Percorrer por autor "Froufe, Hugo J.C."
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- 1-aryl-3-(4-(7-methylthieno[3,2-d]pyrimidin-4-yloxy)phenyl)ureas: synthesis and molecular modelling studies using VEGFR-2Publication . Soares, Pedro; Froufe, Hugo J.C.; Abreu, Rui M.V.; Ferreira, Isabel C.F.R.; Borges, Fernanda; Queiroz, Maria João R.P.The development of anticancer drugs inhibiting angiogenesis has been an area of extensive research in the past decade. Angiogenesis is a requirement for tumor growth and metastasis and occurs through several signalling pathways. One key pathway that initiates proliferation and migration of endothelial cells is signalling through the vascular endothelial growth factor receptor-2 (VEGFR-2).1 Therefore, small molecules that block this signalling pathway through inhibition of VEGFR-2 tyrosine kinase activity could potentially inhibit angiogenesis and tumor growth. Recently works describing thienopyrimidine2 and thienopyrimidine 1,3-diarylureas3 as VEGFR-2 inhibitors have emerged in the literature. Here we present the synthesis of new 1-aryl-3-(4-(7-methylthieno[3,2-d]pyrimidin-4-yloxy)phenyl)ureas 2 in high yields by reaction of 4-[(7-methylthieno[3,2-d]pyridin-4-yl)oxy]aniline 1 with arylisocyanates. The former was prepared by regioselective nucleophilic substitution of 4-chloro-7-methylthieno[3,2-d]pyrimidine with 4-aminophenol
- 1-Aryl-3-[ 4-( thieno[3,2-d]pyrimidin-4-yloxy )phenyl]ureas as VEG FR2 inhibitors: synthesis, docking enzymatic and cellular assaysPublication . Peixoto, Daniela; Calhelha, Ricardo C.; Soares, Pedro; Abreu, Rui M.V.; Froufe, Hugo J.C.; Ferreira, Isabel C.F.R.; Costa, Raquel; Soares, Raquel; Queiroz, Maria João R.P.A number of thienopyrimidines derivatives have shown potent VEGFR2 (Vascular Endothelium Growth Factor Receptor2) tyrosine kinase inhibition activity.[ll VEGF is a sun·ogate marker of angiogenesis that activates VEGFR2 in endothelial cells. Here we present the synthesis of new 1-aryl-3-[ 4-(thieno[3,2-d]pyrimidin-4- yloxy)phenyl]ureas from the aminodi(hetero)arylether 1, also prepared by us, which was reacted with arylisocyanates to give the corresponding 1,3-diarylureas 2a-c.
- 1-Aryl-3-[4-(thieno[3,2-d]pyrimidin-4-yloxy)phenyl]ureas as potential inhibitors of VEGFR-2: synthesis and molecular modelling studiesPublication . Soares, Pedro; Froufe, Hugo J.C.; Abreu, Rui M.V.; Ferreira, Isabel C.F.R.; Borges, Fernanda; Queiroz, Maria João R.P.Angiogenesis is a requirement for tumor growth and metastasis and occurs through several signalling pathways. One key pathway that initiates proliferation and migration of endothelial cells is signalling through the vascular endothelial growth factor receptor-2 (VEGFR-2).1 Therefore, small molecules that block this signalling pathway through inhibition of the VEGFR tyrosine kinase activity could potentially inhibit angiogenesis and tumour growth. Recently works describing thienopyrimidines2 and thienopyridine ureas3 as inhibitors of VEGFR-2 have appeared in the literature. Here we present the synthesis of new 1,3-diarylureas 2 starting by regioselective nucleophilic substitution of the 4-chlorothieno[3,2-d]pyrimidine with 4-aminophenol to obtain 4-(thieno[3,2-d]pyridin-4-yloxy)aniline 1 which reacts with different arylisocyanates
- 1-Aryl-3-[4-(thieno[3,2-d]pyrimidin-4-yloxy)phenyl]ureas as VEGFR-2 tyrosine kinase inhibitors: Synthesis, biological evaluation, and molecular modelling studiesPublication . Soares, Pedro; Costa, Raquel; Froufe, Hugo J.C.; Calhelha, Ricardo C.; Peixoto, Daniela; Abreu, Rui M.V.; Ferreira, Isabel C.F.R.; Soares, Raquel; Queiroz, Maria João R.P.The Vascular Endothelial Growth Factor Receptor-2 (VEGFR-2) is a tyrosine kinase receptor involved in the growth and differentiation of endothelial cells that is implicated in tumor-associated angiogenesis. In this study novel 1-aryl-3-[4-(thieno[3,2-d]pyrimidin-4-yloxy)phenyl]ureas were synthesized and evaluated for the VEGFR-2 tyrosine kinase inhibition. Three of these compounds showed good VEGFR-2 inhibition presenting low IC50 values (150-199 nM) in enzymatic assays. The latter promoted also significant inhibition of cell proliferation at low concentrations (0.5-1 µM), not affecting cell viability, of VEGF-stimulated Human Umbilical Vein Endothelial Cells (HUVECs) using the BrdU assay. The determination of the total and phosphorylated (active) VEGFR-2 was performed by western-blot, and it was possible to conclude that the compounds significantly inhibit the phosphorylation of the receptor at 1 µM pointing to their antiproliferative mechanism of action in HUVECs. The molecular rationale for inhibiting the tyrosine kinase domain of VEGFR-2 was also done and discussed using molecular docking studies.
