99mTc-peptide-peptide nucleic acid probes for imaging oncogene mRNAs in tumours
99mTc-peptide-peptide nucleic acid probes for imaging oncogene mRNAs in tumours
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DOI：
10.1097/01.mnm.0000084583.29433.df
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发表时间：
2003-08-01
影响因子：
1.5
通讯作者：
Wickstrom, E
中科院分区：
文献类型：
--
作者：
Rao, PS;Tian, X;Wickstrom, E
肿瘤中癌基因mRNA的成像将为早期发现隐匿性恶性病变提供有力的工具。目的是制备一种嵌合体，该嵌合体由一种十二聚体反义肽核酸（PNA）和一种螯合片段组成，该片段对人乳腺癌细胞中过度表达的c-MYC癌基因具有特异性，该片段有利于用Tc-99m进行定量放射性标记，并评估其在实验动物中的杂交和组织分布。c-MYC mRNA特异性的五肽螯合剂- pna十二聚体通过9-氟酰甲基羰基（Fmoc）偶联从固体载体扩展而来。同样，也制备了一个具有四个中心错配的螯合剂- pna嵌合体作为对照。对嵌合体进行纯化、鉴定，并用荧光实时聚合酶链反应（RT-PCR）与c-MYC mRNA杂交。嵌合体用Tc-99m标记，并在携带实验性人类乳腺肿瘤的胸腺裸鼠中检测其组织分布。Tc-99m放射性标记是定量的，在反相液相色谱中呈单峰。使用引物和先前计算的c-MYC mRNA荧光探针组进行荧光实时聚合酶链反应显示，与对照组相比，c-MYC特异性嵌合体对逆转录有抑制作用。在给药后4小时和24小时的组织分布研究显示，反义和错配嵌合体在肝脏中有适度的积累，在肿瘤中也有可观的水平。这些观察结果表明Tc-99m-peptide-PNA探针可能对肿瘤基因表达成像有用，该方法值得进一步研究。(C) 2003 Lippincott Williams Wilkins)。
Imaging oncogene mRNA in tumours would provide a powerful tool for the early detection of occult malignant lesions. The goal was to prepare a chimera consisting of a dodecamer antisense peptide nucleic acid (PNA) specific for c-MYC oncogene overexpressed in human breast cancer cells and a chelating moiety that facilitates quantitative radiolabelling with Tc-99m and evaluate it for hybridization and tissue distribution in laboratory animals. The pentapeptide chelator-PNA dodecamer specific for c-MYC mRNA was extended from a solid support by 9-fluorenylmethyloxycarbonyl (Fmoc) coupling. Similarly, a chelator-PNA chimera with four central mismatches was also prepared which served as a control. The chimeras were purified, characterized and evaluated for hybridization to c-MYC mRNA by fluorescent, real-time polymerase chain reaction (RT-PCR). The chimeras were labelled with Tc-99m and their tissue distribution was examined in athymic nude mice bearing experimental human breast tumours. Tc-99m radiolabelling was quantitative and presented a single peak in reversed phase liquid chromatography. Fluorescent real-time polymerase chain reactions using primer and fluorescent probe sets previously calculated for c-MYC mRNA demonstrated inhibition of reverse transcription by the c-MYC specific chimera as compared to that of the control. Tissue distribution studies of antisense and mismatch chimeras at 4 h and 24 h after administration displayed modest accumulation in the liver, and appreciable levels in tumours. These observations suggest that Tc-99m-peptide-PNA probes might be useful for imaging gene expression in tumours, and the approach is worthy of further investigation. ((C) 2003 Lippincott Williams Wilkins).