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Herein, we report on the design of a programmable DNA ribbon using long‐chain DNA molecules with a user‐defined repetitive padlock sequence. The DNA ribbon can be further combined with gold nanoparticles (AuNPs) to create a composite nanomaterial that contains an AuNP core and a high‐density DNA crown carrying a cancer‐cell‐targeting DNA aptamer, a fluorescent tag for location tracking, and a cell‐killing drug. This composite material can be efficiently internalized by cancer cells and its cellular location can be tracked by fluorescence imaging. The system offers several attractive characteristics, including simple design, tunable DNA crown, high drug‐loading capacity, selective cell targeting, and pH‐sensitive drug release. These features make such a material a promising therapeutic agent. [ABSTRACT FROM AUTHOR]

Abstract Herein, DNA nanostructures were prepared via a palindromic padlock probe-based rolling circle amplification (called P-RCA) and then employed to implement the sensitive and specific detection of let-7a miRNA extracted from cancer cells without chemical modification. The presence of target let-7a miRNA as a polymerization primer can trigger the P-RCA process, generating a long tandemly repetitive DNA strand. The resulting products can fold into nanostructures via self-hybridization of palindromic regions and possess numerous double-stranded fragments. In this case, the strong fluorescent signal is detected upon exposure to SYBR Green I. As a result, in homogeneous solution, target miRNA can be detected down to 6.4 pM with a wide dynamic range. A high specificity was demonstrated by the excellent discrimination between let-7 miRNA family members, while the applicability of this sensing system in complex biological environments was confirmed by the analysis of target miRNAs extracted from HeLa cells. It should be noted that increasing numbers of palindromic fragments in padlock probe further increases signal amplification efficiency. The experimental results indicate that the newly proposed P-RCA DNA nanostructures have potential to become a promising analytical platform in biomedical research and clinical diagnosis for the miRNA detection with high sensitivity and good specificity. Graphical abstract Palindromic DNA sequences and RCA were used to create new DNA nanostructures that can execute the amplification detection of target miRNA (let-7a miRNA) in vitro. fx1 Highlights • Palindromic DNA sequences and RCA were used to create new DNA nanostructures for target miRNA detection. • This as-prepared P-RCA nanostructures achieved a high sensitivity for let-7a miRNA detection. • The difference between let-7 miRNA family members was able to be readily distinguished. • The P-RCA DNA nanostructures could be applied for the analysis of let-7a miRNA extracted from HeLa cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • An intracellular invasive growth of DNA hydrogel network (2 h-DNH) from two DNAs. • The invasion of malignant tumors is predicted by visualizing intracellular 2 h-DNH. • Therapeutic intervention before clinical symptoms' appearance hampers tumorigenesis. DNA structural nanotechnology is of significant importance for the understanding, diagnosis and treatment of human diseases. However, few reports have examined whether DNA structural nanotechnology can be suitable for predicting the malignant invasion of tumor cells and preventing cancers. It is mainly because complex design of numerous DNA building blocks and susceptibility of nanostructures, including DNA hydrogels, to nuclease degradation as critical issues hamper the transition to clinical application. Moreover, intracellular assembly of DNA nanostructures in a very simple manner is unexplored because of technical limitations. In current study, by palindromic end-mediated cross-linking hybridization chain reaction (c-HCR), we report intracellular invasive growth of DNA hydrogel network (2 h-DNH) from only two hairpins in a sequential manner, where the palindromic fragment in DNA building blocks substantially simplifies the probe design and assembly process. Macroscopic 2 h-DNH can be visualized by naked eye and remain its structural integrity over 12-h incubation in intracellular environment. The c-HCR strategy can be used to screen intracellular miRNAs with the detection sensitivity improved by almost 2 ~ 3 orders of magnitude. Diseased cells (HeLa) are discriminated from healthy cells (HEK-293), and MCF-7 cells with different levels of miR-21 are accurately identified. Even without clinical symptoms, the invasion of malignant tumor cells is predicted by visualizing intracellular 2 h-DNH. Moreover, c-HCR-guided therapeutic intervention can hamper the tumorigenesis, indicating the great potential application in the early warning and prevention of human cancers. [ABSTRACT FROM AUTHOR]

