Telomerase-Mediated Self-Assembly of DNA Network in Cancer Cells Enabling Mitochondrial Interference.

The precise control of the artificially induced reactions inside living cells is emerging as an effective strategy for the regulation of cell functions. Nevertheless, the manipulation of the assembly of exogenous molecules into artificial architectures in response to intracellular-specific signals remains a grand challenge. Herein, we achieve the precise self-assembly of deoxyribonucleic acid (DNA) network inside cancer cells, specifically responding to telomerase, and realize effective mitochondrial interference and the consequent regulation of cellular behaviors. Two functional DNA modules were designed: a mitochondria-targeting branched DNA and a telomerase-responsive linear DNA. Upon uptake by cancer cells, the telomerase primer in linear DNA responded to telomerase, and a strand displacement reaction was triggered by the reverse transcription of telomerase, thus releasing a linker DNA from the linear DNA. The linker DNA afterward hybridized with the branched DNA to form a DNA network on mitochondria. The DNA network interfered with the function of mitochondria, realizing the apoptosis of cancer cells. This system was further administered in a nude mouse tumor model, showing remarkable suppression of tumor growth. We envision that the telomerase-mediated intracellular self-assembly of the DNA network provides a promising route for cancer therapy.

A Smart DNA-Based Nanosystem Containing Ribosome-Regulating siRNA for Enhanced mRNA Transfection.

Messenger RNA (mRNA) transfection is the prerequisite for the application of mRNA-based therapeutics. In hard-to-transfect cells, such as macrophages, the effective transfection of mRNA remains a long-standing challenge. Herein, a smart DNA-based nanosystem is reported containing ribosome biogenesis-promoting siRNA, realizing efficient mRNA transfection in macrophages. Four monomers are copolymerized to form a nanoframework (NF), including N-isopropylacrylamide (NIPAM) as the skeleton and acrydite-DNA as the initiator to trigger the cascade assembly of DNA hairpins (H1-polyT and H2-siRNA). By virtue of the phase transition characteristic of polymeric NIPAM, below the lower critical solution temperature (LCST, ≈34 °C), the NF swells to expose polyT sequences to hybridize with the polyA tail of mRNA. Above the LCST, the NF deswells to encapsulate mRNA. The disulfide bond in the NF responds to glutathione, triggering the disassembly of the nanosystem; the siRNA and mRNA are released in response to triphosadenine and RNase H. The siRNA down-regulates the expression of heat shock protein 27, which up-regulates the expression of phosphorylated ribosomal protein S6. The nanosystem shows satisfactory mRNA transfection and translation efficiency in a mouse model. It is envisioned that the DNA-based nanosystem will provide a promising carrier to deliver mRNA in hard-to-transfect cells and promote the development of mRNA-based therapeutics.

Lysosome Interference Enabled by Proton-Driven Dynamic Assembly of DNA Nanoframeworks inside Cells.

Coupling materials chemistry systems to biological processes is a promising way to rationally modulate lysosomal functions. A proton-driven dynamic assembly of a DNA nanoframework inside cells coupled with the lysosome-mediated endocytosis pathways/lysosomal maturation, gives the rational modulation of lysosomal functions, which we term "lysosome interference". Through lysosome-mediated endocytosis, the DNA nanoframework with acid-responsive semi-i-motif enters the lysosome and assembles into an aggregate in a process triggered by lysosomal acidity. The aggregate is suitable for long-term retention. The consumption of protons resulted in lysosomal acidity reduction and hydrolase activity attenuation, thus hindering the degradation of nucleic acid drugs in the lysosome and improving gene silencing effects. This study shows a new way to achieve lysosome interference by coupling the subcellular microenvironment with a precisely programmable assembly system.

Construction of rolling circle amplification-based DNA nanostructures for biomedical applications.

DNA-based materials exhibit great potential in biomedical applications due to their excellent sequence programmability and unique functional designability. Rolling circle amplification (RCA) is an efficient isothermal enzymatic amplification strategy to produce ultralong single-stranded DNA with customized functional moieties. The rational design of RCA templates and the introduction of other functional components enable RCA-based DNA materials with structural dynamic responsiveness and diverse biological functions, facilitating the development of DNA-based materials in biomedical applications. In this review, the principle and synthetic methods of RCA and the recent progress of RCA-based DNA nanostructures for therapeutics and bioimaging are summarized and discussed. The future challenges and opportunities for RCA-based DNA nanostructures are discussed at the end of the study. We envision that the development of RCA-based DNA nanostructures will provide more possibilities for precision medicine.

Dynamic Transformation of DNA Nanostructures inside Living Cells.

DNA nanostructures, that show sequence programmable responsiveness to intracellular signals, have been explored as potential candidates of artificial dynamic functional structures in living cells. Recently, we developed a series of intracellular signals responding DNA nanostructures in living cells to perform a special mission. In this review, the developed DNA nanostructures and their dynamic transformation properties are summarized and discussed. The DNA nanostructures are generally categorized into DNA-inorganic nanomaterials and DNA-organic nanomaterials depending on the composition. At the end of this review, the challenges and prospects on instructing dynamic DNA nanostructures in living cells are discussed. We believe that this review will contribute to the further development of stimuli-responsive nanomaterials, which is of great potential in biomedical applications.

DNA Functional Nanomaterials for Controlled Delivery of Nucleic Acid-Based Drugs.

Nucleic acid-based drugs exhibited great potential in cancer therapeutics. However, the biological instability of nucleic acid-based drugs seriously hampered their clinical applications. Efficient in vivo delivery is the key to the clinical application of nucleic acid-based drugs. As a natural biological macromolecule, DNA has unique properties, such as excellent biocompatibility, molecular programmability, and precise assembly controllability. With the development of DNA nanotechnology, DNA nanomaterials have demonstrated significant advantages as delivery vectors of nucleic acid-based drugs by virtue of the inherent nucleic acid properties. In this study, the recent progress in the design of DNA-based nanomaterials for nucleic acid delivery is summarized. The DNA nanomaterials are categorized according to the components including pure DNA nanomaterials, DNA-inorganic hybrid nanomaterials, and DNA-organic hybrid nanomaterials. Representative applications of DNA nanomaterials in the controlled delivery of nucleic acid-based drugs are exemplified to show how DNA nanomaterials are rationally and exquisitely designed to address application issues in cancer therapy. At the end of this study, the challenges and future development of DNA nanomaterials are discussed.

Supramolecular Self-Assembled DNA Nanosystem for Synergistic Chemical and Gene Regulations on Cancer Cells.

Incorporating multiple molecular interactions within a system to realize the metabolic reprogramming of cancer cells is prospected to be of great potential in cancer therapy. Herein, we report a supramolecular self-assembled DNA nanosystem, which reprogrammed the cellular antioxidant system via synergistic chemical and gene regulations. In the nanosystem, amphipathic telluroether was coordinated with MnII to self-assemble into micelle, on which a siNrf2 integrated DNA network was assembled. The great electron-donating capability of telluroether was revealed to greatly promote MnII -based Fenton-like reaction to generate subversive . OH in cancer cells. In response to adenosine triphosphoric acid, the siNrf2 was specially released in cytoplasm for down-regulating expression of detoxification enzymes, which enhanced chemocatalysis-mediated oxidative stress in cancer cells, thus significantly suppressing tumor progression.