Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Mais filtros

Base de dados
Intervalo de ano de publicação
Front Chem ; 9: 707876, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34249874


Phototherapies, in the form of photodynamic therapy (PDT) and photothermal therapy (PTT), are very promising treatment modalities for cancer since they provide locality and turn-on mechanism for toxicity, both of which are critical in reducing off-site toxicity. Irradiation of photosensitive agents demonstrated successful therapeutic outcomes; however, each approach has its limitations and needs to be improved for clinical success. The combination of PTT and PDT may work in a synergistic way to overcome the limitations of each method and indeed improve the treatment efficacy. The development of single photosensitive agents capable of inducing both PDT and PTT is, therefore, extremely advantageous and highly desired. Cyanine dyes are shown to have such potential, hence have been very popular in the recent years. Luminescence of cyanine dyes renders them as phototheranostic molecules, reporting the localization of the photosensitive agent prior to irradiation to induce phototoxicity, hence allowing image-guided phototherapy. In this review, we mainly focus on the cyanine dye-based phototherapy of different cancer cells, concentrating on the advancements achieved in the last ten years.

J Photochem Photobiol B ; 217: 112171, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33711563


Dual phototherapy agents have attracted great interest in recent years as they offer enhanced cytotoxicity on cancer cells due to the synergistic effect of photodynamic and photothermal therapies (PDT/PTT). In this study, we demonstrate a brominated hemicyanine (HC-1), which is previously shown as mitochondria targeting PDT agent, can also serve as an effective photosensitizer for PTT for the first time under a single (640 nm or 808 nm) and dual laser (640 nm + 808 nm) irradiation. Generation of reactive oxygen species and photothermal conversion as a function of irradiation wavelength and power were studied. Both single wavelength irradiations caused significant phototoxicity in colon and cervical cancer cells after 5 min of irradiation. However, co-irradiation provided near-complete elimination of cancer cells due to synergistic action. This work introduces an easily accessible small molecule-based synergistic phototherapy agent, which holds a great promise towards the realization of local, rapid and highly efficient treatment modalities against cancer.

Apoptose/efeitos dos fármacos , Carbocianinas/farmacologia , Lasers , Fármacos Fotossensibilizantes/farmacologia , Apoptose/efeitos da radiação , Carbocianinas/uso terapêutico , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Citometria de Fluxo , Humanos , Neoplasias/patologia , Neoplasias/terapia , Fotoquimioterapia , Fármacos Fotossensibilizantes/uso terapêutico , Fototerapia , Oxigênio Singlete/química , Oxigênio Singlete/metabolismo
J Photochem Photobiol B ; 201: 111648, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31710924


Superparamagnetic iron oxide nanoparticles (SPIONs) have been recently recognized as highly efficient photothermal therapy (PTT) agents. Here, we demonstrate, for the first time to our knowledge, dose and laser intensity dependent PTT potential of small, spherical, 3-aminopropyltrimethoxysilane coated cationic superparamagnetic iron oxide nanoparticles (APTMS@SPIONs) in aqueous solutions upon irradiation at 795 nm. Indocyanine green (ICG) which has been recently used for photodynamic therapy (PDT), was loaded to APTMS@SPIONs to improve the stability of ICG and to achieve an effective mild PTT and PDT (dual therapy) combination for synergistic therapeutic effect on cancer cells via a single laser treatment in the near infrared (NIR). Neither APTMS@SPIONs nor ICG-APTMS@SPIONs showed dark toxicity on MCF7 breast and HT29 colon cancer cell lines. A safe laser procedure was determined as 10 min irradiation at 795 nm with 1.8 W/cm2 of laser intensity, at which APTMS@SPION did not cause a significant cell death. However, free ICG reduced cell viability at and above 10 µg/ml under these conditions along with generation of reactive oxygen species (ROS), more effectively in MCF7. ICG-APTMS@SPION treated cells showed 2-fold increase in ROS generation and near complete cell death at and below 5 µg/ml ICG dose, even in less sensitive HT29 cells after a single laser treatment at NIR, which would be safe for the healthy tissue and provide a longer penetration depth. Besides, both components can be utilized for diagnosis and the overall composition may be used for optical-image guided phototherapy in the NIR region.

