RESUMO
Unlike acoustic metasurfaces that rely solely on phase gradients, acoustic metagratings (AMs) operate based on both phase gradients and grating diffraction, thus further extending the generalized Snell's law (GSL). In particular, AMs can achieve reversal of refraction and reflection based on the parity of the number of wave propagations inside the AMs. So far, discussions of this GSL extension have largely been applied to one-dimensional periodic AMs, while the designs of two-dimensional (2D) periodic AMs and their performance in three-dimensional (3D) space have been quite limited. Here, we study the GSL extension in 3D space and experimentally demonstrate a series of functional 2D periodic AMs. The designed AMs can achieve sound refraction/reflection under any incidence angle in 3D space, without restrictions to certain critical ranges; adjusting incident angles only enables the reversal of refraction and reflection. Additionally, we demonstrate two types of dual-layer sound lenses based on two AMs, whose reversal of refraction and reflection can be realized by simply attaching or separating the two AMs. Our work paves the way to complex 3D wavefront manipulation of AMs, which may find potential use in practical acoustic devices.
RESUMO
RNA editing is a crucial post-transcriptional process that influences gene expression and increases the diversity of the proteome as a result of amino acid substitution. Recently, the APOBEC3 family has emerged as a significant player in this mechanism, with APOBEC3A (A3A) having prominent roles in base editing during immune and stress responses. APOBEC3B (A3B), another family member, has gained attention for its potential role in generating genomic DNA mutations in breast cancer. In this study, we coupled an inducible expression cell model with a novel methodology for identifying differential variants in RNA (DVRs) to map A3B-mediated RNA editing sites in a breast cancer cell model. Our findings indicate that A3B engages in selective RNA editing including targeting NEAT1 and MALAT1 long non-coding RNAs that are often highly expressed in tumour cells. Notably, the binding of these RNAs sequesters A3B and suppresses global A3B activity against RNA and DNA. Release of A3B from NEAT1/MALAT1 resulted in increased A3B activity at the expense of A3A activity suggesting a regulatory feedback loop between the two family members. This research substantially advances our understanding of A3B's role in RNA editing, its mechanistic underpinnings, and its potential relevance in the pathogenesis of breast cancer.
RESUMO
Human telomerase reverse transcriptase (hTERT) may have noncanonical functions in transcriptional regulation and metabolic reprogramming in cancer cells, but it is a challenging target. We thus developed small-molecule ligands targeting hTERT promoter G-quadruplex DNA structures (hTERT G4) to downregulate hTERT expression. Ligand 5 showed high affinity toward hTERT G4 (Kd = 1.1 µM) and potent activity against triple-negative breast cancer cells (MDA-MB-231, IC50 = 1 µM). In cell-based assays, 5 not only exerts markedly inhibitory activity on classical telomere functions including decreased telomerase activity, shortened telomere length, and cellular senescence but also induces DNA damage, acute cellular senescence, and apoptosis. This study reveals that hTERT G4-targeting ligand may cause mitochondrial dysfunction, disrupt iron metabolism and activate ferroptosis in cancer cells. The in vivo antitumor efficacy of 5 was also evaluated in an MDA-MB-231 xenograft mouse model and approximately 78.7% tumor weight reduction was achieved. No observable toxicity against the major organs was observed.
