RESUMEN
Tumor-specific, hypoxia-activated prodrugs have been developed to alleviate the side effects of chemotherapy drugs. However, the release efficiency of hypoxia-activated prodrugs is restricted by the degree of tumor hypoxia, which further leads to poor cancer treatment effects. On the other hand, oxygen is consumed gradually in photodynamic therapy (PDT), which aggravates hypoxia at the tumor site. In this study, we combined hypoxia-activated prodrugs with PDT agents to promote the prodrugs release, thereby improving their bioavailability and therapeutic effects. As a proof of concept, a mitochondria-targeted molecular prodrug, CS-P, was designed and synthesized. It can be selectively activated by tumor hypoxia to release chemotherapeutic drugs and photosensitizers, and then further discharge drugs after light irradiation. The design strategy proposed in this paper provides a new idea for enhancing hypoxia-activated prodrug release and real-time monitoring prodrug release.
Asunto(s)
Nanopartículas , Neoplasias , Fotoquimioterapia , Profármacos , Línea Celular Tumoral , Humanos , Hipoxia , Neoplasias/tratamiento farmacológico , Fármacos Fotosensibilizantes/farmacología , Fármacos Fotosensibilizantes/uso terapéutico , Profármacos/farmacología , Profármacos/uso terapéuticoRESUMEN
Hydrogen sulfide (H2S) is connected with various physiological and pathological functions. However, understanding the important functions of H2S remains challenging, in part because of the lack of tools for detecting endogenous H2S. Herein, compounds Ratio-H2S 1/2 are the first FRET-based mitochondrial-targetable dual-excitation ratiometric fluorescent probes for H2S on the basis of H2S-promoted thiolysis of dinitrophenyl ether. With the enhancement of H2S concentration, the excitation peak at λ≈402â nm of the phenolate form of the hydroxycoumarin unit drastically increases, whereas the excitation band centered at λ≈570â nm from rhodamine stays constant and can serve as a reference signal. Thus, the ratios of fluorescence intensities at λ=402 and 570â nm (I402/I570) exhibit a drastic change from 0.048 in the absence of H2S to 0.36 in the presence of 180â µM H2S; this is a 7.5-fold variation in the excitation ratios. The favorable properties of the probe include the donor and acceptor excitation bands, which exhibit large excitation separations (up to 168â nm separation) and comparable excitation intensities, high sensitivity and selectivity, and function well at physiological pH. In addition, it is demonstrated that the probe can localize in the mitochondria and determine H2S in living cells. It is expected that this strategy will lead to the development of a wide range of mitochondria-targetable dual-excitation ratiometric probes for other analytes with outstanding spectral features, including large separations between the excitation wavelengths and comparable excitation intensities.
Asunto(s)
Transferencia Resonante de Energía de Fluorescencia/métodos , Colorantes Fluorescentes/química , Sulfuro de Hidrógeno/análisis , Mitocondrias/metabolismo , Imagen Molecular/métodos , Técnicas de Cultivo de Célula , Supervivencia Celular/efectos de los fármacos , Colorantes Fluorescentes/síntesis química , Colorantes Fluorescentes/farmacocinética , Colorantes Fluorescentes/toxicidad , Humanos , Sulfuro de Hidrógeno/metabolismo , Células MCF-7 , Estructura MolecularRESUMEN
A new rhodamine-based probe 1 was designed and synthesized as a new fluorescent molecular probe for HClO in PBS buffer at physiological condition. The free probe 1 almost nonfluorescence, however, a drastic enhancement of fluorescence intensity was observed in the presence of HClO. The new probe 1 exhibits good sensitivity and selectivity for HClO over other reactive oxygen and/or nitrogen species in PBS buffer, and the probe was successfully applied to image endogeneous HClO in the living cells.
Asunto(s)
Colorantes Fluorescentes/química , Colorantes Fluorescentes/metabolismo , Ácido Hipocloroso/metabolismo , Imagen Molecular/métodos , Rodaminas/química , Rodaminas/metabolismo , Absorción , Animales , Tampones (Química) , Línea Celular , Permeabilidad de la Membrana Celular , Supervivencia Celular , Colorantes Fluorescentes/síntesis química , Concentración de Iones de Hidrógeno , Ratones , Rodaminas/síntesis química , Espectrometría de Fluorescencia , Factores de Tiempo , Agua/químicaRESUMEN
Nuclear factor-kappa B (NF-kappaB) regulates the expression of various genes, several genes involved in inflammation and tumorigenesis, including those of the liver. A role for NF-kappaB has been implicated in the pathogenesis of hepatocellular carcinoma. This transcription factor can regulate hTERT gene transcription. Expression of hTERT was found to be at high levels in hepatocellular carcinoma. However, positive effects of NF-kappaB on hTERT protein synthesis in HepG(2) cells are unknown. In this study, we show that LPS (specific binding to TLR4 to activate NF-kappaB) was positive for NF-kappaB p65 mRNA expression and activation, and also up-regulated hTERT mRNA and protein expressions at 36h in a dose-dependent manner. In contrast, MG-132 (blocking the activity of 26S proteasome and thereby preventing nuclear translocation of NF-kappaB) significantly inhibited activation of NF-kappaB and mRNA expression. And also reduced the expression of hTERT at both mRNA and protein levels at 36h in a dose-dependent manner. Furthermore, dexamethasone inhibited LPS-induced activation of NF-kappaB and expression of the hTERT in HepG(2) cells. These findings suggest that NF-kappaB may modulate hTERT mRNA level, importantly, in protein level in HepG(2) cells and dexamethasone inhibits LPS-induced hTERT via blocking NF-kappaB.
Asunto(s)
Carcinoma Hepatocelular/patología , Telomerasa/genética , Telomerasa/metabolismo , Factor de Transcripción ReIA/metabolismo , Supervivencia Celular/efectos de los fármacos , Dexametasona/farmacología , Relación Dosis-Respuesta a Droga , Células Hep G2 , Humanos , Leupeptinas/farmacología , Lipopolisacáridos/farmacología , Terapia Molecular Dirigida , Complejo de la Endopetidasa Proteasomal , Inhibidores de Proteasoma , Biosíntesis de Proteínas/efectos de los fármacos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Telomerasa/biosíntesis , Factores de Tiempo , Transcripción Genética/efectos de los fármacos , Regulación hacia Arriba/efectos de los fármacosRESUMEN
Probe 1 was designed and synthesized as a new fluorescent molecular probe for thiols in PBS buffer at physiological condition. This fluorescent molecular probe consists of a thiol reaction moiety bound to a coumarin fluorophore. Its fluorescence quantum yield is low, but a drastic enhancement of fluorescence intensity was observed in the presence of thiols. Possible interference with other analytes was examined. Probe 1 displays a highly selective fluorescent enhancement with thiols, and the probe was successfully applied to thiols determination in intracellular, in human urine and blood samples.