In vivo hybridization of technetium-99m-labeled peptide nucleic acid (PNA).
In vivo hybridization of technetium-99m-labeled peptide nucleic acid (PNA).
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发表时间：
1997-06
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影响因子：
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通讯作者：
G. Mardirossian;K. Lei;M. Rusckowski;F. Chang;T. Qu;M. Egholm;D. Hnatowich
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文献类型：
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作者：
G. Mardirossian;K. Lei;M. Rusckowski;F. Chang;T. Qu;M. Egholm;D. Hnatowich
放射性标记的单链DNA寡核苷酸与其单链互补序列在体内的非标记杂交尚未得到令人信服的证明。一个影响因素可能是磷酸二酯和硫代磷酸酯DNA的体内不利性质。肽核酸（PNA）寡聚物已被报道具有更适合于放射性药物应用的体内性质。方法用99 mTc通过修饰的MAG 3螯合剂标记了胺衍生的15碱基PNA寡聚体。结果PNA在体外与其补体杂交的能力在偶联和放射性标记后似乎没有受到损害。孵育24小时后，对37 ℃血清进行分子排阻、高效液相色谱（HPLC）分析，结果显示放射性标记主要以标记的PNA形式存在，并指示标记的血清蛋白和低分子量分解代谢产物。小鼠全身清除迅速，50%的标签消除约2小时后，2.5小时，最高摄取量（肾脏）只有1.5%的注射剂量/克，低于0.07%/克存在于所有采样组织在24小时。为了评估体内杂交，珠皮下植入正常小鼠的两条大腿。仅在左大腿中，珠与互补单链PNA缀合。在腹膜内给予标记的PNA后23小时，左/右大腿放射性比为6：1。此时的全身图像仅显示膀胱、肾脏和左大腿。结论99 mTc-PNA与本实验室研究的放射性标记DNA不同，具有稳定性和药代动力学特性，适合作为放射性药物使用。
UNLABELLED Hybridization of a radiolabeled single-stranded DNA oligonucleotide with its single-stranded complement in vivo has not yet been convincingly demonstrated. A contributing factor may be unfavorable in vivo properties of the phosphodiester and phosphorothioate DNAs. Peptide nucleic acid (PNA) oligomers have been reported to possess in vivo properties more suitable for radiopharmaceutical applications. METHODS We have radiolabeled an amine-derivatized 15-base PNA oligomer with 99mTc through a modified MAG3 chelator. RESULTS The ability of the PNA to hybridize in vitro with its complement appeared to be unimpaired after conjugation and radiolabeling. Size-exclusion, high-performance liquid chromatography (HPLC) analysis of 37 degrees C serum after 24 hr of incubation showed the radiolabel to be present predominately as labeled PNA with indications of labeled serum proteins and a low molecular weight catabolite. Whole-body clearance in mice was rapid, with 50% of the label eliminated in about 2 hr. After 2.5 hr, the highest uptake (kidneys) was only 1.5% of the injected dose/g; less than 0.07%/g was present in all sampled tissues at 24 hr. To evaluate in vivo hybridization, beads were implanted subcutaneously in both thighs of normal mice. In the left thigh only, the beads were conjugated with complementary single-stranded PNA. At 23 hr following intraperitoneal administration of the labeled PNA, the left/right thigh radioactivity ratio was 6:1. Whole-body images at this time showed only bladder, kidneys and the left thigh. CONCLUSION Unlike the radiolabeled DNAs investigated in this laboratory, 99mTc-PNA displays stability and pharmacokinetic properties suitable for eventual use as radiopharmaceuticals.