Assuntos
Antineoplásicos , Regulação para Baixo , Quadruplex G , Regiões Promotoras Genéticas , Telomerase , Neoplasias de Mama Triplo Negativas , Telomerase/antagonistas & inibidores , Telomerase/metabolismo , Humanos , Quadruplex G/efeitos dos fármacos , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/patologia , Animais , Ligantes , Feminino , Regulação para Baixo/efeitos dos fármacos , Camundongos , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/uso terapêutico , Linhagem Celular Tumoral , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia , Apoptose/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto , Camundongos Nus , Senescência Celular/efeitos dos fármacos , Camundongos Endogâmicos BALB CRESUMO
Gastrointestinal cancer is among the most common cancers worldwide. Immune checkpoint inhibitor-based cancer immunotherapy has become an innovative approach in cancer treatment; however, its efficacy in gastrointestinal cancer is limited by the absence of infiltration of immune cells within the tumor microenvironment. Therefore, it is therefore urgent to develop a novel therapeutic drug to enhance immunotherapy. In this study, we describe a previously unreported potentiating effect of Icariside I (ICA I, GH01), the main bioactive compound isolated from the Epimedium species, on anti-tumor immune responses. Mechanistically, molecular docking and SPR assay result show that ICA I binding with TRPV4. ICA I induced intracellular Ca2+ increasing and mitochondrial DNA release by targeting TRPV4, which triggered cytosolic ox-mitoDNA release. Importantly, these intracellular ox-mitoDNA fragments were taken up by immune cells in the tumor microenvironment, which amplified the immune response. Moreover, our study shows the remarkable efficacy of sequential administration of ICA I and anti-α-PD-1 mAb in advanced tumors and provides a strong scientific rationale for recommending such a combination therapy for clinical trials. ICA I enhanced the anti-tumor effects with PD-1 inhibitors by regulating the TRPV4/Ca2+/Ox-mitoDNA/cGAS/STING axis. We expect that these findings will be translated into clinical therapies, which will benefit more patients with cancer in the near future.
Assuntos
Flavonoides , Neoplasias Gastrointestinais , Imunoterapia , Proteínas de Membrana , Canais de Cátion TRPV , Humanos , Canais de Cátion TRPV/metabolismo , Canais de Cátion TRPV/antagonistas & inibidores , Proteínas de Membrana/metabolismo , Animais , Imunoterapia/métodos , Linhagem Celular Tumoral , Neoplasias Gastrointestinais/tratamento farmacológico , Neoplasias Gastrointestinais/imunologia , Neoplasias Gastrointestinais/patologia , Flavonoides/farmacologia , Microambiente Tumoral/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Camundongos , Sinergismo Farmacológico , Inibidores de Checkpoint Imunológico/farmacologia , Feminino , Camundongos Endogâmicos BALB C , DNA Mitocondrial , Simulação de Acoplamento MolecularRESUMO
Millirobots must have low cost, efficient locomotion, and the ability to track target trajectories precisely if they are to be widely deployed. With current materials and fabrication methods, achieving all of these features in one millirobot remains difficult. We develop a series of graphene-based helical millirobots by introducing asymmetric light pattern distortion to a laser-induced polymer-to-graphene conversion process; this distortion resulted in the spontaneous twisting and peeling off of graphene sheets from the polymer substrate. The lightweight nature of graphene in combine with the laser-induced porous microstructure provides a millirobot scaffold with a low density and high surface hydrophobicity. Magnetically driven nickel-coated graphene-based helical millirobots with rapid locomotion, excellent trajectory tracking, and precise drug delivery ability were fabricated from the scaffold. Importantly, such high-performance millirobots are fabricated at a speed of 77 scaffolds per second, demonstrating their potential in high-throughput and large-scale production. By using drug delivery for gastric cancer treatment as an example, we demonstrate the advantages of the graphene-based helical millirobots in terms of their long-distance locomotion and drug transport in a physiological environment. This study demonstrates the potential of the graphene-based helical millirobots to meet performance, versatility, scalability, and cost-effectiveness requirements simultaneously.
RESUMO
Metasurface holograms represent a common category of metasurface devices that utilize in-plane phase gradients to shape wavefronts, forming holographic images through the application of the generalized Snell's law (GSL). While conventional metasurfaces focus solely on phase gradients, metagratings, which incorporate higher-order wave diffraction, further expand the GSL's generality. Recent advances in certain acoustic metagratings demonstrate an updated GSL extension capable of reversing anomalous transmission and reflection, whose reversal is characterized by the parity of the number of wave propagation trips through the metagrating. However, the current extension of GSL remains limited to 1D metagratings, unable to access 2D holographic images in 3D spaces. Here, the GSL extension to 2D metagratings for manipulating waves within 3D spaces is investigated. Through this analysis, a series of acoustic metagrating holograms is experimentally demonstrated. These holographic images exhibit the unique ability to switch between transmission and reflection types independently. This study introduces an additional dimension to modern holography design and metasurface wavefront manipulation.
