小鼠双微体扩增基因反义探针用于荷人前列腺癌裸鼠的显像研究

Antisense imaging targeting mouse double minute 2 oncogene in prostate cancer xenografts

目的探讨^99Tc^m标记针对小鼠双微体扩增基因（MDM2）mRNA的ASON（MDM2反义探针）用于前列腺癌无创性基因显像的价值。方法以HYNIC为螯合物，对含MDM2mRNA某段序列的ASON、错义寡核苷酸（ASONM）进行^99Tc^m标记，检测标记率及放化纯。建立荷人前列腺癌LNCaP裸鼠肿瘤模型，分为3组（每组10只），进行^99Tc^m-HYNIC—ASON和^99Tc^mHYNIC—ASONM、^99Tc^mO4^-（对照）肿瘤显像。测量肿瘤／对侧肢体（T／M）比值，采用单因素方差分析对测量数据进行统计学分析。结果ASON的^99Tc^m标记率为（65．15±2．05）％，ASONM的^99Tc^m标记率为（64．93±2．18）％。^99Tc^m-HYNIC—ASON和^99Tc^m-HYNIC—ASONM经纯化后，放化纯均达90％以上。不同探针注射后1、4和10h时，^99Tc^m-HYNIC—ASON组T／M比值分别为3．217±0．125、3．749±0．201和4．028~0．186；^99Tc^m HYNIC—ASONM组分别为1．579±0．128、1．715±1．140和1．683±0．139；对照组分别为2．146±0．132、1．847±0．124和1．528±0．152.^99Tc^m-HYNIC—ASON1、4、10hT／M比值与对照组和错义组差异均有统计学意义（F=213．37～235．41，t=3．527～4．738，均P〈0．01），而^99Tc^m-HYNIC—ASONM组各T／M比值与对照组差异均无统计学意义（t=2．154、2．287和2．236，均P〉0．05）。结论^99Tc^m标记的MDM2反义探针可在荷人前列腺癌裸鼠模型的肿瘤组织中特异性聚集，可以在早期对前列腺癌进行无创性的基因诊断。

Objective To explore the value of antisense imaging of ^99Tc^m-labeled ASON targeting mouse double minute 2（MDM2） mRNA for the diagnosis of human prostate cancer. Methods The ASON targeting MDM2 mRNA and the mismatched oligonucleotide （ASONM） were synthesized and radiolabeled with 99TCm using the bifunctional chelator HYNIC. The labeling efficiency and radiochemical purity were investigated. Animal models of nude mice bearing human prostate cancer LNCaP were established and divided into 3 groups with 10 mice in each group. 99Tcm-HYNIC-ASON, ^99Tc^m-HYNIC-ASONM （study groups） and ^99Tc^m-O4^-（ control group） were injected at the dose of 7.4 MBq through the tail vein, respectively. Tumor imaging was acquired with SPECT and the tumor-to-muscle （T/M） ratio was measured. The data was compared by one-way analysis of variance. Results The labeling efficiencies of ASON and ASONM were （ 65. 15±2.05 ） % and （ 64.93±2.18 ） %, respectively. Their radiochemical purity was greater than 90%. At 1, 4 and 10 h post injection, the T/M ratios of 99Tcm-HYNIC-ASON group were 3.217±0.125, 3.749± 0. 201 and 4.028＋0.186, and those of 99Tcm-HYNIC-ASONM group were 1.579±0.128, 1.715±1.140 and 1.683±0.139, and control group 2.146±0.132, 1.847±0.124, 1.528±0.152, respectively. The T/M ratios in control group and ^99Tc^m-HYNIC-ASONM group were significantly lower than those in ^99Tc^m-HYNIC- ASON group at 1, 4 and 10 h, respectively （F=213.37-235.41, t=3.527-4.738; all P〈0.01）. The T/M ratios of ^99Tc^m-HYNIC-ASONM group and control group were not significantly different at 1, 4 and 10 h （t = 2.154, 2.287 and 2.236, all P〉0.05）. Conclusion The antisense probe of MDM2 can accumulate specifically in prostate cancer tissue in animal models, which might be useful as a non-invasive genetic tool for the early diagnosis of prostate cancer.