Abstract:

Objective To investigate the uptake of 99Tcm labeled arginine-glutamic-glycine (REG) in human lung cancer cells and the biodistribution characteristics and pharmacokinetics of 99Tcm labeled REG in normal mice. Methods The REG was directly labeled by the 99Tcm and binding tests of 99Tcm and non-small cell lung cancer cells A549 and H1299 were performed. Normal mice were killed at different time points after receiving tail intravenous injections of 99Tcm-REG. Major organs or tissues were excised for determining the percentage of the injected dose per gram of tissue mass (%ID/g). The blood at different time points after mice had received tail intravenous injections of 99Tcm-REG was measured by the gamma counter and parameters of pharmacokinetics were calculated. The tumor %ID/g of H1299 tumor-bearing nude mice and tumor/muscle ratio were measured at different time points. Results The values of radiochemical purity of 99Tcm-REG were (92.90±2.86)%. The binding rates of 99Tcm-REG and A549 cells, and 99Tcm-REG and H1299 cells were (1.29±0.16)% and (2.32±0.31)%, respectively. The biodistribution indicated that 99Tcm-REG in mouse blood was removed rapidly. The radioactivity at 2h after injection was only 20.26% of the radioactivity at 5 min after injection. The radioactivity was mainly concentrated in liver and slowly decreased with time. The radioactivity of kidneys, hearts, and lungs were decreased gradually with time and the levels of radioactivity of other tissues were low. The %ID/g of tumor was 2.02±0.67 and the tumor/muscle ratio was 3.50±1.27 at 2h after injection. Conclusion 99Tcm-REG can be uptaken by human lung cancer cells and may become a potential lung cancer imaging agent.

Key words: peptides, technetium, lung cancer, pharmacokinetics, arginine-glutamic-glycine