RESUMO
Mitochondria are important drug targets for anticancer and other disease therapies. Certain human mitochondrial DNA sequences capable of forming G-quadruplex structures (G4s) are emerging drug targets of small molecules. Despite some mitochondria-selective ligands being reported for drug delivery against cancers, the ligand design is mostly limited to the triphenylphosphonium scaffold. The ligand designed with lipophilic small-sized scaffolds bearing multipositive charges targeting the unique feature of high mitochondrial membrane potential (MMP) is lacking and most mitochondria-selective ligands are not G4-targeting. Herein, we report a new small-sized dicationic lipophilic ligand to target MMP and mitochondrial DNA G4s to enhance drug delivery for anticancer. The ligand showed marked alteration of mitochondrial gene expression and substantial induction of ROS production, mitochondrial dysfunction, DNA damage, cellular senescence, and apoptosis. The ligand also exhibited high anticancer activity against HCT116 cancer cells (IC50, 3.4 µM) and high antitumor efficacy in the HCT116 tumor xenograft mouse model (â¼70% tumor weight reduction).
Assuntos
Antineoplásicos , Neoplasias Colorretais , Quadruplex G , Mitocôndrias , Humanos , Quadruplex G/efeitos dos fármacos , Ligantes , Animais , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/síntese química , Antineoplásicos/uso terapêutico , Camundongos , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/patologia , Neoplasias Colorretais/metabolismo , Apoptose/efeitos dos fármacos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Camundongos Nus , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia , Bibliotecas de Moléculas Pequenas/síntese química , Ensaios Antitumorais Modelo de Xenoenxerto , Células HCT116 , DNA Mitocondrial/metabolismoRESUMO
Glioblastoma (GBM), deep in the brain, is more challenging to diagnose and treat than other tumors. Such challenges have blocked the development of high-impact therapeutic approaches that combine reliable diagnosis with targeted therapy. Herein, effective cyanine dyes (IRLy) with the near-infrared two region (NIR-II) adsorption and aggregation-induced emission (AIE) have been developed via an "extended conjugation & molecular rotor" strategy for multimodal imaging and phototherapy of deep orthotopic GBM. IRLy was synthesized successfully through a rational molecular rotor modification with stronger penetration, higher signal-to-noise ratio, and a high photothermal conversion efficiency (PCE) up to â¼60%, which can achieve efficient NIR-II photo-response. The multifunctional nanoparticles (Tf-IRLy NPs) were further fabricated to cross the blood-brain barrier (BBB) introducing transferrin (Tf) as a targeting ligand. Tf-IRLy NPs showed high biosafety and good tumor enrichment for GBM in vitro and in vivo, and thus enabled accurate, efficient, and less invasive NIR-II multimodal imaging and photothermal therapy. This versatile Tf-IRLy nanosystem can provide a reference for the efficient, precise and low-invasive multi-synergistic brain targeted photo-theranostics. In addition, the "extended conjugation & molecular rotor" strategy can be used to guide the design of other photothermal agents.
Assuntos
Glioblastoma , Nanopartículas , Neoplasias , Humanos , Glioblastoma/diagnóstico por imagem , Glioblastoma/terapia , Fototerapia/métodos , Encéfalo , Barreira Hematoencefálica , Corantes , Nanomedicina Teranóstica/métodos , Nanopartículas/uso terapêutico , Linhagem Celular TumoralRESUMO
rRNAs are prevalent in living organisms. They are produced in nucleolus and mitochondria and play essential cellular functions. In addition to the primary biofunction in protein synthesis, rRNAs have been recognized as the emerging signaling molecule and drug target for studies on nucleolus morphology, mitochondrial autophagy, and tumor cell malignancy. Currently, only a few rRNA-selective probes have been developed, and most of them encounter the drawbacks of low water solubility, poor nuclear membrane permeability, short emission wavelength, low stability against photobleaching, and high cytotoxicity. These unfavorable properties of rRNA probes limit their potential applications. In the present study, we reported a new rRNA-selective and near-infrared fluorescent turn-on probe, 4MPS-TO, capable of tracking rRNA in live human cancer cells. The real-time monitoring performance in nucleolus morphology and mitochondrial autophagy is demonstrated in HeLa cells. The probe shows great application potential for being used as a rRNA-selective, sensitive, and photostable imaging tool in chemical biology study and drug screening.
