^(99m)Tc-depreotide与人肺腺癌A549细胞生长抑素受体结合实验

Observation on ^(99m)Tc-depreotide with somatostatin receptor of pulmonary adenocarcinoma A549 cells

目的:通过99mTc-depreotide与人肺腺癌A549细胞结合的体外实验,评价99mTc-depreotide作为肿瘤生长抑素受体显像剂的可能性。方法:采用受体放射分析法,分别在4、25和37℃条件下观察温度对A549细胞摄取99mTc-depreotide的影响。在4和37℃条件下培养A549细胞,并于不同时间点计算99mTc-depreotide在A549细胞内的滞留率,同时计算半清除时间。将A549细胞与99mTc-depreotide在37℃条件下分别孵育不同时间,分析肿瘤细胞对99mTc-depreotide的内化率和细胞膜表面结合率的变化。结果:在相同时间点,摄取率随温度升高逐渐增加,证明其摄取存在温度依赖性;在37℃条件下,摄取峰时为60min。A549细胞对99mTc-depreotide的清除速度不依赖于温度,37℃条件下的半清除时间为48 min。37℃条件下,99mTc-depreotide在A549细胞内发生特异性内化,内化活性随时间延长而逐渐增加。结论:A549细胞能够特异性结合99mTc-depreotide,在37℃条件下表现出适于受体显像的摄取峰值时间和半清除时间。

Objective：Observation on 99mTc-depreotide with somatostatin receptor of human pulmonary adenocarcinoma A549 cells in vitro in order to evaluate the potentiality of 99mTc-depreotide as a somatostatin receptor imaging agent.Methods：Using receptor radioligand binding assay,this work observed the effect of temperature on the uptake of 99mTc-depreotide by A549 cells at 4,25,and 37 ℃.A549 cells were cultured at 4 and 37 ℃ and stagnation ratio of 99mTc-depreotide in A549 cells and the half clearance time were calculated at different time points.A549 cells were incubated with 99mTc-depreotide at 37 ℃ for various times.The changes in the internalization and surface-bound activity of 99mTc-depreotide with A549 cells were analyzed.Results：The uptake index increased with the increasing temperatures at the same time point,demonstrating that the uptake was temperature-dependent.The peak time for maximum uptake was 60 min at 37℃.The cleaning speed of 99mTc-depreotide by A549 cells did not depend on temperature,and the half cleaning time was 48 min at 37℃.At 37℃,99mTc-depreotide had specific internalization in A549 cells,and the internalization activity gradually increased when the time was prolonged.Conclusion：A549 cells have specific binding with 99mTc-depreotide,and exhibits peak time of maximum uptake and half cleaning time for receptor imaging at 37℃.