In vitro and in vivo uptake studies of PAMAM G4.5 dendrimers in breast cancer

Background: Breast cancer is the second leading cause of cancer death worldwide. Nanotechnology approaches can overcome the side effects of chemotherapy as well as improve the efficacy of drugs. Dendrimers are nanometric size polymers which are suitable as drug delivery systems. To the best of our knowledge, studies on the application of PAMAM G4.5 (polyamidoamine half generation 4) dendrimers as potential drug delivery systems in breast cancer have not been reported. In this work we developed a PAMAM G4.5 dendrimer containing FITC (fluorescein isothiocyanate) dye to study their uptake by murine breast cancer cells and BALB/c mice breast tumors. Results: We performed a reaction between FITC and PAMAM G4.5 dendrimers which were previously derivatized with piperazine (linker molecule), characterized them by 1H NMR (proton nuclear magnetic resonance) spectroscopy and MALDI-TOF (matrix-assisted laser desorption/ionization- time-of-flight) mass spectrometry. The experimental data indicated that 2 FITC molecules could be bound covalently at the PAMAM G4.5 dendrimer surface, with 17 FITC molecules probably occluded in PAMAM dendrimers cavity. PAMAM-FITC dendrimer (PAMAM G4.5-piperazinyl-FITC dendrimer) size distribution was evaluated by DLS (dynamic light scattering) and TEM (transmission electron microscopy). The nanoparticle hydrodynamic size was 96.3 ± 1.4 nm with a PdI (polydispersion index) of 0.0296 ± 0.0171, and the size distribution measured by TEM was 44.2 ± 9.2 nm. PAMAM-FITC dendrimers were neither cytotoxic in 4T1 cells nor hemolytic up to 24 h of incubation. In addition, they were uptaken in vitro by 4T1 cells and in vivo by BALB/c mice breast tumors. PAMAM G4.5-piperazinyl-FITC dendrimer intracellular distribution was observed through histologic analysis of the tumor by laser confocal microscopy. Conclusion: These results indicate that PAMAM G4.5 dendrimers enter tumor tissue cells, being good candidates to be used as antitumor drug delivery systems for breast cancer treatment and diagnosis

Potencial antitumoral de extratos de Eugenia involucrata DC: uso de produtos regionais para tratar um problema mundial

Artigo apresentado na forma de "banner" na Primeira Mostra Científica e Tecnológica da UFSC CuritibanosNos últimos anos, tem se buscado alternativas mais eficientes e menos tóxicas para a quimioterapia do câncer. Diante disso buscou-se avaliar a atividade antitumoral de extratos da polpa, semente e folha da espécie Eugenia involucrata, nativa do Sul do Brasil. Os extratos vegetais das sementes extraída à 50ºC (S50) e folhas à 22ºC (F22) induziram citotoxicidade em células tumorais PANC-1 demonstrando valores de CC50 iguais a 645 e 596 µg.mL-1, respectivamente, e seletividade para células cancerígenas. A partir da obtenção desses dados, o extrato das folhas passou por um processo de extração líquido-líquido utilizando o solvente hexano (EH), acetato de etila (EAE) e o produto aquoso (EAQ) para selecionar a subfração mais ativa. As frações EAE e EH apresentaram atividade e a fração EAE demonstrou melhor IS, pois não reduziu a viabilidade de células HUVEC até 1000 µg.mL-1. Os resultados obtidos com os extratos foram comparados com o quimioterápico gencitabina, padrão ouro no tratamento do câncer de pâncreas, e se mostraram mais interessantes. As alterações morfológicas características de apoptose foram evidenciadas nas células tratadas com os extratos S50 e F22. O potencial dos extratos em inibir a migração celular e alteração do citoesqueleto também foi avaliado e alguns extratos demonstraram efeito inibitório. Os dados preliminares levam a concluir que a espécie testada apresenta metabólitos de interesse e potencial biológico, o que permite a continuação do estudo em várias frentes de trabalh

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Regulation of SIRT 1 mediated NAD dependent deacetylation: A novel role for the multifunctional enzyme CD38