Assuntos
Mitofagia , Neoplasias , Humanos , Células HeLa , Corantes Fluorescentes/química , Imagem Óptica/métodos , AutofagiaRESUMO
Thyroid ultrasound is a widely used diagnostic technique for thyroid nodules in clinical practice. However, due to the characteristics of ultrasonic imaging, such as low image contrast, high noise levels, and heterogeneous features, detecting and identifying nodules remains challenging. In addition, high-quality labeled medical imaging datasets are rare, and thyroid ultrasound images are no exception, posing a significant challenge for machine learning applications in medical image analysis. In this study, we propose a Dual-branch Attention Learning (DBAL) convolutional neural network framework to enhance thyroid nodule detection by capturing contextual information. Leveraging jigsaw puzzles as a pretext task during network training, we improve the network's generalization ability with limited data. Our framework effectively captures intrinsic features in a global-to-local manner. Experimental results involve self-supervised pre-training on unlabeled ultrasound images and fine-tuning using 1216 clinical ultrasound images from a collaborating hospital. DBAL achieves accurate discrimination of thyroid nodules, with a 88.5% correct diagnosis rate for malignant and benign nodules and a 93.7% area under the ROC curve. This novel approach demonstrates promising potential in clinical applications for its accuracy and efficiency.
RESUMO
Background: Drug-target interaction (DTI) is a vital drug design strategy that plays a significant role in many processes of complex diseases and cellular events. In the face of challenges such as extensive protein data and experimental costs, it is suggested to apply bioinformatics approaches to exploit potential interactions to design new targeted medications. Different data and interaction types bring difficulties to study involving incompatible and heterology formats. The analysis of drug-target interactions in a comprehensive and unified model is a significant challenge. Method: Here, we propose a general method for predicting interactions between small-molecule drugs and protein targets, Large-scale Drug target Screening Convolutional Neural Network (LDS-CNN), which used unified encoding to achieve the calculation of the different data formats in an integrated model to realize feature abstraction and potential object prediction. Result: On 898,412 interaction data involving 1683 small-molecule compounds and 14,350 human proteins from 8.8 billion records, the proposed method achieved an area under the curve (AUC) of 0.96, an area under the precision-recall curve (AUPRC) of 0.95, and an accuracy of 90.13%. The experimental results illustrated that the proposed method attained high accuracy on the test set, indicating its high predictive ability in drug-target interaction prediction. LDS-CNN is effective for the prediction of large-scale datasets and datasets composed of data with different formats. Conclusion: In this study, we propose a DTI prediction method to solve the problems of unified encoding of large-scale data in multiple formats. It provides a feasible way to efficiently abstract the features among different types of drug-related data, thus reducing experimental costs and time consumption. The proposed method can be used to identify potential drug targets and candidates for the treatment of complex diseases. This work provides a reference for DTI to process large-scale data and different formats with deep learning methods and provides certain suggestions for future research.
RESUMO
BACKGROUND AND OBJECTIVE: Patients with rheumatoid arthritis (RA) are more susceptible to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) than healthy population, but there is still no therapeutic strategy available for RA patients with corona virus disease 2019 (COVID-19). Guizhi-Shaoyao-Zhimu decoction (GSZD), Chinese ancient experience decoction, has a significant effect on the treatment of Rheumatism and gout. To prevent RA patients with mild-to-moderate COVID-19 from developing into severe COVID-19, this study explored the potential possibility and mechanism of GSZD in the treatment of this population. METHODS: In this study, we used bioinformatic approaches to explore common pharmacological targets and signaling pathways between RA and mild-to-moderate COVID-19, and to assess the potential mechanisms of in the treatment of patients with both diseases. Beside, molecular docking was used to explore the molecular interactions between GSZD and SARS-CoV-2 related proteins. RESULTS: Results showed that 1183 common targets were found in mild-to-moderate COVID-19 and RA, of which TNF was the most critical target. The crosstalk signaling pathways of the two diseases focused on innate immunity and T cells pathways. In addition, GSZD intervened in RA and mild-to-moderate COVID-19 mainly by regulating inflammation-related signaling pathways and oxidative stress. Twenty hub compounds in GSZD exhibited good binding potential to SARS-CoV-2 spike (S) protein, 3C-like protease (3CLpro), RNA-dependent RNA polymerase (RdRp), papain-like protease (PLpro) and human angiotensin-converting enzyme 2 (ACE2), thereby intervening in viral infection, replication and transcription. CONCLUSIONS: This finding provides a therapeutic option for RA patients against mild-to-moderate COVID-19, but further clinical validation is still needed.
