Hauff Peter, Seemann Stefanie, Reszka Regina, Schultze-Mosgau Marcus, Reinhardt Michael, Buzasi Tivadar, Plath Thomas, Rosewicz Stefan, Schirner Michael
Schering, Corporate Research Business Area Diagnostics and Radiopharmaceuticals, Ultrasound & New Modalities Research, Müllerstrasse 178, D-13342 Berlin, Germany.
Radiology. 2005 Aug;236(2):572-8. doi: 10.1148/radiol.2362040870.
To evaluate the feasibility of gene delivery mediated with diagnostic ultrasound and plasmid DNA (pDNA) encapsulated in gas-filled microparticles (GFMP) in rodent tumor models.
This study was performed according to a protocol approved by the regional animal research committee. The model plasmid UT651 (pUT651) that contained the Escherichia coli LacZ gene for beta-galactosidase was used to demonstrate the feasibility of ultrasound-mediated gene delivery in CC531 liver tumors in rats. In preliminary experiments, a single injection of pUT651-containing GFMP was administered intraarterially (n=4) or intravenously (n=6) with simultaneous sonication (color Doppler mode, maximum mechanical index) of the GFMP passing through the capillaries of the tumors. All animals were sacrificed 2-5 days later, and liver tumors were examined for beta-galactosidase expression histochemically. Subsequently, potential medical usefulness of this delivery system was tested in nude mice bearing Capan-1 tumors (adenocarcinoma of the human pancreas) by using the plasmid RC/CMV-p16 (pRC/CMV-p16), which contains tumor suppressor gene p16. The tumor suppressor gene p16 is deleted in Capan-1 cells. Twenty-five tumor-bearing mice were classified into five groups (four to six mice per group, one treatment group, four control groups) at random. All mice were treated once weekly for 5 weeks with intravenous infusion of p16-containing GFMP or control substances with simultaneous tumor sonication with color Doppler mode ultrasound and maximum mechanical index or without ultrasound treatment. The therapeutic effect of p16 was measured as an increase in tumor volume doubling time. Data were analyzed with analysis of variance. Results were considered significant at the 5% critical level (P < .05).
A clear expression of pDNA was found in tumors in rats treated with a combination of pUT651-containing GFMP and ultrasound; relevant controls showed a significantly lower expression of marker gene. The controlled ultrasound-triggered release of pRC/CMV-p16 from GFMP leads to a strong tumor growth inhibition, which is significant (P < .002), compared with that in controls.
A combination of GFMP and ultrasound provides an effective approach for nonviral gene therapy-based cancer treatment.
评估在啮齿动物肿瘤模型中，利用诊断超声和包裹于充气微粒（GFMP）中的质粒DNA（pDNA）介导基因传递的可行性。
本研究按照地区动物研究委员会批准的方案进行。使用含有大肠杆菌β-半乳糖苷酶LacZ基因的模型质粒UT651（pUT651）来证明超声介导的基因传递在大鼠CC531肝肿瘤中的可行性。在初步实验中，单次动脉内注射（n = 4）或静脉内注射（n = 6）含pUT651的GFMP，同时对通过肿瘤毛细血管的GFMP进行超声处理（彩色多普勒模式，最大机械指数）。所有动物在2 - 5天后处死，对肝肿瘤进行β-半乳糖苷酶表达的组织化学检查。随后，通过使用含有肿瘤抑制基因p16的质粒RC/CMV-p16（pRC/CMV-p16），在携带Capan-1肿瘤（人胰腺腺癌）的裸鼠中测试该递送系统的潜在医学实用性。肿瘤抑制基因p16在Capan-1细胞中缺失。将25只荷瘤小鼠随机分为五组（每组四至六只小鼠，一个治疗组，四个对照组）。所有小鼠每周接受一次治疗，共5周，通过静脉输注含p16的GFMP或对照物质，同时用彩色多普勒模式超声和最大机械指数对肿瘤进行超声处理或不进行超声处理。将p16的治疗效果测量为肿瘤体积倍增时间的增加。数据采用方差分析进行分析。结果在5%临界水平（P < .05）被认为具有显著性。
在接受含pUT651的GFMP和超声联合治疗的大鼠肿瘤中发现了pDNA的明显表达；相关对照组显示标记基因的表达明显较低。GFMP对pRC/CMV-p16的超声触发可控释放导致强烈的肿瘤生长抑制，与对照组相比具有显著性（P < .002）。
GFMP和超声的联合应用为基于非病毒基因治疗的癌症治疗提供了一种有效方法。
