Coordination-Driven Self-Assembly of Metal Ion-Antisense Oligonucleotide Nanohybrids for Chronic Bacterial Infection Therapy.

Bacterial infection poses a significant challenge to wound healing and skin regeneration, leading to substantial economic burdens on patients and society. Therefore, it is crucial to promptly explore and develop effective methodologies for bacterial infections. Herein, we propose a novel approach for synthesizing nanostructures based on antisense oligonucleotides (ASOs) through the coordination-driven self-assembly of Zn2+ with ASO molecules. This approach aims to provide effective synergistic therapy for chronic wound infections caused by Staphylococcus aureus (S. aureus). The resulting hybrid nanoparticles successfully preserve the structural integrity and biological functionalities of ASOs, demonstrating excellent ASO encapsulation efficiency and bioaccessibility. In vitro antibacterial experiments reveal that Zn-ASO NPs exhibit antimicrobial properties against Escherichia coli, Staphylococcus aureus, and Bacillus subtilis. This antibacterial ability is attributed to the high concentration of metal zinc ions and the generation of high levels of reactive oxygen species. Additionally, the ftsZ-ASO effectively inhibits the expression of the ftsZ gene, further enhancing the antimicrobial effect. In vivo antibacterial assays demonstrate that the Zn-ASO NPs promote optimal skin wound healing and exhibit favorable biocompatibility against S. aureus infections, resulting in a residual infected area of less than 8%. This combined antibacterial strategy, which integrates antisense gene therapy and metal-coordination-directed self-assembly, not only achieves synergistic and augmented antibacterial outcomes but also expands the horizons of ASO coordination chemistry. Moreover, it addresses the gap in the antimicrobial application of metal-coordination ASO self-assembly, thereby advancing the field of ASO-based therapeutic approaches.

Targeting starvation therapy for diabetic bacterial infections with endogenous enzyme-triggered hyaluronan-modified nanozymes in the infection microenvironment.

The high-glycemic microenvironment of diabetic wounds promotes bacterial proliferation, leading to persistent infections and delayed wound healing. This poses a significant threat to human health, necessitating the development of new nanodrug visualization platforms. In this study, we designed and synthesized cascade nano-systems modified with targeted peptide and hyaluronic acid for diabetic infection therapy. The nano-systems were able to target the site of infection using LL-37, and in the microenvironment of wound infection, the hyaluronic acid shell of the nano-systems was degraded by endogenous hyaluronidase. This precise degradation released a cascade of nano-enzymes on the surface of the bacteria, effectively destroying their cytoskeleton. Additionally, the metals in the nano-enzymes provided a photo-thermal effect, accelerating wound healing. The cascade nano-visualization platform demonstrated excellent bactericidal efficacy in both in vitro antimicrobial assays and in vivo diabetic infection models. In conclusion, this nano-system employs multiple approaches including targeting, enzyme-catalyzed therapy, photothermal therapy, and chemodynamic therapy to kill bacteria and promote healing. The Ag@Pt-Au-LYZ/HA-LL-37 formulation shows great potential for the treatment of diabetic wounds.

Insights into the Overcoming EGFRDel19/T790M/C797S Mutation: A Perspective on the 2-Aryl-4-aminothienopyrimidine Backbone.

The epithelial growth factor receptor (EGFR) signaling pathway has been proposed to benefit non-small cell lung cancer (NSCLC) treatment. In this manuscript, we investigated the modification of 2-aryl-4-aminoquinazoline, the classical backbone of the fourth-generation EGFR inhibitors, in addition to obtaining a series of novel 2-aryl-4-aminothienopyrimidine derivatives (A1~A45), we also gained further understanding of the modification of this framework. Derivatives were tested for cytotoxicity against cancer cell lines (cervical cancer cell line Hela, lung cancer cell lines A549, H1975, and PC-9, Ba/F3-EGFRDel19/T790M/C797S cells, and human normal hepatocytes LO2) as well as for the derivative's inhibitory activity against EGFRWT, EGFRL858R/T790M, and EGFRDel19/T790M/C797S kinase inhibitory activities. The results showed that most of the target compounds showed moderate to excellent activity against one or more cancer cell lines. Among them, the antitumor activity (IC50) of the most promising A9 against A549 and H1975 cell lines was 0.77±0.08 µM, 6.90±0.83 µM, respectively. At concentration of 10 µM, A9 can be employed as the fourth-generation of EGFR inhibitors with the ability to overcome the C797S drug resistance since it can suppress EGFRDel19/T790M/C797S cells and kinase by 98.90 % and 85.88 %, respectively. Moreover, the tumor-bearing nude mice experiment further shows that A9 can significantly inhibit the growth of tumor in vivo, with the tumor inhibition rate (TIR) of 55.92 %, which was equivalent to the positive group. After that, from the result of HE staining experiment and blood biochemical analysis experiment, A9 show low toxicity and good safety, which is worthy of further research and development.