Assuntos
Artrite Reumatoide , COVID-19 , Humanos , Simulação de Acoplamento Molecular , SARS-CoV-2 , Artrite Reumatoide/tratamento farmacológico , Biologia ComputacionalRESUMO
The development of site-specific, target-selective and biocompatible small molecule ligands as a fluorescent tool for real-time study of cellular functions of RNA G-quadruplexes (G4s), which are associated with human cancers, is of significance in cancer biology. We report a fluorescent ligand that is a cytoplasm-specific and RNA G4-selective fluorescent biosensor in live HeLa cells. The inâ vitro results show that the ligand is highly selective targeting RNA G4s including VEGF, NRAS, BCL2 and TERRA. These G4s are recognized as human cancer hallmarks. Moreover, intracellular competition studies with BRACO19 and PDS, and the colocalization study with G4-specific antibody (BG4) in HeLa cells may support that the ligand selectively binds to G4s in cellulo. Furthermore, the ligand was demonstrated for the first time in the visualization and monitoring of dynamic resolving process of RNA G4s by the overexpressed RFP-tagged DHX36 helicase in live HeLa cells.
Assuntos
Quadruplex G , Neoplasias , Humanos , Células HeLa , Ligantes , RNA/metabolismo , Citoplasma/metabolismoRESUMO
Photosensitizers play a key role in bioimaging and photodynamic therapy (PDT) of cancer. However, conventional photosensitizers usually do not achieve the desired efficacy in PDT due to their poor photostability, targeting ability, and responsiveness. Herein, we designed a series of photosensitizers with aggregation-induced emission (AIE) effect using benzothiazole- triphenylamine (BZT-triphenylamine) as the parent nucleus. The synthesized compound SIN ((E)-2-(4-(diphenylamino)styryl)-3-(4-iodobutyl)benzo[d]thiazol-3-ium) exhibits good biocompatibility, photostability, and bright emission in the near-infrared range (600-800 nm). The fluorescence emission intensity is responsive to viscosity, with significant fluorescence enhancement (48 times) and high fluorescence quantum yield (4.45 %) at high viscosity. Moreover, SIN has particular lysosome targeting properties with a Pearson correlation coefficient (PCC) of 0.97 and has good 1O2 generation ability under white light irradiation, especially in a weak acidic environment. Thus, SIN can realize good bioimaging ability and photodynamic therapeutic efficacy under the highly viscous and weakly acidic environment of lysosomes in the tumor cells. This study indicates that SIN has potential as a multifunctional organic photosensitizer for bioimaging and PDT of tumor.
Assuntos
Neoplasias , Fotoquimioterapia , Humanos , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/uso terapêutico , Fotoquimioterapia/métodos , Neoplasias/diagnóstico por imagem , Neoplasias/tratamento farmacológico , Luz , LisossomosRESUMO
In the complex and severe tumor microenvironment, the antitumor efficiency of nanomedicines is significantly limited by their low-efficacy monotherapy, non-tumor targeting, and systemic toxicity. Herein, to achieve tumor-targeted and enhanced chemodynamic/photothermal therapy (CDT/PTT), we fabricated an "all-in-one" biocompatible transferrin-loaded cobalt ferrate nanoparticle (CoFe2O4@Tf (CFOT)) with multiple functions by a simple solvothermal method and the following transferrin (Tf) functionalization. Upon exposure to 808 nm laser irradiation, CFOT, as a novel photothermal agent, exhibited outstanding phototherapeutic activity because of its excellent photothermal conversion efficiency (η = 46.5%) for high-performance PTT. Moreover, CFOT with multiple redox pairs could efficiently convert endogenous H2O2 to hazardous hydroxyl radicals (ËOH) via Fenton reactions while scavenging overexpressed GSH in the tumor microenvironment to realize self-reinforcing CDT. Importantly, CFOT undergoes a promoted Fenton-type reaction upon increasing the temperature under a photothermal effect and could augment PTT by high-level ËOH, exhibiting a considerably enhanced synergistic therapeutic effect. In vitro and in vivo experimental results demonstrated that CFOT has good potential as an "all-in-one" nanoagent to combine photothermal, chemodynamic, and tumor targeting for efficient tumor elimination.
