Glioblastoma (GBM) is a highly aggressive brain cancer with poor clinical outcome. Unfortunately, chemotherapy with temozolomide (TMZ) has a limited efficacy due to resistance mainly attributed to O6-methylguanine methyl transferase (MGMT) activity. Recently, miR-603 and miR-221 have been identified to target MGMT, thus improving the efficacy of temozolomide (TMZ) in the treatment of GBM. Previously, self-assembling nanoparticles (SANPs) have been proposed to deliver miRNAs into the brain. Here, SANP co-encapsulating miRNA-603 (miR-603) and miRNA-221 (miR-221) have been developed to enhance the efficacy of TMZ in the treatment of GBM by preventing the occurrence of chemoresistance. Preliminarily, SANPs encapsulating miRNAs were optimized in terms of lipid composition to assure physical stability and no hemolytic activity. Subsequently, SANPs with the lowest cytotoxicity and excellent internalization efficiency of miRNAs were selected through MTT assay and real-time PCR, respectively. To evaluate a potential synergistic effect between TMZ and miRNAs, MTT and clonogenic assays were performed. In our biological model, miRNA delivery via SANPs in combination with TMZ treatment strongly reduced cell viability and tumorigenic potential. Finally, in vivo assays were carried out on orthotopic xenograft mouse models. The treatment with SANPs encapsulating both miRNAs in combination with TMZ greatly decreased tumour growth, and even more significantly increased animal survival. In conclusion, this strategy provides the rationale for the development of new therapeutic approaches based on SANP technology to deliver miRNAs that play a key role in suppressing tumour.

中文翻译：

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在胶质母细胞瘤中递送 miR-603 和 miR-221 的自组装纳米颗粒作为克服对替莫唑胺耐药的新策略


胶质母细胞瘤 （GBM） 是一种高度侵袭性的脑癌，临床预后较差。不幸的是，替莫唑胺 （TMZ） 化疗的疗效有限，因为耐药性主要归因于 O6-甲基鸟嘌呤甲基转移酶 （MGMT） 活性。最近，miR-603 和 miR-221 已被确定靶向 MGMT，从而提高替莫唑胺 （TMZ） 治疗 GBM 的疗效。以前，自组装纳米颗粒 （SANP） 已被提议将 miRNA 递送到大脑中。在这里，已经开发了 SANP 共封装 miRNA-603 （miR-603） 和 miRNA-221 （miR-221），通过防止化疗耐药的发生来增强 TMZ 治疗 GBM 的疗效。初步，封装 miRNAs 的 SANPs 在脂质组成方面进行了优化，以确保物理稳定性和无溶血活性。随后，分别通过 MTT 检测和实时 PCR 筛选出 miRNAs 细胞毒性最低、内化效率优异的 SANPs。为了评估 TMZ 和 miRNAs 之间的潜在协同作用，进行了 MTT 和克隆形成测定。在我们的生物模型中，通过 SANPs 递送 miRNA 与 TMZ 处理相结合，大大降低了细胞活力和致瘤潜力。最后，对原位异种移植小鼠模型进行体内测定。用封装两种 miRNA 的 SANPs 与 TMZ 联合治疗大大减少了肿瘤生长，甚至更显着地提高了动物存活率。总之，该策略为开发基于 SANP 技术的新治疗方法提供了基本原理，以提供在抑制肿瘤中起关键作用的 miRNA。