RESUMEN
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.
Asunto(s)
G-Cuádruplex , Neoplasias , Humanos , Células HeLa , Ligandos , ARN/metabolismo , Citoplasma/metabolismoRESUMEN
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.
Asunto(s)
Pseudomonas aeruginosa , Piocianina , Antibacterianos/química , Proteínas Bacterianas/metabolismo , Biopelículas , Endopeptidasas/farmacología , Ligandos , Simulación del Acoplamiento Molecular , Elastasa Pancreática/metabolismo , Pseudomonas aeruginosa/metabolismo , Piocianina/metabolismo , Percepción de Quorum , Tetraciclinas/farmacología , Factores de Virulencia/genética , Factores de Virulencia/metabolismoRESUMEN
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.
Asunto(s)
Mitofagia , Neoplasias , Humanos , Células HeLa , Colorantes Fluorescentes/química , Imagen Óptica/métodos , AutofagiaRESUMEN
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.
Asunto(s)
Antineoplásicos , Regulación hacia Abajo , G-Cuádruplex , Regiones Promotoras Genéticas , Telomerasa , Neoplasias de la Mama Triple Negativas , Telomerasa/antagonistas & inhibidores , Telomerasa/metabolismo , Humanos , G-Cuádruplex/efectos de los fármacos , Neoplasias de la Mama Triple Negativas/tratamiento farmacológico , Neoplasias de la Mama Triple Negativas/patología , Animales , Ligandos , Femenino , Regulación hacia Abajo/efectos de los fármacos , Ratones , Antineoplásicos/farmacología , Antineoplásicos/química , Antineoplásicos/uso terapéutico , Línea Celular Tumoral , Bibliotecas de Moléculas Pequeñas/química , Bibliotecas de Moléculas Pequeñas/farmacología , Apoptosis/efectos de los fármacos , Ensayos Antitumor por Modelo de Xenoinjerto , Ratones Desnudos , Senescencia Celular/efectos de los fármacos , Ratones Endogámicos BALB CRESUMEN
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).
Asunto(s)
Antineoplásicos , Neoplasias Colorrectales , G-Cuádruplex , Mitocondrias , Humanos , G-Cuádruplex/efectos de los fármacos , Ligandos , Animales , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Antineoplásicos/farmacología , Antineoplásicos/química , Antineoplásicos/síntesis química , Antineoplásicos/uso terapéutico , Ratones , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/patología , Neoplasias Colorrectales/metabolismo , Apoptosis/efectos de los fármacos , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Ratones Desnudos , Bibliotecas de Moléculas Pequeñas/química , Bibliotecas de Moléculas Pequeñas/farmacología , Bibliotecas de Moléculas Pequeñas/síntesis química , Ensayos Antitumor por Modelo de Xenoinjerto , Células HCT116 , ADN Mitocondrial/metabolismoRESUMEN
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.
Asunto(s)
Proteínas Bacterianas , Staphylococcus aureus , Aminas , Antibacterianos/química , Proteínas del Citoesqueleto , Pruebas de Sensibilidad Microbiana , Simulación del Acoplamiento Molecular , Staphylococcus aureus/metabolismo , Staphylococcus epidermidis , Relación Estructura-ActividadRESUMEN
A series of fluorescent ligands, which were systematically constructed from thiazole orange scaffold, was investigated for their interactions with G-quadruplex structures and antitumor activity. Among the ligands, compound 3 was identified to exhibit excellent specificity toward telomere G4-DNA over other nucleic acids. The affinity of 3-Htg24 was almost 5 times higher than that of double-stranded DNA and promoter G4-DNA. Interaction studies showed that 3 may bind to both G-tetrad and the lateral loop near the 5'-end. The intracellular colocalization with BG4 and competition studies with BRACO19 reveal that 3 may interact with G4-structures. Moreover, 3 reduces the telomere length and downregulates hTERC and hTERT mRNA expression in HeLa cells. The cytotoxicity of 3 against cancer cells (IC50 = 12.7-16.2 µM) was found to be generally higher than noncancer cells (IC50 = 52.3 µM). The findings may support that the ligand is telomere G4-DNA specific and may provide meaningful insights for anticancer drug design.
Asunto(s)
Benzotiazoles/farmacología , ADN/metabolismo , Regulación hacia Abajo/efectos de los fármacos , Colorantes Fluorescentes/farmacología , G-Cuádruplex , Quinolinas/farmacología , Estirenos/farmacología , Benzotiazoles/síntesis química , Benzotiazoles/metabolismo , Línea Celular Tumoral , ADN/genética , Colorantes Fluorescentes/síntesis química , Colorantes Fluorescentes/metabolismo , Humanos , Ligandos , Microscopía Confocal , Microscopía Fluorescente , Quinolinas/síntesis química , Quinolinas/metabolismo , ARN/metabolismo , Estirenos/síntesis química , Estirenos/metabolismo , Telomerasa/metabolismoRESUMEN
A small-sized c-MYC promoter G-quadruplex selective fluorescent BZT-Indolium binding ligand was demonstrated for the first time as a highly target-specific and photostable probe for in vitro staining and live cell imaging and it was found to be able to inhibit the amplification of the c-MYC G-rich sequence (G-quadruplex) and down-regulate oncogene c-MYC expression in human cancer cells (HeLa).