Rational design and synthesis of 2,4-dichloro-6-methyl pyrimidine derivatives as potential selective EGFRT790M/L858R inhibitors for the treatment of non-small cell lung cancer.

Many patients with non-small cell lung cancer (NSCLC) initially benefit from epidermal growth factor receptor (EGFR) targeted therapy. Unfortunately, varying degrees of resistance or side effects eventually develop. Overcoming and preventing the resistance and side effects of EGFR inhibitors has become a hot topic of research today. Based on the previous studies on AZD-9291, we designed and synthesized two series of 2,4-dichloro-6-methylpyrimidine derivatives, 19 compounds in total, as potential inhibitors of the EGFR kinase. The most promising compound, L-18, showed better inhibitory activity (81.9%) and selectivity against EGFRT790M/L858R kinase. In addition, L-18 showed strong antiproliferative activity against H1975 cells with an IC50 value of 0.65 ± 0.06 µM and no toxicity to normal cells (LO-2). L-18 was able to dose-dependently induce the apoptosis of H1975 cells and produced a cell-cycle-blocking effect, and it can also dose-dependently inhibit the migration and invasion of H1975 cells. L-18 also showed in vivo anticancer efficacy in H1975 cells xenograft mice. We also performed a series of in vivo and in vitro toxicological evaluations of compound L-18, which did not cause obvious injury in mice during administration. These results suggest that L-18 may be a promising drug candidate that warrants further investigation.

Novel bioactive 2-phenyl-4-aminopyrimidine derivatives as EGFRDel19/T790M/C797S inhibitors for the treatment of non-small cell lung cancer.

Overexpression of the epidermal growth factor receptor (EGFR) has been implicated in the development of non-small-cell lung cancer (NSCLC). Thus, EGFR is an effective drug target for the treatment of NSCLC, and developing fourth-generation EGFR inhibitors to overcome the resistance mediated by T790M/C797S mutations are currently under investigation. In this study, based on the binding model between Angew2017-7634-1 and EGFRT790M/C797S , several series of 2-phenyl-4-aminopyrimidine derivatives were designed and synthesized. The bioactivity of these compounds was evaluated and it is suggested that compound A23 could effectively inhibit the proliferation of Ba/F3-EGFRDel19/T790M/C797S and H1975-EGFRL858R/T790M cells, with an IC50 of 0.22 ± 0.07 and 0.52 ± 0.03 µM, respectively. Meanwhile, the kinase activity of A23 against EGFRL858R/T790M and EGFRDel19/T790M/C797S was also evaluated, with an IC50 of 0.33 and 0.133 µM, respectively. Moreover, compound A23 was further evaluated in the H1975 xenograft models with significant in vivo tumor growth inhibitions of 25.5%, which means that A23 could effectively inhibit the growth of tumor cells and promote the death of tumor cells. As a result, A23 could be identified as a novel potential EGFRDel19/T790M/C797S inhibitor.

Novel quinazoline-based dual EGFR/c-Met inhibitors overcoming drug resistance for the treatment of NSCLC: Design, synthesis and anti-tumor activity.

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs) have demonstrated the ability to impede tumor cell proliferation by suppressing EGFR expression. Nonetheless, patients undergoing treatment may acquire resistance, which may occur through an EGFR-dependent (such as T790M mutation) or an EGFR-independent (such as c-Met amplification) manner. Therefore, developing dual-target inhibitors might present a potential avenue for addressing treatment-acquired resistance in patients. Herein, we designed, synthesized, and screened several novel 4-phenoxyquinazoline derivatives, aiming to identify a potent dual EGFR/c-Met inhibitor for the treatment of NSCLC, among which H-22 emerged as the most promising candidate exhibiting significant antitumor properties. Moreover, we assessed the in vitro inhibitory effect of H-22 on EGFR kinase and c-Met kinase in five cancer cell lines. In addition, a series of functional experiments (cell cycle, apoptosis assays, in vitro/in vivo animal model, etc.) were conducted to further investigate the anti-tumor mechanisms of H-22. The present study revealed that H-22 exhibited strong antitumor activity both in vitro and in vivo. Interestingly, H-22 exhibited anti-proliferative activity (2.27-3.35 µM) similar to Afatinib against all five cancer cells, with inhibitory functions against EGFRWT, EGFRL858R/T790M, and c-Met kinases at a concentration of 64.8, 305.4 and 137.4 nM, respectively. Cell cycle analysis indicated that the antiproliferative activity of H-22 was associated with its ability to cause G2/M arrest. Furthermore, in vivo data showed that H-22 could inhibit tumor growth in our xenograft models and induce apoptosis. Collectively, our findings uncovered that H-22 is a novel dual EGFR and c-Met inhibitor and a prospective anti-tumor therapeutic drug.

