TY - JOUR T1 - <strong>Radiolabeing of Tyr-</strong><strong>cNGQGEQc with </strong><strong>iodine-131</strong><strong> and its biodistribution and </strong><strong>radioherapy in nude mice bearing lung adenocarcinoma</strong> JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1266 LP - 1266 VL - 56 IS - supplement 3 AU - Li Gui Ping Y1 - 2015/05/01 UR - http://jnm.snmjournals.org/content/56/supplement_3/1266.abstract N2 - 1266 Objectives Based on the polypeptide cNGQGEQc for specifically binding with pulmonary adenocarcinoma found previously, cNGQGEQc was radiolabelled with 131I. Then the radioactive distribution and the inhibitory effect of 131I-Tyr-cNGQGEQc in nude mice bearing lung adenocarcinoma were observed.Methods The coupling of cNGQGEQc and tyrosine was done in the processing of solid phase synthesis of polypeptide. Chloramine-T was used for radiolabelling of cNGQGEQc with 131I. Labeling efficiency and radiochemical purity of 131I-Tyr-cNGQGEQc were determined by paper chromatography. Stability was determined in saline and human serum incubating in water bath at 37℃ for 24h, respectively. The octanol-water partition coefficient lg P was calculated. The biodistribution of 131I-Tyr-cNGQGEQc in nude mice bearing NCI-H1975 was determined at 3h post-injection. The radiotherapy effect of 131I-Tyr-cNGQGEQc to transplantation tumor in nude mice was conducted.Results The labeling efficiencies of 131I-Tyr-cNGQGEQc were greater than 90% with the radiochemical purity (RCP) of more than 95%. The RCP became to (93.12±1.18) % and (88.34±5.43)% incubated with saline and healthy serum for 24h in 37℃. The octanol-water partition coefficients (lg P) was -1.75, suggesting that labeled polypeptides was hydrosoluble. The radioactive in kidney of 131I-Tyr-cNGQGEQc was obviously higher than those of other organs at 3h after intravenous injection; the %ID/g in kidney was 11.32, while in tumor 2.62. 131I-Tyr-cNGQGEQc had obvious inhibitory effect for transplantation tumor in nude mice bearing NCI-H1975 lung adenocarcinoma. After treatment of 30 days the tumor inhibitory rates was obvious higer than control group of 131I.Conclusions Preparation of 131I-Tyr-cNGQGEQc is not only simple, but also has high labeling efficiency. 131I-Tyr-cNGQGEQc has good stability in vitro and in vivo and a good affinity and effective inhibit effect for the NCI-H1975 lung adenocarcinoma.Research Support This research was supported by Natural Science Foundation of Guangdong Province, China (S2013010014420), Science and Technology Planning Project of Guangdong Province, China (2012B031800391) and Nanfang Hospital Dean Fund Project (2012Z008) ER -