Département de Transfert, Institut Curie, Orsay, France.
Cancer Gene Ther. 2011 Oct;18(10):695-706. doi: 10.1038/cgt.2011.39. Epub 2011 Jul 29.
Introducing small DNA molecules (Dbait) impairs the repair of damaged chromosomes and provides a new method for enhancing the efficiency of radiotherapy in radio-resistant tumors. The radiosensitizing activity is dependent upon the efficient delivery of Dbait molecules into the tumor cells. Different strategies have been compared, to improve this key step. We developed a pipeline of assays to select the most efficient nanoparticles and administration protocols before preclinical assays: (i) molecular analyses of complexes formed with Dbait molecules, (ii) cellular tests for Dbait uptake and activity, (iii) live zebrafish embryo confocal microscopy monitoring for in vivo distribution and biological activity of the nanoparticles and (iv) tumor growth and survival measurement on mice with xenografted tumors. Two classes of nanoparticles were compared, polycationic polymers with linear or branched polyethylenimine (PEI) and covalently attached cholesterol (coDbait). The most efficient Dbait transfection was observed with linear PEI complexes, in vitro and in vivo. Doses of coDbait ten-fold higher than PEI/Dbait nanoparticles, and pretreatment with chloroquine, were required to obtain the same antitumoral effect on xenografted melanoma. However, with a 22-fold lower 'efficacy dose/toxicity dose' ratio as compared with Dbait/PEI, coDbait was selected for clinical trials.
引入小 DNA 分子（Dbait）可损害受损染色体的修复，并为提高放射抗拒肿瘤的放射治疗效率提供新方法。放射增敏活性取决于 Dbait 分子有效递送至肿瘤细胞。为了改进这一关键步骤，我们比较了不同的策略。在进行临床前研究之前，我们开发了一系列的检测方法来选择最有效的纳米颗粒和给药方案：（i）与 Dbait 分子形成的复合物的分子分析，（ii）Dbait 摄取和活性的细胞测试，（iii）用于体内分布和纳米颗粒生物学活性的活体斑马鱼胚胎共聚焦显微镜监测，以及（iv）荷异种移植瘤小鼠的肿瘤生长和存活测量。我们比较了两类纳米颗粒，即带有线性或支化聚乙二烯亚胺（PEI）的阳离子聚合物和共价连接胆固醇（coDbait）。在线性 PEI 复合物中，无论是在体外还是体内，都观察到 Dbait 转染效率最高。与 PEI/Dbait 纳米颗粒相比，需要使用 coDbait 十倍高的剂量，并且用氯喹预处理，才能在异种移植黑素瘤中获得相同的抗肿瘤效果。然而，与 Dbait/PEI 相比，coDbait 的“疗效剂量/毒性剂量”比值低 22 倍，因此被选择进行临床试验。