Photothermally Enhanced Cascaded Nanozyme-Functionalized Black Phosphorus Nanosheets for Targeted Treatment of Infected Diabetic Wounds.

Due to the limitations of H2 O2 under physiological conditions and defective activity, nanozyme-catalyzed therapy for infected diabetic wound healing is still a huge challenge. Here, this work designs a novel multifunctional hybrid glucose oxidase (GOx)-CeO2 @black phosphorus (BP)/Apt nanosheet that features GOx and CeO2 dual enzyme loading with photothermal enhancement effect and targeting ability for the treatment of infected wounds in type II diabetic mice. Combined with the photothermal properties of the BP nanosheets, the cascade nanozyme effect of GOx and CeO2 is extremely enhanced. The synergistic effect of peroxidase activity and photothermal therapy with targeting aptamer allows for overcoming the catalytic defects of nanozyme and significantly improving in vitro bacterial inhibition rate with 99.9% and 97.8% for Staphylococcus aureus and Escherichia coli, respectively, as well as enhancing in vivo antibacterial performance with the lowest wound remained (0.05%), reduction of infiltration inflammatory cells, and excellent biocompatibility. Overall, this work builds a nanodelivery system with a powerful therapeutic approach, incorporating self-supplying H2 O2 synergistic photothermal and real-time wound monitoring effect, which holds profound potential as a clinical treatment for infected diabetic wounds.

Discovery of novel 4-arylamino-quinazoline derivatives as EGFRL858R/T790M inhibitors with the potential to inhibit the non-small cell lung cancers.

Three series of quinazoline derivatives (7a-j, 8a-o, 9a-l) were designed and synthesized as EGFRL858R/T790M inhibitors. Series 7a-j and 8a-o are urea and thiourea derivatives while category 9a-l contain the Michael receptor active warhead. Most of the compounds exhibited excellent anti-proliferative activity in vitro against several cancer cell lines, including non-small cell lung cancer (NSCLC) cell lines A549 and H1975, among which 14 compounds had strong antiproliferative activity against A549 and H1975 cancer cells. What's more, they also showed moderate to excellent kinase inhibitory activity against EGFRWT and EGFRL858R/T790M. 8o exhibited the best kinase inhibitory activity with IC50 values of 0.8, 2.7 nM against EGFRWT and EGFRL858R/T790M, respectively. Moreover, AO single staining and Annexin V-FITC/PI staining results also indicated that both 8o and 9b significantly induced apoptosis in A549 cells. 8o arrested the cell cycle at S phase and 9b arrested the cell cycle at G1 phase.

Design, Synthesis, and Biological Evaluation of [1,2,4]triazolo[4,3-a] Pyrazine Derivatives as Novel Dual c-Met/VEGFR-2 Inhibitors.

In this study, we designed and synthesized a series of novel [1,2,4]triazolo [4,3-a]pyrazine derivatives, and evaluated them for their inhibitory activities toward c-Met/VEGFR-2 kinases and antiproliferative activities against tested three cell lines in vitro. Most of the compounds showed satisfactory activity compared with lead compound foretinib. Among them, the most promising compound 17l exhibited excellent antiproliferative activities against A549, MCF-7, and Hela cancer cell lines with IC50 values of 0.98 ± 0.08, 1.05 ± 0.17, and 1.28 ± 0.25 µM, respectively, as well as excellent kinase inhibitory activities (c-Met IC50 = 26.00 nM and VEGFR-2 IC50 = 2.6 µM). Moreover, compound 17l inhibited the growth of A549 cells in G0/G1 phase in a dose-dependent manner, and induced the late apoptosis of A549 cells. Its intervention on intracellular c-Met signaling of A549 was verified by the result of Western blot. Fluorescence quantitative PCR showed that compound 17l inhibited the growth of A549 cells by inhibiting the expression of c-Met and VEGFR-2, and its hemolytic toxicity was low. Molecular docking and molecular dynamics simulation indicated that compound 17l could bind to c-Met and VEGFR-2 protein, which was similar to that of foretinib.

