Vectorologie et thérapeutiques anti-cancéreuses, CNRS UMR 8203, Université Paris Sud 11, Institut Gustave Roussy, Villejuif, France.
PLoS One. 2012;7(12):e52207. doi: 10.1371/journal.pone.0052207. Epub 2012 Dec 20.
Small interfering RNAs (siRNAs) are powerful tools commonly used for the specific inhibition of gene expression. However, vectorization is required to facilitate cell penetration and to prevent siRNA degradation by nucleases. We have shown that diamond nanocrystals coated with cationic polymer can be used to carry siRNAs into Ewing sarcoma cells, in which they remain traceable over long periods, due to their intrinsic stable fluorescence. We tested two cationic polymers, polyallylamine and polyethylenimine. The release of siRNA, accompanied by Ewing sarcoma EWS-Fli1 oncogene silencing, was observed only with polyethylenimine. We investigated cell penetration and found that the underlying mechanisms accounted for these differences in behavior. Using drugs selectively inhibiting particular pathways and a combination of fluorescence and electronic microscopy, we showed that siRNA gene silencing occurred only if the siRNA:cationic nanodiamond complex followed the macropinocytosis route. These results have potential implications for the design of efficient drug-delivery vectors.
小干扰 RNA（siRNA）是一种常用于特异性抑制基因表达的强大工具。然而，为了促进细胞穿透和防止核酸酶降解 siRNA，需要进行载体化。我们已经表明，用阳离子聚合物涂覆的金刚石纳米晶体可用于将 siRNA 带入尤文肉瘤细胞中，由于其固有的稳定荧光，它们可以在很长一段时间内被追踪。我们测试了两种阳离子聚合物，聚烯丙胺和聚乙烯亚胺。只有聚乙烯亚胺观察到 siRNA 的释放，同时伴随着尤文肉瘤 EWS-Fli1 癌基因的沉默。我们研究了细胞穿透情况，并发现导致这些行为差异的潜在机制。我们使用选择性抑制特定途径的药物以及荧光和电子显微镜的组合，表明只有当 siRNA：阳离子纳米金刚石复合物遵循巨胞饮途径时，siRNA 基因沉默才会发生。这些结果对于设计有效的药物输送载体具有潜在意义。