Assuntos
Nanopartículas , Neoplasias , Humanos , Transferrina , Peróxido de Hidrogênio , Terapia Fototérmica , Neoplasias/tratamento farmacológico , Cobalto/farmacologia , Microambiente Tumoral , Linhagem Celular TumoralRESUMO
Icariside I, the glycosylation product of icaritin, is a novel effective anti-cancer agent with immunological anti-tumor activity. However, very limited natural icariside I content hinders its direct extraction from plants. Therefore, we employed a computer-aided protein design strategy to improve the catalytic efficiency and substrate specificity of the α-L-rhamnosidase from Thermotoga petrophila DSM 13995, to provide a highly-efficient preparation method. Several beneficial mutants were obtained by expanding the active cavity. The catalytic efficiencies of all mutants were improved 16-200-fold compared with the wild-type TpeRha. The double-point mutant DH was the best mutant and showed the highest catalytic efficiency (k cat /K M : 193.52 s-1 M-1) against icariin, which was a 209.76-fold increase compared with the wild-type TpeRha. Besides, the single-point mutant H570A showed higher substrate specificity than that of the wild-type TpeRha in hydrolysis of different substrates. This study provides enzyme design strategies and principles for the hydrolysis of rhamnosyl natural products.
RESUMO
AIMS: The emerging of drug resistant Pseudomonas aeruginosa is a critical challenge and renders an urgent action to discover innovative antimicrobial interventions. One of these interventions is to disrupt the pseudomonas quinolone signal (pqs) quorum sensing (QS) system, which governs multiple virulence traits and biofilm formation. This study aimed to investigate the QS inhibitory activity of a series of new PqsR inhibitors bearing a quinoline scaffold against Ps. aeruginosa. METHODS AND RESULTS: The results showed that compound 1 suppressed the expression of QS-related genes and showed the best inhibitory activity to the pqs system of wild-type Ps. aeruginosa PAO1 with an IC50 of 20.22 µmol L-1 . The virulence factors including pyocyanin, total protease, elastase and rhamnolipid were significantly suppressed in a concentration-dependent manner with the compound. In addition, compound 1 in combination with tetracycline inhibited synergistically the bacterial growth and suppressed the biofilm formation of PAO1. The molecular docking studies also suggested that compound 1 could potentially interact with the ligand-binding domain of the Lys-R type transcriptional regulator PqsR as a competitive antagonist. CONCLUSIONS: The quinoline-based derivatives were found to interrupt the quorum sensing system via the pqs pathway and thus the production of virulence factors was inhibited and the antimicrobial susceptibility of Ps. aeruginosa was enhanced. SIGNIFICANCE AND IMPACT OF STUDY: The study showed that the quinoline-based derivatives could be used as an anti-virulence agent for treating Ps. aeruginosa infections.
