生长抑素受体2型嵌合基因转移的无创监测

Noninvasive monitoring of somatostatin receptor type 2 chimeric gene transfer.

作者信息

Kundra Vikas, Mannting Finn, Jones Alun G, Kassis Amin I

机构信息

Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.

出版信息

J Nucl Med. 2002 Mar;43(3):406-12.

PMID:11884502

Abstract

UNLABELLED

Noninvasive monitoring of gene transfer will benefit basic research and patient care. Most gene-transfer imaging systems do not directly detect the gene of interest, and most do not exploit radiopharmaceuticals that have Food and Drug Administration approval for total-body use. (111)In-Octreotide is used clinically to locate tumors overexpressing primarily somatostatin receptor type 2 (SSTR2). We report the in vitro and in vivo detection of SSTR2 chimeric gene transfer with this radiopharmaceutical.

METHODS

Full-length SSTR2A was ligated into a vector downstream of a 5' Igkappa leader sequence and the hemagglutinin A (HA) sequence. The vector plus insert was then introduced into HT1080 cells. Igkappa and HA domain functions were confirmed by immunologic methods. Receptor binding was studied in transfected cells incubated with (111)In-octreotide with and without somatostatin-28. Mice bearing tumors produced by transfected cells were injected with (111)In-octreotide for biodistribution and imaging studies.

RESULTS

Cell-membrane localization by the amino-terminal Igkappa domain was confirmed by immunofluorescence. The HA domain was identified by enzyme-linked immunosorbent assay, immunofluorescence, and Western blotting analysis with anti-HA antibodies. (111)In-Octreotide detected the SSTR2 portion of the fusion protein in vitro (receptor-binding assay) and in vivo (biodistribution studies and gamma-camera imaging). In addition, in vitro studies using either the anti-HA antibody or (111)In-octreotide correlated with biodistribution and imaging studies when cell clones expressing different levels of the fusion protein were tested. This approach may be feasible clinically because we were able to discern chimeric gene transfer in tumor-bearing animals with (111)In-octreotide at doses similar to those already used in humans.

CONCLUSION

With this method it may be possible to monitor transfer of a gene of interest directly and noninvasively.

摘要

未标记

基因转移的无创监测将有利于基础研究和患者护理。大多数基因转移成像系统不能直接检测感兴趣的基因，并且大多数未利用已获得美国食品药品监督管理局全身使用批准的放射性药物。（111）铟-奥曲肽在临床上用于定位主要过表达2型生长抑素受体（SSTR2）的肿瘤。我们报告了用这种放射性药物对SSTR2嵌合基因转移进行的体外和体内检测。

方法

将全长SSTR2A连接到5'Igkappa前导序列和血凝素A（HA）序列下游的载体中。然后将载体加插入片段导入HT1080细胞。通过免疫学方法确认Igkappa和HA结构域的功能。在转染细胞中用（111）铟-奥曲肽孵育，同时添加和不添加生长抑素-28来研究受体结合。对携带由转染细胞产生的肿瘤的小鼠注射（111）铟-奥曲肽进行生物分布和成像研究。

结果

通过免疫荧光证实了氨基末端Igkappa结构域在细胞膜上的定位。通过酶联免疫吸附测定、免疫荧光以及用抗HA抗体进行的蛋白质印迹分析鉴定了HA结构域。（111）铟-奥曲肽在体外（受体结合试验）和体内（生物分布研究和γ相机成像）检测到融合蛋白的SSTR2部分。此外，当测试表达不同水平融合蛋白的细胞克隆时，使用抗HA抗体或（111）铟-奥曲肽的体外研究与生物分布和成像研究相关。这种方法在临床上可能是可行的，因为我们能够用与人类已使用剂量相似的（111）铟-奥曲肽在荷瘤动物中辨别嵌合基因转移。