摘要
目的建立99mTc标记寡核苷酸的方法并用于荷乳腺癌小鼠反义寡核苷酸显像研究。方法利用双功能螯合剂N-羟基琥珀酰亚胺-巯乙苷肽(S-Acetyl-NHS-MAG3)对一段15碱基c-mycmRNA反义寡核苷酸片段进行99mTc标记;对荷乳腺癌昆明种小鼠进行标记反义寡核苷酸生物学分布与显像研究。结果生物学分布结果表明,相对于正义核酸而言,反义核酸在肿瘤组织中的摄取明显增高(P<0.05)。在反义寡核苷酸显像组,肿瘤组织显像剂摄取活跃,肿瘤/肌肉比值最高可达5.5。在正义寡核苷酸显像组及阻断组,肿瘤组织均未出现明显的显像剂浓聚。结论99mTc标记反义寡核苷酸有望成为一种新的显像剂,在分子水平上用于恶性肿瘤的早期、特异和无创性诊断。
Objective To establish the methods for Technetium-99m （99mTc） labeled antisense oligonucleotides used for antisense oligonucleotides imaging in breast tumor mice. Methods The 15-mer oligonucleotide sequence was synthesized, aminolinked （sense and antisense phosphodiester） and conjugated with S-Acetyl-NHS-MAG3 by a N-hydroxy-succinimide derivative. The purified MAG3-DNA was radiolabeled with ^99mTc by transchelation from sodium tartrate and free ^99mTc was separated by gel filtration. The radiolabeled antisense and sense probes were injected intravenously in breast tumor-bearing Kunming mice （1 × 10^6 cells, 6 days after inoculation）. Biodistribution was studied and the mice were imaged. Results Essentially complete conjugation was achieved by reverse-phase Sep-Pak C18 chromatography analysis. The MAG3-DNA was labeled with ^99mTc at room temperature and neutral pH, with a mean labeling efficiency of 80.11% （s. d=2.96%, n=4）. After labeling, the stability of the DNA in saline was retained as determined by reverse-phase Sep-Pak C18 chromatography analysis. Biodistribution studies revealed higher accumulation of antisense probes in tumor tissue than that of sense probes. In the antisense group, the tumor was clearly imaged since 30 min and the highest tumor to muscle ratio of 5.5 was obtained at 4 h post-injection. Positive imaging was not obtained in control group （in which non-conjugated, non-labeled antisense oligonucleotede was administered 2 h before radiolabeled antisense probes were injected） and sense group. Conclusion The ^99mTc labeled antisense probe may provide a sensible and specific tool for noninvasive imaging of e-myc oncogene mRNA for a variety of malignant tumors at an earlier stage.
出处
《华中科技大学学报（医学版）》
CAS
CSCD
北大核心
2008年第3期372-376,共5页
Acta Medicinae Universitatis Scientiae et Technologiae Huazhong
基金
国家自然科学基金资助项目(No30070310)