Assuntos
Pseudomonas aeruginosa , Piocianina , Antibacterianos/química , Proteínas de Bactérias/metabolismo , Biofilmes , Endopeptidases/farmacologia , Ligantes , Simulação de Acoplamento Molecular , Elastase Pancreática/metabolismo , Pseudomonas aeruginosa/metabolismo , Piocianina/metabolismo , Percepção de Quorum , Tetraciclinas/farmacologia , Fatores de Virulência/genética , Fatores de Virulência/metabolismoRESUMO
The discovery of small molecular inhibitors targeting essential and conserved bacterial drug targets such as FtsZ protein is a promising approach to fight against multi-drug resistant bacteria. In the present study, two new series of FtsZ inhibitors based on a 1-methylquinolinium scaffold were synthesized. The inhibitors possess a variety of substituent groups including the cyclic or linear amine skeleton at the 2- and 4-position of the quinolinium ring for structure-activity relationship study. In general, the inhibitors bearing a cyclic amine substituent at the 4-position of the quinolinium ring showed better antibacterial activity (MIC down to 0.25 µg/mL) than that at the 2-position, especially against Gram-positive bacteria. Among the twenty FtsZ inhibitors examined in various assays, A3 was identified to exhibit excellent antibacterial activity against S. aureus (MIC = 0.5-1 µg/mL), S. epidermidis (MIC = 0.25 µg/mL) and E. faecium (MIC = 1-8 µg/mL). More importantly, A3 showed low hemolytic toxicity (IC5 = 64 µg/mL) and was found not readily to induce drug resistance. A3 at 2-8 µg/mL promoted the polymerization of FtsZ and interrupted the bacterial division. Furthermore, the ligand-FtsZ interaction study conducted with circular dichroism and molecular docking revealed that A3 induced secondary structure changes of FtsZ protein upon binding to the interdomain cleft of the protein. A3 is thus a potent inhibitor of FtsZ and shows potential to be used as a new antibacterial agent against drug-resistant bacteria.
Assuntos
Proteínas de Bactérias , Staphylococcus aureus , Aminas , Antibacterianos/química , Proteínas do Citoesqueleto , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Staphylococcus aureus/metabolismo , Staphylococcus epidermidis , Relação Estrutura-AtividadeRESUMO
DNA G4-structures from human c-MYC promoter and telomere are considered as important drug targets; however, the developing of small-molecule-based fluorescent binding ligands that are highly selective in targeting these G4-structures over other types of nucleic acids is challenging. We herein report a new approach of designing small molecules based on a non-selective thiazole orange scaffold to provide two-directional and multi-site interactions with flanking residues and loops of the G4-motif for better selectivity. The ligands are designed to establish multi-site interactions in the G4-binding pocket. This structural feature may render the molecules higher selectivity toward c-MYC G4s than other structures. The ligand-G4 interaction studied with 1H NMR may suggest a stacking interaction with the terminal G-tetrad. Moreover, the intracellular co-localization study with BG4 and cellular competition experiments with BRACO-19 may suggest that the binding targets of the ligands in cells are most probably G4-structures. Furthermore, the ligands that either preferentially bind to c-MYC promoter or telomeric G4s are able to downregulate markedly the c-MYC and hTERT gene expression in MCF-7 cells, and induce senescence and DNA damage to cancer cells. The in vivo antitumor activity of the ligands in MCF-7 tumor-bearing mice is also demonstrated.
Assuntos
Antineoplásicos/química , Neoplasias da Mama , Quadruplex G , Animais , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Desenho de Fármacos , Feminino , Genes myc , Humanos , Ligantes , Células MCF-7 , Camundongos , Regiões Promotoras Genéticas , TelômeroRESUMO
Organic small molecules with near-infrared (NIR) absorption hold great promise as the phototheranostic agents for clinical translation by virtue of their inherent merits such as well-defined chemical structure, high purity and good reproducibility. Probes that happen to be based on cyanine dyes exhibit strong NIR-absorbing and efficient photothermal conversion, representing a new class of photothermal agents (PAs) for photothermal therapy (PTT), and taking into account the heat susceptibility of Mitochondria (Mito), we designed and prepared a mitochondria-targeted organic small molecule (Mito-BWQ) based on thiazole orange maternal unit that can effectively kill tumor cells through the hyperpyrexia generated in the lesions under exogenous laser irradiation. The Confocal laser scanning microscope was employed to determine the preferential targeting of Mito-BWQ to the mitochondria of MCF-7 cells and U87 cells. When subjected to 600 nm laser radiation, Mito-BWQ produced an increase in temperature in test systems and this increase was dependent on both the laser power and probe concentration. In vitro tests, cytotoxicity was observed when cells were incubated with Mito-BWQ and exposed to laser irradiation. The PTT in vivo also showed that Mito-BWQ performed remarkably in tumor inhibition. This study thus provides a vital starting point for the creation of thiazole orange-based PTT formulations and promotes further advances in the field of PAs-based anticancer research and therapy.