- 1-Aryl-3-[4-(thieno[3,2-d]pyrimidin-4-yloxy)phenyl]ureas as VEGFR2 tyrosine kinase inhibitors: synthesis, docking studies, enzymatic and cellular assaysPublication . Queiroz, Maria João R.P.; Peixoto, Daniela; Soares, Pedro; Abreu, Rui M.V.; Froufe, Hugo J.C.; Calhelha, Ricardo C.; Ferreira, Isabel C.F.R.; Costa, Raquel; Soares, RaquelA number of thienopyrimidines derivatives have shown potent vascular endothelial growth factor receptor 2 (VEGFR2) inhibition activity. Here, we present the synthesis of new 1-aryl-3-[4-(thieno[3,2-d) pyrimidin-4-yloxy)phenyl]ureas by promoting t he regioselective attack of the hydroxy group of the 4-aminophenol in the chlorine nucleophilic displacement on two 4-chlorinated thieno[3,2-d]pyrimidines, obtaining compounds la and 1b which were reacted with arylisocyanates to give t he corresponding 1,3-diarylureas 2a-f (see scheme). These compounds were evaluated for inhibition of VEGFR2 tyrosine kinase activity using enzymatic assays, and 2a- c showed good inhibition ability with IC50 values in the range of hundreds of nanomolar. The rationale for the inhibition activity is also discussed using docking. To examine the activity of 2a- c in endothelial cells, human umbilical vein endothelial cells (HUVECs) were cultured in the presence or absence of each compound in different concentrations. A decrease in the proliferation of HUVECs was observed by the incorporation of BrdU quantified by ELISA assay. Given the established role of VEGFR2 in proliferation and migration of endothelial cells, these molecules are promising antiangiogenic agents that can be used for therapeutic purposes in pathological conditions where angiogenesis is exacerbated, such as cancer.
- Antimicrobial activity of phenolic compounds identified in wild mushrooms, SAR analysis and docking studiesPublication . Alves, Maria José; Ferreira, Isabel C.F.R.; Froufe, Hugo J.C.; Abreu, Rui M.V.; Martins, Anabela; Pintado, ManuelaAim and Methods: Although the antimicrobial activity of extracts from several mushroom species have been reported, studies with the individual compounds present in that extracts are scarce. Herein, the antimicrobial activity of different phenolic compounds identified and quantified in mushroom species from all over the world was evaluated. Furthermore, a structure activity relationship (SAR) analysis and molecular docking studies were performed, in order to provide insights in the mechanism of action of potential antimicrobial drugs for resistant microorganisms. Results: 2,4-Dihydroxybenzoic and protocatechuic acids were the phenolic compounds with higher activity against the majority of Gram negative and Gram positive bacteria. Furthermore, phenolic compounds inhibited more MRSA than methicillin sensible Staphylococcus aureus. MRSA was inhibited by 2,4-dihydroxybenzoic, vanillic, syringic (MICs=0.5 mg/mL) and p-coumaric (MIC= 1 mg/mL) acids, while these compounds at the same concentrations had no inhibitory effects against methicillin sensible Staphylococcus aureus. Conclusions: The presence of carboxylic acid (COOH), two hydroxyl (OH) groups in para and ortho positions of the benzene ring, as also a methoxyl (OCH3) group in the meta position seems to be important for anti-MRSA activity. Significance and Impact of the Study: Phenolic compounds could be used as antimicrobial agents, namely against some microorganisms resistant to commercial antibiotics.
