State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecule Engineering of Hunan Province, Hunan University, Changsha 410082, China.
Anal Chem. 2021 Oct 19;93(41):13919-13927. doi: 10.1021/acs.analchem.1c02907. Epub 2021 Oct 8.
The development of multifunctional nanoplatforms that integrate both diagnostic and therapeutic functions has always been extremely desirable and challenging in the cancer combat. Here, we report an endogenous miRNA-activated DNA nanomachine (EMDN) in living cells for concurrent sensitive miRNA imaging and activatable gene silencing. EMDN is constructed by interval hybridization of two functional DNA monomers (R/HP and F) to a DNA nanowire generated by hybridization chain reaction. After the target cell-specific transportation of EMDN, intracellular let-7a miRNA initiates the DNA nanomachine by DNA strand displacement cascades, resulting in an amplified fluorescence resonance energy-transfer signal and the release of many free HP sequences. The restoration of HP hairpin structures further activates the split-DNAzyme to identify and cleave the EGR-1 mRNA to realize gene silencing therapy. The proposed EMDN shows efficient cell internalization, good biological stability, rapid reaction kinetics, and the ability to avoid false-positive signals, thus ensuring reliable miRNA imaging in living cells. Meanwhile, the controlled activation of the split-DNAzyme activity regulated by the intracellular specific miRNA may be promising in the precise treatment of cancer. Collectively, this strategy provides a valuable nanoplatform for early clinical diagnosis and activatable gene therapy of tumors.
在癌症治疗中，开发集诊断和治疗功能于一体的多功能纳米平台一直是非常理想和具有挑战性的。在这里，我们报告了一种内源性 miRNA 激活的 DNA 纳米机（EMDN），可用于同时进行敏感的 miRNA 成像和可激活的基因沉默。EMDN 由两个功能 DNA 单体（R/HP 和 F）间隔杂交到杂交链式反应产生的 DNA 纳米线上构建而成。在 EMDN 被靶向细胞特异性运输后，细胞内的 let-7a miRNA 通过 DNA 链置换级联反应启动 DNA 纳米机，导致放大的荧光共振能量转移信号和许多游离的 HP 序列的释放。HP 发夹结构的恢复进一步激活了分裂 DNA 酶，以识别和切割 EGR-1 mRNA，从而实现基因沉默治疗。所提出的 EMDN 表现出高效的细胞内化、良好的生物稳定性、快速的反应动力学以及避免假阳性信号的能力，从而确保了在活细胞中进行可靠的 miRNA 成像。同时，由细胞内特异性 miRNA 调节的分裂 DNA 酶活性的可控激活，可能在癌症的精确治疗中具有广阔的前景。总的来说，该策略为肿瘤的早期临床诊断和可激活基因治疗提供了一个有价值的纳米平台。