An updated patent review of small-molecule ROS1 kinase inhibitors (2015-2021).

INTRODUCTION: C-ros oncogene 1 (ROS1) is the sole member of the ROS1 receptor tyrosine kinase (ROS1-RTK) family, which is involved in the formation of non-small cell lung cancer (NSCLC), gastric adenocarcinoma, colorectal cancer, and other malignant tumors. At present, only crizotinib was approved for the treatment of advanced ROS1-positive NSCLC, and there have been reports of ROS1 mutations resulting in drug resistance. Consequently, it is necessary to develop new generations of inhibitors to overcome the existing problems. AREAS COVERED: This review summarizes the inhibitors with ROS1 inhibitory activity which are undergoing clinical trials and recent advances in patented ROS1 small molecular inhibitors from 2015 to 2021. EXPERT OPINION: ROS1 rearrangements have been found in approximately 1%-2% of patients with NSCLC. Since the approval of crizotinib as multi-targeted ALK/MET/ROS1 kinase inhibitor for ALK-mutated NSCLC therapy, the researchers are focusing on ROS1-mutated tumors, especially NSCLC. However, drug-resistant mutations have already been found in clinical application. Therefore, it is still urgent to develop new generation of ROS1 inhibitors.

Biomineralized Cascade Enzyme-Encapsulated ZIF-8 Nanoparticles Combined with Antisense Oligonucleotides for Drug-Resistant Bacteria Treatment.

The unrestrained use of antibiotics accelerates the development of drug-resistant bacteria and leads to an increasing threat to human health. Therefore, there is an urgent need to explore novel and effective strategies for the treatment of bacterial infections. Herein, zeolite imidazole framework-8 (ZIF-8) material was utilized to construct biomineralized nanomaterial (GOx&HRP@ZIF-8/ASO) by encapsulating biological cascade enzymes and combining with antisense oligonucleotides (ASOs), which achieved effective and synergistic antidrug-resistant bacteria therapy. Various in vitro assays confirmed that GOx&HRP@ZIF-8/ASO exhibited excellent antibacterial properties against Escherichia coli, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA) during catalysis of glucose (Glu), especially the minimum inhibitory concentration (MIC) against MRSA was only 16 µg/mL. Compared with simple ZIF-8 (32.85%) and ftsZ ASO (58.65%), GOx&HRP@ZIF-8/ASO+Glu exhibited superb biofilm destruction ability, and the bacteria removal efficiency of the MRSA biofilm could be as high as 88.2%, indicating that the reactive oxygen species (ROS) produced by the cascade enzyme reaction imparted the main synergistic antibacterial capability, and simultaneously, ftsZ ASO significantly enhanced the antibacterial effect by inhibiting the expression of the ftsZ gene. In vivo anti-infection treatment experiments revealed that GOx&HRP@ZIF-8/ASO exhibited the best wound repairing performance and excellent biocompatibility in the presence of Glu. These findings suggested that GOx&HRP@ZIF-8/ASO has favorably realized high-efficiency treatment of MRSA infection and filled the gap in the antibacterial application of biological enzymes.

An updated patent review of small-molecule c-Met kinase inhibitors (2018-present).

INTRODUCTION: c-Met tyrosine kinase receptor is a high-affinity ligand of hepatocyte growth factor (HGF). c-Met is widely expressed in a variety of normal human tissues, but shows abnormally high expression, amplification or mutation in tumour tissues such as lung, gastric and breast cancers. Therefore, the use of c-Met as a target can achieve the inhibition of a series of abnormal physiological processes such as tumourigenesis, development and metastasis. A number of small molecule tyrosine kinase inhibitors targeting c-Met have been successfully marketed. AREAS COVERED: This article reviews recent advances in patented c-Met small molecule inhibitors and their inhibitory activity against various cancer cells from 2018 to date. EXPERT OPINION: To date, small molecule inhibitors targeting c-Met have demonstrated impressive therapeutic efficacy in the clinical setting. Most recent patents have focused on addressing the direction of c-Met amplification and overexpression. Despite the great success in the development of selective c-Met inhibitors, the effects of bypass secretion and mutagenesis have led to a need for new c-Met small molecule inhibitors that are safe, efficient, selective and less toxic with novel structures and effective against other targets.