- Aplicação de ferramentas de quimioinformática no desenvolvimento de novos fármacos: tienopiridinas como inibidores de VEGFR-2Publication . Abreu, Rui M.V.; Froufe, Hugo J.C.; Queiroz, Maria João R.P.; Ferreira, Isabel C.F.R.A quimioinformática é uma área científica que utiliza métodos computacionais para resolver problemas de Química normalmente associados à representação virtual da estrutura de compostos químicos, quer sejam sintéticos ou naturais. t: provavelmente a disciplina de computação aplicada com maior historial, embora o termo quimioinformática só tenha surgido há menos de uma década. As ferramentas computacionais utilizadas na quimioinformática têm tido um enorme impacto no desenvolvimento de novos fármacos bem como na área ambiental para a estimativa de toxicidade de produtos químicos existentes no mercado (1 ). As temáticas mais importantes desta área incluem a representação de estruturas de compostos químicos e o uso dessas representações na pesquisa por similaridade em bases de dados de estruturas ou de reações químicas. Também a criação, manutenção, acesso e exploração de grandes bases de dados envolvendo estruturas moleculares é um tópico muito importante na quimioinformática. Outras aplicações incluem estudos de modelação molecular, com a utilização de técnicas computacionais avançadas de "molecular docking" e "molecular dynamics" para o estudo de compostos químicos como potenciais inibidores de proteínas associadas a diferentes patologias (2); bem como estudos QSAR (Quantitative Structure-Activity Relashionships) e aplicação de técnicas de data mining para a extração de informação importante sobre uma determinada bioatividade de um composto químico. Neste sessão vamos utilizar ferramentas computacionais para analisar e manipular estruturas de compostos químicos bem como fazer um estudo da interação de um composto com uma determinada proteína alvo. Vamos demostrar como estas ferramentas podem ser utilizadas para o desenvolvimento de novos fármacos antitumorais. Como exemplos vamos utilizar compostos derivados de tienopiridinas, que estão a ser desenvolvidos no âmbito de um projeto de investigação em curso e que tem como objetivo o desenvolvimento de novos inibidores da proteína tirosina cinase VEGFR-2 (Vascular Endothelial Growth Factor Receptor).
- ChemT, a software for building template-based 3D chemical libraries.Publication . Abreu, Rui M.V.; Froufe, Hugo J.C.; Daniel, Pedro O.M.; Queiroz, Maria João R.P.; Ferreira, Isabel C.F.R.ln the modem drug discovery process vast quantities of compounds are generated and there is a need for bioinformatic tools to efficiently create, manage and examine huge chemical compound libraries. Severa! software tools for drawing and generating chemical compounds structures are available, but they usually lack options for automatic generation of custom-made focused chemicallibraries. We have implemented ChemT (Chemical Templates), a free software too! that automates the process of preparing template-based three-dimensional chemical libraries. ChemT accepts severa! file fonnats and is able to select compounds by imposing limits according to different physicochemical properties or by applying a Lipinski Rule of Fives filter. The compounds on the library are subject to force field minimization and the resulting threedimensional sh·uctures can be recorded on severa! file fonnats more frequently used in Virtual Screening projects. ChemT was developed using C-sharp language and compiled for Windows using SharpDevelop3.5. For file fonnat conversions, properties calculation and compound energy minimization ChemT uses the OpenBabel OBDotNet library. For compound energy minimization ChemT uses the Universal Force Field available with OpenBabel. As supporters of free open-source software ChemT is freely available on his website (www.esa.ipb.pt/~ruiabreu/chemt). ChemT is a fast easy-to-use software that automatically generates three-dimensional chemical libraries by inputting a chemical template and functional groups of interest. A fairly self-explanatory Graphical User Interface is provided and severa! tools for compound filtering are included. ChemT can be a valuable too! for chemists interested in using virtual screening tools in arder to prioritize compounds for further chemical synthesis.
- ChemT, an open-source software for building template-based chemical librariesPublication . Abreu, Rui M.V.; Froufe, Hugo J.C.; Daniel, Pedro O.M.; Queiroz, Maria João R.P.; Ferreira, Isabel C.F.R.Mushrooms represent an unlimited source of compounds with antitumor and immunostimulating properties and mushroom intake as been shown to reduce the risk of breast cancer. A large number of LMW (low molecular weight) compounds present in mushrooms have been identified including: phenolic acids, flavonoids, tocopherols, carotenoids, sugars and fatty acids. In order to evaluate which wild mushroom LMW compounds may be involved in anti-breast cancer activity we selected a representative dataset of 43 LMW compounds and performed molecular docking against 3 known protein targets involved in breast cancer (Aromatase, Estrone Sulfatase and 17β-HSD-1) using AutoDock4 as docking software. The estimated inhibition constants for all LMW compounds were determined and the potential structure-activity relationships for the compounds with the best estimated inhibition constants are discussed for each compound family. 4-O-caffeoylquinic, naringin and lycopene stand out as the top ranked potential inhibitors for Aromatase, Estrone Sulfatase and 17β-HSD1, respectively, and the 3-D docked conformation for these compounds are discussed in detail. This information provides several interesting starting points for further development of Aromatase, Estrone Sulfatase and 17β-HSD1 inhibitors.
- A convenient high performance computing (HPC) methodology for virtual screening using Autodock 4Publication . Abreu, Rui M.V.; Froufe, Hugo J.C.; Ferreira, Isabel C.F.R.; Queiroz, Maria João R.P.