【作者】 洪智慧；

【导师】 刘增礼；

【作者基本信息】 苏州大学 ， 影像医学与核医学， 2011， 硕士

【摘要】 研究目的:研究（131）^I标记抗胃泌素释放肽前体( Pro-gastrin-releasing peptide（31-98）, ProGRP_（31-98）)单链抗体scFv在正常昆明小鼠及荷小细胞肺癌裸鼠的体内分布规律,并对荷小细胞肺癌裸鼠进行初步显像,探讨（131）^I-anti-ProGRP_（31-98） scFv作为特定肿瘤显像剂的可能性。研究方法:1.利用流式细胞仪和免疫组化两种方法分别检测小细胞肺癌NCI-H446、宫颈癌Hela、大细胞肺癌H460和肺腺癌A549细胞株及其组织中的ProGRP表达情况。2.采用氯胺-T法标记制备（131）^I-anti-ProGRP_（31-98） scFv;凝胶柱分离法分离纯化标记产物;纸层析法测定标记产物的标记率、放化纯;将（131）^I-anti-ProGRP_（31-98）scFv分别置于37℃水浴箱及与正常人血清混合后在不同时间点测定放化纯以了解其稳定性;通过细胞结合分析法测定标记产物的免疫活性。3.自正常昆明小鼠尾静脉注射（131）^I-anti-ProGRP_（31-98） scFv后,于不同时间点剪断颈动脉处死小鼠,取血液及各主要脏器组织标本,计算每克组织注射百分剂量率（%ID/g）。利用NCI-H446细胞建立人小细胞肺癌荷瘤裸鼠模型,自尾静脉注射（131）^I-anti-ProGRP_（31-98） scFv后,于不同时间点处死裸鼠并取血液、移植瘤及各主要脏器组织标本,计算不同时间点各脏器组织的%ID/g和瘤体/非瘤体组织放射性计数比值（T/NT值）。4.对小细胞肺癌荷瘤裸鼠模型进行（131）^I-anti-ProGRP_（31-98） scFv初步显像,观察移植瘤的大体显像情况,利用ROI技术在显像图上勾画移植瘤轮廓并计算瘤体与对侧相同部位的T/B值。研究结果:1.流式细胞仪检测显示NCI-H446、Hela、H460及A549细胞株ProGRP的表达率分别为95%、77%、53%和4%。免疫组化检测结果显示,小细胞肺癌、宫颈癌及大细胞肺癌组织切片的细胞胞浆内均有二氨基联苯胺（DAB）染色阳性颗粒分布,而肺腺癌组织切片中未见明显染色阳性细胞。2. （131）^I-anti-ProGRP_（31-98） scFv标记率为93.35±0.67%,标记产物纯化后即刻放化纯为98.49±1.21%;在37℃水浴箱中放置24 h后放化纯为94.30±0.41%,48 h后测定仍大于90%,与正常人血清充分混合在37℃水浴箱中放置24 h后放化纯为83.61±2.19%,48 h测定大于80%;（131）^I-anti-ProGRP_（31-98） scFv对NCI-H446和A549细胞株的免疫结合率分别为85.36%、21.02%。3. （131）^I-anti-ProGRP_（31-98） scFv在正常昆明小鼠和小细胞肺癌荷瘤裸鼠体内主要通过肝脏、肾脏代谢,血液及各主要脏器组织的清除速度快,脑组织和肌肉组织摄取不明显,符合单链抗体在机体内的一般代谢分布规律。注射12 h后移植瘤体的%ID/g高于其他脏器及组织,24 h达到最高为5.38±0.92%。T/NT值随时间的延长逐渐升高,至注射后24 h基本达到最高。4.注射（131）^I-anti-ProGRP_（31-98） scFv 1 h后,小细胞肺癌移植瘤部位出现放射性浓聚,随时间延长移植瘤部位的放射性浓聚程度逐渐增强,至24 h最为清晰。结论:1. （131）^I-anti-ProGRP_（31-98） scFv标记简便,标记率及放化纯高,体内外稳定性好,主要通过肝肾代谢,血液及各主要脏器廓清速度较快。2. （131）^I-anti-ProGRP_（31-98） scFv在小细胞肺癌荷瘤裸鼠体内的分布结果表明,它可在移植瘤组织内积聚,瘤体与主要器官的T/NT值随时间延长而上升,至24 h到达最高值。3. （131）^I-anti-ProGRP_（31-98） scFv有望成为一种新型的小细胞肺癌放射免疫显像剂,值得进一步深入的研究。更多还原

