^(99m)Tc-MAG_3-ASON的制备及其在荷乳腺癌裸鼠中的分布

Preparation of ^(99m) Tc-MAG_3-ASON and distribution in breast carcinoma-bearing nude mouse model

目的:探讨99mTc标记的反义寡核苷酸(ASON)的制备及其在荷乳腺癌裸鼠中的分布。方法:一步法合成巯基乙酰三甘氨酰-N-羟基琥珀酰亚胺酯(NHS-MAG3),并与c-erbB2 mRNA互补的5’末端氨基修饰的15个碱基的ASON偶联;随后进行99mTc的标记,并用Sephadex G25分离纯化99mTc-MAG3-ASON,并评价其稳定性;最后检测其在荷乳腺癌BALB/c裸鼠体内的分布。结果:99mTc-MAG3-ASON平均标记率为70.6%;纯化后,在室温下放置4h,其放化纯度为94.3%;与人血清孵育后,其放化纯度为93.8%;与血浆蛋白结合率为11.8%。乳腺癌组织的摄取率2h达峰值(6.09%ID/g)。结论:以NHS-MAG3为螯合剂制备的99mTc-MAG3-ASON具有良好的稳定性,在乳腺癌部位高浓聚,可望用于肿瘤的显像诊断和治疗。

Objective：To discuss the preparation of ^99mTc labelled antisense oligonucleotide （ASON） and its distribution in breast carcinoma - bearing nude mouse model. Methods ： N - hydroxysuccinimide ester of mercaptoacetylglycylglycylglycine （ NHS - MAG3 ） was synthesized by one step. A 15 - mer single - stranded phosphorothioate ASON complementary to c erbB2 oncogene mRNA was coupled with NHS- MAG3 and labelled with ^99mTc subsequently. ^99mTc - MAG3 - ASON was purified on a gel filtration column of Sephadex G25, then its stability was evaluated, and finally the distribution was detected in breast carcinoma bearing nude mice model. Results ： The average labeling efficiency of ^99mTc - MAG3 ASON was 70.6 %, and the radiochemical purity was 94.3 % after being labelled at room temperature for 4h. When incubated with fresh human .serum, the radiochmlical purity of 99＇ c - MAG3 ~ was 93.8 %.The serum protein binding of ^99mTc - MAG3 ASON was 11.8 %. The highest uptake of breast carcinoma was 6.09 % ID/g at 2hs.Conclusion ：^99mTc - MAG3-ASON has desirable stability, higher uptake in breast carcinoma and may provide a new sensitive tool for diagnostic imaging and therapy for breast carcinoma in the future.