Design, Synthesis, and Antitumor Activity of Olmutinib Derivatives Containing Acrylamide Moiety.

Two series of olmutinib derivatives containing an acrylamide moiety were designed and synthesized, and their IC50 values against cancer cell lines (A549, H1975, NCI-H460, LO2, and MCF-7) were evaluated. Most of the compounds exhibited moderate cytotoxic activity against the five cancer cell lines. The most promising compound, H10, showed not only excellent activity against EGFR kinase but also positive biological activity against PI3K kinase. The structure-activity relationship (SAR) suggested that the introduction of dimethylamine scaffolds with smaller spatial structures was more favorable for antitumor activity. Additionally, the substitution of different acrylamide side chains had different effects on the activity of compounds. Generally, compounds H7 and H10 were confirmed as promising antitumor agents.

Design, synthesis and evaluation of anti-proliferative activity of 2-aryl-4-aminoquinazoline derivatives as EGFR inhibitors.

A class of 2-aryl-4-aminoquinazoline derivatives (7a-7j, 8a-8h, 9a-9h and 10a-10k) were designed, synthesized and evaluated as EGFR inhibitors. The anti-proliferative activity of compounds in vitro showed that compound 9e was considered to be a promising derivative. Compared with the lead compound Angew2017-7634-1, 9e exhibited excellent inhibitory activity against A549, NCI-H460 and H1975 cell lines, with IC50 values of 14.33 ± 1.16 µM, 17.81 ± 1.25 µM and 13.41 ± 1.14 µM, respectively. Moreover, 9e could effectively inhibit against Ba/F3-EGFRDel19/T790M/C797S cell lines. In the kinase experiment, the most promising compound 9e exhibited excellent enzymatic inhibitory activity and selectivity for EGFRL858R/T790M, with an IC50 value of 0.74 µM. Further activity studies showed that 9e could not only induce remarkable cell-apoptosis of A549, but also block A549 cell lines in S-phase in a concentration-dependent manner. Furthermore, molecular docking study revealed the binding mode of 9e. All in all, we analyzed the structure-activity relationship of the target compounds, and explored their mechanism of action.

Biomineralized metal-organic framework nanoparticles enable a primer exchange reaction-based DNA machine to work in living cells for imaging and gene therapy.

Sensitive tumor imaging and precise tumor therapy play critical roles in the cancer combat. Herein, we build a DNA machine based on a primer exchange reaction (PER) for mRNA imaging and gene therapy. By using zeolitic imidazolate framework-8 nanoparticles (ZIF-8 NPs) to co-deliver the components including a primer, hairpin and strand displacing polymerase to the living cells, the PER-based DNA machine can be initiated by intracellular survivin mRNA and continuously produce Bcl-2 antisense DNA (ASD), which enables the DNA machine not only to image survivin mRNA but also to implement gene therapy. The results demonstrate that ZIF-8 NPs can protect the polymerases and nucleic acid probes from protease attack and nuclease degradation. After internalization, pH-responsive ZIF-8 NPs can efficiently release cargos from endo-lysosomes due to the protonation effect. The intracellular PER-based DNA machine has been demonstrated to be able to sensitively image survivin mRNA expression levels and selectively kill the cancer cells and has no effect on the normal cells. The PER-based DNA machine may provide a promising platform for early stage tumor diagnosis and more precise tumor therapy.

An intelligent nanodevice based on the synergistic effect of telomerase-triggered photodynamic therapy and gene-silencing for precise cancer cell therapy.

The development of intelligent and precise cancer therapy systems that enable accurate diagnosis and specific elimination of cancer cells while protecting normal cells to improve the safety and effectiveness of the treatment is still a challenge. Herein, we report a novel activatable nanodevice for precise cancer therapy. The nanodevice is constructed by adsorbing a DNA duplex probe onto MnO2 nanosheets. After cellular uptake, the DNA duplex probe undergoes telomerase-triggered conformation switching, resulting in a Ce6 "turn-on" signal for the identification of cancer cells. Furthermore, Deoxyribozyme (DNAzyme) is activated to catalyse the cleavage of survivin mRNA, actualizing a precise synergistic therapy in cancer cells involving photodynamic therapy and gene-silencing. The MnO2 nanosheets provide Mn2+ for the DNAzyme and relieve hypoxia to improve the efficiency of the photodynamic therapy. Live cell studies reveal that this nanodevice can diagnose cancer cells and specifically eliminate them without harming normal cells, so making the treatment safer and more effective. The developed DNA-MnO2 nanodevice provides a valuable and general platform for precise cancer therapy.