The SIRT I enzyme is a NAD dependent deacetylase implicated in ageing, cell protection, and energy metabolism in mammalian cells. How the endogenous activity of SIRT I is modulated is not known. The enzyme CD38 is a multifunctional enzyme capable of synthesis of the second messenger, cADPR, NAADP, and ADPR. However, the major enzymatic activity of CD38 is the hydrolysis of NAD. Of particular interest is the fact that CD38 is present on the inner nuclear membrane. Here, we investigate the modulation of the SIRT I activity by CD38. We propose that by modulating availability of NAD to the SIRT1 enzyme, CD38 may regulate SIRT1 enzymatic activity. We observed that in CD38 knockout mice, tissue levels of NAD are significantly increased. We also observed that incubation of purified recombinant SIRT1 enzyme with CD38 or nuclear extracts of wild-type mice led to a significant inhibition of its activity. In contrast, incubation of SIRT I with cellular extract from CD38 knockout mice was without effect. Furthermore, the endogenous activity of SIRT1 was several time higher in nuclear extracts from CD38 knockout mice when compared to wild-type nuclear extracts. Finally, the in vivo deacetylation of the SIRT1 substrate P53 is increased in CD38 knockout mice tissue. Our data support the novel concept that nuclear CD38 is a major regulator of cellular/nuclear NAD level, and SIRT1 activity. These findings have strong implications for understanding the basic mechanisms that modulate intracellular NAD levels, energy homeostasis, as well as ageing and cellular protection modulated by the SIRT enzymes. (c) 2006 Elsevier Inc. All rights reserved

Perfil mecánico de queratinocitos humanos que expresan oncogenes del HPV-18 para caracterizar cambios mecánicos en etapas intermedias de la carcinogénesis oral

OBJETIVOS. Las propiedades mecánicas de las células sufren cambios profundos durante el proceso de tumorigénesis, y son determinantes para comportamientos tumorales tales como la invasión y la metástasis. Nuestro objetivo es estudiar los cambios mecánicos que ocurren en etapas intermedias de este proceso, así como los cambios de morfología celular que frecuentemente acompañan a las alteraciones en el fenotipo mecánico. Para ello, utilizamos queratinocitos humanos (línea celular HaCaT, usada frecuentemente en estudios de biología oral) que expresan los oncogenes del HPV -18, y que constituyen entonces un modelo de etapa intermedia en el proceso de tumorigénesis oral. MÉTODOS. Utilizamos microscopía de fuerza atómica en el modo de nanoindentación y en el modo de mapeo nanomecánico cuantitativo para obtener medidas del módulo de Young y mapas mecánicos de la superficie celular, respectivamente. Además, utilizamos microscopía confocal para obtener parámetros morfológicos celulares. RESULTADOS. Observamos una disminución significativa en el módulo de Young en células HaCaT que expresan los oncogenes del HPV-18, y una disminución de la rigidez en las zonas de contacto célula célula. Por otra parte, la morfología celular se vuelve significativamente más redondeada en las células HaCaT que expresan los oncogenes del HPV-18. CONCLUSIONES. Nuestros resultados apoyan la hipótesis de que la disminución en la rigidez celular es un cambio mecánico que ocurre en etapas tempranas de la tumorigénesis oral, y que puede estar acompañado de cambios en la morfología celula

De las nanobiomoléculas a la nanobiología y nanomedicina

Resumen: Actualmente, estamos en una etapa en la que las ciencias biom.dicas buscan mejorar el diagnóstico y la terapia de varias enfermedades, por medio del empleo de novedosos dispositivos a escala nanométrica. Micelas poliméricas, liposomas, dendrímeros y nanopartículas biodegradables, son algunos ejemplos de nanomateriales que se investigan en los laboratorios, que están en fase pre-clínica o ya se emplean en la clínica. En este momento se cuenta con numerosos nuevos sistemas nanoestructurados con múltiples y potenciales aplicaciones en el área biomédica. Sin embargo, a pesar de que en muchos casos se han realizado caracterizaciones fisicoquímicas de los mismos, no se ha estudiado su interacción con diferentes sistemas biológicos y con las nanobiomoléculas que los componen. En este artículo, mostramos la evolución del trabajo que estamos llevando a cabo en nuestro laboratorio. En primera instancia, describimos las investigaciones que hemos realizado estudiando diferentes nanobiomoléculas. Nuestro objetivo es intentar entender la señalización y regulación de procesos biológicos como la síntesis de proteínas en el sistema nervioso o la síntesis de ARN en el núcleo celular. En segunda instancia, describimos estudios que estamos realizando utilizando dendrímeros y analizando sus posibles aplicaciones en el tratamiento de enfermedades como el parto prematuro, el cáncer o la diabetes. Por último, describimos brevemente la microscopía de fuerza atómica y sus aplicaciones en ciencias biológicas y biomédicas, finalizando con un ejemplo concreto de nuestra investigación

The value of open-source clinical science in pandemic response: lessons from ISARIC

International audienc