Experimental study of TNFR imaging in tumor

Investigate the feasibility of ^99mTc-TP1093 as a molecular imaging agent targeting TNF receptor-positive tumor. Results show that: 1. The labeling rate of ^99mTc-TP1093 was (97.18 ± 0.90)%, the radiochemical purity of ^99mTc-TP1093 was (93.34 ± 0.91)% after placeing at room temperature for 4 h, and the oil-water distribution coefficient lgP was -(1.68 ± 0.09); 2. The labeled peptide dynamics was fited for two-compartment model with a weighting coefficient l/c in health rabbits, the t_1/2α and t_1/2β were (2.68 ± 0.54) min and (69.15 ± 20.34) min respectively; 3. The radioactivity was eliminated rapidly from blood and excreted mainly through urinary system post intravenous injection of ^99mTc-TP1093 in normal mice and rabbits, stomach and thyroid cannot be shown during imaging process in health rabbits; 4. The radioactivity can be quickly uptaken by tumor-burden U937 nude mice after intravenous injection of ^99mTc-TP1093, the tumor image is clear at 0.5 h with a T/NT ratio 5.14. Competitive imaging using 300 times of non-labeling TP1093, the tumor image was obviously weakened at 0.5 h with a T/NT ratio 2.52. This study indicates that ^99mTc-TP1093 can be easily prepared with a high labeling rate, had a favourable stability in vitro and dynamics characteristics in animals, was uptaken selectivity by tumor mediating through TNFR, and then was a potential molecular imaging agent targeting TNF receptor. (authors)