Improving resolving ability of expansion microscopy by varying crosslinker concentration.

Here, we systematically investigated the performance of expansion microscopy (ExM) with different crosslinker concentrations. We modified ExM with 0.06% N,N'-methylenebisacrylamide (MBAA) (termed 0.06%-MBAA ExM), increased the expansion factor to 5.7 and achieved a lateral resolution of ∼50 nm with a common confocal microscope.

A photocontrolled and self-powered bipedal DNA walking machine for intracellular microRNA imaging.

In this work, we report a photocontrolled and self-powered DNA walking machine with bipedal DNAzyme walkers for intracellular microRNA imaging.

Aptamer-Functionalized DNA Origami for Targeted Codelivery of Antisense Oligonucleotides and Doxorubicin to Enhance Therapy in Drug-Resistant Cancer Cells.

Drug resistance is a major obstacle to the efficient therapy of drug-resistant cancer. To overcome this problem, we constructed a multifunctional DNA origami-based nanocarrier for codelivery of a chemotherapeutic drug (doxorubicin, Dox) and two different antisense oligonucleotides (ASOs; B-cell lymphoma 2 (Bcl2) and P-glycoprotein (P-gp)) into drug-resistant cancer cells for enhanced therapy. To increase the targeting ability of origami, staple strands with 5'-end extended MUC1 sequences were used in the preparation of aptamer-functionalized origami carrying ASOs (Apt-origami-ASO). Dox-loaded Apt-origami-ASO (Apt-Dox-origami-ASO) was prepared by electrostatic adsorption of Dox in origami. Atomic force microscopy (AFM) images demonstrated the successful preparation of Apt-origami-ASO. In vitro studies showed that the Apt-Dox-origami-ASO (Apt-DOA) could controllably release Dox in pH 5.0 phosphate-buffered saline (PBS) buffer and release ASOs in response to glutathione. Further experiments revealed that the origami could protect ASOs against nuclease degradation in 10% FBS. Confocal imaging showed that the Apt-DOA nanocarrier could efficiently enter the Hela/adriamycin (ADR) cells and escape from lysosomes for codelivery of Dox and ASOs into the cytoplasm. The quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and western blot assays testified the efficient silencing of Bcl2 and P-gp mRNA and downregulation of the corresponding protein expressions by Apt-DOA in Hela/ADR cells. Moreover, with the synergetic effect by codelivery of multi-ASOs and Dox, the anticancer assay showed that Apt-DOA could circumvent multidrug resistance and significantly enhance cancer therapy in Hela/ADR and MCF-7/ADR cells. Hence, this multifunctional origami-based codelivery nanocarrier presents a new strategy for efficient therapy of drug-resistant cancer.

A spatial-confinement hairpin cascade reaction-based DNA tetrahedral amplifier for mRNA imaging in live cells.

The three-dimensional (3D) DNA nanostructure has been got much attention due to its excellent biocompatibility, enhanced structural stability, highly programmable and perfect cell-delivery performance. Here, a novel 3D DNA tetrahedron amplifier (DTA) has been developed for rapid and efficient mRNA imaging in living cells using target catalyzing spatial-confinement hairpin DNA assembly cascade reaction inside the DNA nanostructure. The DTA was constructed by assembling a DNA tetrahedron with four DNA strands at first, and then by assembling two metastable DNA hairpins H1 (Cy5) and H2 (Cy3) at specific locations of the DNA tetrahedron. In the presence of target mRNA, the catalyzed hairpin assembly (CHA) reaction on the DTA could be triggered and a H1-H2 duplexes nanostructure could be formed, which would obtain a significant fluorescence resonance energy transfer (FRET) signal, and release the target mRNA could trigger next H1-H2 duplexes formation. Due to the 3D DNA tetrahedral spatial-confinement effect, the circular reaction of DTA could achieve rapid and efficient amplification detection of target mRNA in living cells. Moreover, the DTA show excellent structural stability and non-cytotoxicity. This strategy presents a versatile method for the ultrasensitive detection of biomarkers in living system and gains a deeper development of the DNA nanostructures in biomedical functions.