【Abstract】 Objective:To evaluate the biodistribution of （131）^I labeled anti-ProGRP_（31-98） scFv in healthy Kunming mice, tumor-bearing mice and primarily perform the imaging in nude mice bearing human small cell lung cancer so as to investigate the feasibility of （131）^I- anti- ProGRP_（31-98） scFv as a new tumor tracer for diagnosing of certain tumors.Methods:1. The ProGRP expression in NCI-H446, Hela, H460 and A549 cell lines was detected respectively by flow cytometry and its expression in these tumor tissues was estimated by immunohistochemistry.2. Chloramine-T method was used for （131）^I labeling anti-ProGRP_（31-98） scFv; （131）^I-anti-ProGRP_（31-98） scFv was purified by gel column separation method; Labeling efficiency and radiochemical purity were measured by paper chromatography; （131）^I-anti-ProGRP_（31-98） scFv was incubated with healthy serum at 37℃, and radiochemical purity was measured at different time to determine the stability of labeled product; Immunocompetence of labeled product was determined with cell conjugation assay. 3. Biodistribution study was performed following an i.v.injection （given via the tailvein） of （131）^I-anti-ProGRP_（31-98） scFv. Healthy Kunming mice were sacrificed by cutting off carotid artery at designated time points in group, and the blood and major organs were removed, weighed, and counted in a gamma scintillation counter to determine the %ID/g （percentage of injected dose related to the organ weight） for each radioactive substance. In the same way, major organs and transplanted tumor tissues of nude mice bearing human small cell lung cancer were sampled for calculating %ID/g and tumor/non-tumor （T/NT） ratios.4. After injection of （131）^I-anti-ProGRP_（31-98） scFv, continuous images of the nude mice bearing SCLC were initially carried out at different time, and then tumor/base（T/B）ratios were calculated.Results:1. The expression rates of ProGRP in NCI-H446, Hela, H460, A549 cell lines were 95%, 77%, 53% and 4% respectively. The results of immunohistochemistry showed that positive granules （DAB staining） were distributed in intracytoplasm of small cell lung cancer, cervical cancer and large cell lung cancer, no obvious staining cells were found in lung adenocarcinoma.2. The labeling rate of （131）^I-anti-ProGRP_（31-98） scFv was 93.35±0.67%, and the radiochemical purity was 98.49±1.21%. After incubation at 37οC for 24 h, the radiochemical purity was 94.30±0.41%, and still maintained above 90% at 48 h. Meanwhile, after incubation with healthy human serum for 24 h, the radiochemical purity was 83.61±2.19%, and still maintained above 80% at 48 h. The immunobinding rates of NCI-H446 cell and A549 cell were 85.36% and 21.02%.3. The vivo distribution of （131）^I-anti-ProGRP_（31-98） scFv in the normal Kunming mice and nude mice bearing human small cell lung cancer showed that the metabolism of （131）^I-anti-ProGRP_（31-98） scFv mainly depended on liver and kidney with rapid elimination in blood and other main organs, the brain and muscle did not uptake much, and it was consistent with general scFv. The %ID/g of tumor was obviously higher than that of other organs at 12 h and arrived at top 5.38±0.92% at 24 h post-injection. The T/NT ratio increased gradually and arrived at top at 24 h.4. The tumor of nude mice bearing SCLC was visualized at 1 h after injection of （131）^I-anti-ProGRP_（31-98） scFv, The radioactivity in tumor site accumulated gradually and the tumor image became the clearest at 24 h post-injection.Conclusions:1. Labeling of （131）^I-anti-ProGRP_（31-98） scFv is easy, it not only has high labeling efficiency and radiochemical purity, but also has good stability in vitro and in vivo. （131）^I-anti-ProGRP_（31-98） scFv was metabolized mainly in kidney and liver, the blood and other major organs radioactivity of （131）^I-anti-ProGRP_（31-98） scFv decreased rapidly. 2. The biodistribution in SCLC tumor-bearing mice showed that （131）^I-anti-ProGRP_（31-98） scFv can be accumulated in tumor, the ratios of T/NT increased as time prolongs and arrived at top at 24 h.3. （131）^I-anti-ProGRP_（31-98） scFv has the potential to become radioimmunoimaging agent of SCLC. It deserves further study.更多还原