37)% and (2.32±0.31)%., The uptake of tumor was (4.96±1.05)%ID/g at 4 h after injection, and tumor in nude mice could be best imaged at 4.5-6h after intravenous injection of 99Tcm-RET. The %ID/g of tumor was 1.95±0.73 at 2h after injection 99Tcm-REG, and tumor could be imaged at 2～6h after intravenous injection.Conclusion 99Tcm-REG and 99Tcm-RET can be uptaked in human lung cancer cells,and might possibly become a potential lung cancer imaging agent.