Verde de Indocianina/química , Nanopartículas de Magnetita/toxicidade , Propilaminas/química , Silanos/química , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Humanos , Verde de Indocianina/farmacologia , Raios Infravermelhos , Nanopartículas de Magnetita/química , Nanopartículas de Magnetita/uso terapêutico , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Neoplasias/terapia , Fotoquimioterapia , Fototerapia , Espécies Reativas de Oxigênio/metabolismo , Temperatura
Biophys Chem ; 218: 47-57, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27648754


Elastin is a protein of the extracellular matrix that contributes significantly to the elasticity of connective tissues. In this study, we examine dynamical and structural modifications of aortic elastin exposed to cholesterol by NMR spectroscopic and relaxation methodologies. Macroscopic measurements are also presented and reveal that cholesterol treatment may cause a decrease in the stiffness of tissue. 2H NMR relaxation techniques revealed differences between the relative populations of water that correlate with the swelling of the tissue following cholesterol exposure. 13C magic-angle-spinning NMR spectroscopy and relaxation methods indicate that cholesterol treated aortic elastin is more mobile than control samples. Molecular dynamics simulations on a short elastin repeat VPGVG in the presence of cholesterol are used to investigate the energetic and entropic contributions to the retractive force, in comparison to the same peptide in water. Peptide stiffness is observed to reduce following cholesterol exposure due to a decrease in the entropic force.

Colesterol/farmacologia , Elastina/química , Animais , Aorta/química , Elasticidade/efeitos dos fármacos , Elastina/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Simulação de Dinâmica Molecular , Suínos , Termodinâmica , Água/análise , Água/química
Biophys J ; 108(7): 1758-1772, 2015 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-25863067


Elastin, the principal component of the elastic fiber of the extracellular matrix, imparts to vertebrate tissues remarkable resilience and longevity. This work focuses on elucidating dynamical and structural modifications of porcine aortic elastin exposed to glucose by solid-state NMR spectroscopic and relaxation methodologies. Results from macroscopic stress-strain tests are also presented and indicate that glucose-treated elastin is mechanically stiffer than the same tissue without glucose treatment. These measurements show a large hysteresis in the stress-strain behavior of glucose-treated elastin-a well-known signature of viscoelasticity. Two-dimensional relaxation NMR methods were used to investigate the correlation time, distribution, and population of water in these samples. Differences are observed between the relative populations of water, whereas the measured correlation times of tumbling motion of water across the samples were similar. (13)C magic-angle-spinning NMR methods were applied to investigate structural and dynamical modifications after glucose treatment. Although some overall structure is preserved, the process of glucose exposure results in more heterogeneous structures and slower mobility. The correlation times of tumbling motion of the (13)C-(1)H internuclear vectors in the glucose-treated sample are larger than in untreated samples, pointing to their more rigid structure. The (13)C cross-polarization spectra reveal a notably increased α-helical character in the alanine motifs after glucose exposure. Results from molecular dynamics simulations are provided that add further insight into dynamical and structural changes of a short repeat, [VPGVG]5, an alanine pentamer, desmosine, and isodesmosine sites with and without glucose. The simulations point to changes in the entropic and energetic contributions in the retractive forces of VPGVG and AAAAA motifs. The most notable change is the increase of the energetic contribution in the retractive force due to peptide-glucose interactions of the VPGVG motif, which may play an important role in the observed stiffening in glucose-treated elastin.

Elastina/química , Glucose/farmacologia , Motivos de Aminoácidos , Animais , Aorta/química , Elasticidade , Elastina/metabolismo , Glucose/química , Simulação de Dinâmica Molecular , Ligação Proteica , Estrutura Terciária de Proteína , Suínos , Viscosidade