Surface proteins on the membrane of nano-sized extracellular vesicles (EVs) not only play crucial roles in cell-to-cell communication, but also are specific binding targets for EV detection, isolation and tracking. The low abundance of protein biomarkers on EV surface, the formation of clusters and the complex EV surface network impose significant challenges to the study of EVs. Employing bulky sized affinity ligands, such as antibodies, in the detection and characterization of these vesicles often result in reduced sensitivity of detection or poor quantification of proteins on the EV surface. By virtue of their small size and high specificity, Affibody molecules emerge as a potential alternative to their monoclonal antibody counterparts as robust affinity ligands in EV research. In this study, we present a theoretical framework on the superiority of anti-HER2 Affibodies over anti-HER2 antibodies in labeling and detecting HER2-positive EVs, followed by the demonstration of the advantages of HER2 Affibodies in accessing EV surface and the detection of EVs through multiple types of approaches including fluorescence intensity, colorimetry, and fluorescence polarization. HER2 Affibodies outperformed by 10-fold over three HER2 antibody clones in accessing HER2-positive EVs derived from different human cancer cell lines. Furthermore, HRP-Affibody molecules could detect EVs from cancer cells spiked into human serum with at least a 2-fold higher sensitivity compared with that of their antibody counterparts. In addition, in fluorescence polarization assays in which no separation of free from bound ligand is required, FITC-labeled HER2 Affibodies could sensitively detect HER2-positive EVs with a clinically relevant limit of detection, whilst HER2 antibodies failed to detect EVs in the same conditions. With the demonstrated superiority in accessing and detecting surface targets over bulky-sized antibodies in EVs, Affibodies may become the next-generation of affinity ligands in the precise characterization and quantification of molecular architecture on the surface of EVs. [ABSTRACT FROM AUTHOR]

Abstract Biosensing and detecting the rare circulating tumor cells (CTCs) in complex blood samples are a great challenge but necessary for cancer metastasis prevention. Here we show a novel highly-sensitive biosensing system for detecting CTCs in whole blood. The system is composed of Her2-coated immunomagnetic beads and an anti-EpCAM aptamer assembled pseudo-DNA nanocatenane (PDN) for dual targeting and separating CTCs, in conjunction with the rolling circle amplification (RCA) and molecular beacon (MB) system for CTCs signal amplification. The Her-2-coated beads separated CTCs from blood after their elution from a magnetic column. The unique PDN, which is a tailor-designed self-assembly of three circular DNAs that are inter-locked with independent and non-interfered templates for periodic RCA process, binds EpCAM-rich CTCs. In the presence of the RCA primer, phi29 DNA polymerase and MB, the system collaboratively generated the amplified fluorescent signals for highly-sensitive detection of CTCs. Through this system, we achieved the limit of detection less than 10 CTCs/mL blood, and quantified the number of CTCs in patient blood, which is proportional to the patient cancer status. Our technique is highly-sensitive, practicable and convenient enough for clinical detection of breast CTCs. Highlights • The detection of CTCs in peripheral blood are a great significance for tumor prevention. • The CTC detection system is composed of bead-based immunocapture, RCA and MB-based fluorescence detection. • The system reaches detection limit of 10 CTCs/mL blood, which is highly-sensitive, practicable and convenient enough for clinical detection of breast CTCs. [ABSTRACT FROM AUTHOR]

Regulation of tumor cell death is a fundamental mechanism for tumor treatment. However, most tumors are resistant to cell death. Triggering inflammatory cell death, pyroptosis, may provide a new view of enhancing tumor cell death. Here we report a new role of Ganoderma lucidum extract (GLE) in pyroptotic cell death. Treatment with GLE (50–200 μg/mL) significantly elevated reactive oxygen species (ROS) levels and caused pyroptotic cell death in breast cancer cells. Mechanistically, GLE activates caspase 3 and further cleaves the gasdermin E (GSDME) protein to form pores on the cell membrane, releasing massive amounts of inflammatory factors in breast cancer cells. We also showed that GLE enhanced antitumor immune responses by substantially increasing the subsets of natural killer (NK) and CD8+T cells in the peripheral immune system and tumor microenvironment. In addition, GLE destroys multiple steps of tumor metastasis, including adhesion, migration, invasion, colonization, and angiogenesis. Collectively, these results suggest that GLE provides a potential approach for breast cancer treatment, which may complement chemotherapy or immunotherapy for cancer metastasis. [Display omitted] • GLE initiates breast cancer cell pyroptosis via caspase3-mediated cleavage of GSDME protein. • GLE enhances anti-tumor immunity by unleashing NK and CD8+ T cells in local and system. • GLE blocks multi-steps of tumor metastasis including adhesion, migration, invasion, colonization and angiogenesis. [ABSTRACT FROM AUTHOR]