Imaging hNET reporter gene expression with 124I-MIBG
Imaging hNET reporter gene expression with 124I-MIBG
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DOI：
10.2967/jnumed.106.037812
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发表时间：
2007-05-01
影响因子：
9.3
通讯作者：
Blasberg, Ronald G.
中科院分区：
文献类型：
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作者：
Moroz, Maxim A.;Serganova, Inna;Blasberg, Ronald G.
去甲肾上腺素转运蛋白（NET）最近被认为是一种有用的报告基因。我们通过构建用于核成像和光学成像的内部核糖体进入位点（IRES）连接的 hNET-绿色荧光蛋白（GFP）混合报告基因来扩展这项工作。方法：构建逆转录病毒载体pQCXhNET-IRES-GFP，并用于产生几种报告细胞系和异种移植物。转导的细胞通过基于 GFP 表达的荧光激活细胞分选进行分选，并用于体外和体内成像研究。结果：与野生型亲本细胞系相比，转导的报告细胞积累了高水平的 I-123 或 I-124 标记的间碘苄胍 (MIBG)。细胞系之间 MIBG 积累的差异主要是由于流入 (K-1) 而非流出 (k(2)) 的差异。转导的 Jurkat、C6 和 COS-7 细胞的估计 MIBG 分布体积 (V-d) 分别为 572 +/- 13、754 +/- 25 和 1,556 +/- 38 mL/g。放射性示踪剂积累 (K1) 和 GFP 荧光强度之间的相关性也得到了证明。对携带 pQCXhNET-IRES-GFP 转导的小鼠和野生型 C6 异种移植物的连续成像研究表明，与 I-123-MIBG 伽马相机/SPECT 相比，I-124-MIBG 小动物 PET 具有多种优势。这主要是由于 124 1 的半衰期较长，以及与野生型异种移植物（半衰期，12 +/- 1 小时）和其他器官（半衰期，2.6-21 小时）相比，转导的异种移植物中的 MIBG 保留且清除缓慢（半衰期，63 +/- 6 小时）。在后来的成像时间中观察到非常高的放射性比率；注射 I-124-MIBG 后 73 小时，C6/hNET-IRES-GFP 异种移植物与肌肉的比率为 293 +/- 48，而 C6 异种移植物与肌肉的比率为 0.71 +/- 0.19。结论：这些研究证明了 hNET 报告成像的更广泛应用的潜力，以及未来使用目前可用于 SPECT 和 PET 的放射性药物转化为患者研究的潜力。
The norepinephrine transporter (NET) has recently been suggested as a useful reporter gene. We have extended this effort by constructing an internal ribosomal entry site (IRES)-linked hNET-green fluorescent protein (GFP) hybrid reporter gene for both nuclear and optical imaging. Methods: A retroviral vector pQCXhNET-IRES-GFP was constructed and used to generate several reporter cell lines and xenografts. Transduced cells were sorted by fluorescence-activated cell sorting based on GFP expression and used for both in vitro and in vivo imaging studies. Results: The transduced reporter cells accumulated I-123- or I-124-labeled metaiodobenzylguanidine (MIBG) to high levels compared with the wild-type parent cell lines. Differences in MIBG accumulation between cell lines were primarily due to differences in influx (K-1) rather than efflux (k(2)). The estimated MIBG distribution volumes (V-d) for transduced Jurkat, C6, and COS-7 cells were 572 +/- 13, 754 +/- 25, and 1,556 +/- 38 mL/g, respectively. A correlation between radiotracer accumulation (K1) and GFP fluorescence intensity was also demonstrated. Sequential imaging studies of mice bearing pQCXhNET-IRES-GFP transduced and wild-type C6 xenografts demonstrated several advantages of I-124-MIBG small-animal PET compared with I-123-MIBG gamma-camera/SPECT. This was primarily due to the longer half-life of 124 1 and to the retention and slow clearance (half-time, 63 +/- 6 h) of MIBG from transduced xenografts compared with that from wild-type xenografts (half-time, 12 +/- 1 h) and other organs (half-time, 2.6-21 h). Very high radioactivity ratios were observed at later imaging times; at 73 h after I-124-MIBG injection, the C6/hNET-IRES-GFP xenograft-to-muscle ratio was 293 +/- 48 whereas the C6 xenograft-to-muscle ratio was 0.71 +/- 0.19. Conclusion: These studies demonstrate the potential for a wider application of hNET reporter imaging and the future translation to patient studies using radiopharmaceuticals that are currently available for both SPECT and PET.