Navegando por Autor "Bressan, Gustavo Costa"
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Item Achievement of constitutive fluorescent pLEXSY-egfp Leishmania braziliensis and its application as an alternative method for drug screening in vitro(Memórias do Instituto Oswaldo Cruz, 2016-10-20) Bastos, Matheus Silva e; Souza, Luciana Ângelo de; Onofre, Thiago Souza; Almeida, Márcia Rogéria de; Bressan, Gustavo Costa; Fietto, Juliana Lopes Rangel; Silva Júnior, AbelardoGene reporter-fluorescent cells have emerged as alternative method for drug screening. Achievement of constitutive expression of fluorescent protein GFP by Leishmania braziliensis as alternative method for drug screening. L. braziliensis-GFP was generated using Leishmania tarentolae pLEXSY-egfp for constitutive expression of GFP. Fluorescent cells were selected and subjected to standardisation tests of anti-promastigote and anti-intracellular amastigote assays. Our results showed that L. braziliensis-GFP method is faster and more sensitive than Allamar Blue-resazurin. Transfected parasites maintained stable fluorescence after successive in vitro passages and pLEXSY system can be used to achieve non-L. tarentolae fluorescent cells.Item The Antileishmanial Potential of C-3 Functionalized Isobenzofuranones against Leishmania (Leishmania) Infantum Chagasi(Molecules, 2015-12-14) Pereira, Wagner Luiz; Vasconcellos, Raphael de Souza; Mariotini-Moura, Christiane; Gomes, Rodrigo Saar; Firmino, Rafaela de Cássia; Silva, Adalberto Manoel da; Silva Júnior, Abelardo; Bressan, Gustavo Costa; Almeida, Márcia Rogéria; Afonso, Luís Carlos Crocco; Teixeira, Róbson Ricardo; Fietto, Juliana Lopes RangelLeishmaniases are diseases caused by protozoan parasites of the genus Leishmania. Clinically, leishmaniases range from cutaneous to visceral forms, with estimated global incidences of 1.2 and 0.4 million cases per year, respectively. The treatment of these diseases relies on multiple parenteral injections with pentavalent antimonials or amphotericin B. However, these pharmaceuticals are either too toxic or expensive for routine use in developing countries. These facts call for safer, cheaper, and more effective new antileishmanial drugs. In this investigation, we describe the results of the assessment of the activities of a series of isobenzofuran-1(3H)-ones (phtalides) against Leishmania (Leishmania) infantum chagasi, which is the main causative agent of visceral leishmaniasis in the New World. The compounds were tested at concentrations of 100, 75, 50, 25 and 6.25 µM over 24, 48, and 72 h. After 48 h of treatment at the 100 µM concentration, compounds 7 and 8 decreased parasite viability to 4% and 6%, respectively. The concentration that gives half-maximal responses (LC50) for the antileishmanial activities of compounds 7 and 8 against promastigotes after 24 h were 60.48 and 65.93 µM, respectively. Additionally, compounds 7 and 8 significantly reduced parasite infection in macrophages.Item Distribution of infectious bronchitis virus strains in different organs and evidence of vertical transmission in natural infection(Archives of Virology, 2016-09-01) Pereira, Claiton Gonçalves; Saraiva, Giuliana Loreto; Vidigal, Pedro Marcus Pereira; Fietto, Juliana Lopes Rangel; Bressan, Gustavo Costa; Moreira, Maria Aparecida Scatamburlo; Almeida, Márcia Rogéria de; Silva Júnior, AbelardoOn the basis of partial sequencing of the infectious bronchitis virus (IBV) S1 gene, this study investigated the molecular diversity of the virus in two life periods of a batch of breeding hens at the field level. The chicks were vaccinated against IBV on the second day of life with the vaccine Ma5, but at the age of 18 days, they exhibited clinical signs and macroscopic lesions compatible with avian infectious bronchitis (IB). In the clinical disease stage, the Ma5 vaccine strain was detected in the trachea, lungs, and small intestine of the chicks, while IBV variants were detected in the bursa of Fabricius and kidneys. Subsequently, new samples were collected from the same batch at the end of the production cycle. In this phase, the Ma5 vaccine strain was detected in the kidneys, small intestine, and oviduct of the hens. However, a previously unidentified IBV variant was found in the cecal tonsils. Additionally, a fragment of viral RNA with that was completely identical to the corresponding region of the Ma5 vaccine was detected in the allantoic fluid of viable embryos from the hens under study after 18 days of incubation. These findings suggest that, in addition to the Ma5 vaccine, other strains of IBV variants can coexist, seeming to establish a chronic infection in the chickens, and that they can potentially be transmitted vertically. These results may assist in immunoprophylaxis control programs against IBVItem Evaluation of the antiviral activities of Bacharis dracunculifolia and quercetin on Equid herpesvirus 1 in a murine model(Research in Veterinary Science, 2018-10) Ferreira, Caroline Gracielle Torres; Campos, Mateus Gandra; Felix, Daniele Mendes; Santos, Marcus Rebouças; Carvalho, Otávio Valério de; Diaz, Marisa Alves Nogueira; Fietto, Juliana Lopes Rangel; Bressan, Gustavo Costa; Silva-Júnior, Abelardo; Almeida, Márcia Rogéria deEquid herpesvirus 1 (EHV-1) is a pathogen of high economic importance in equine breeding operations around the world. EHV-1 infection causes respiratory, neurologic and reproductive disease. The absence of an efficient therapy has caught the attention of the scientific community and the therapeutic activities of natural products with its antivirals effects might be effective for the disease's treatment. Herein it was evaluated the prophylactic and therapeutic potential of quercetin and ethanolic extracts of Bacharis dracunculifolia formulations compared to Penciclovir® in an in vivo EHV-1 infection model. Six to seven-week-old female C57BL/6 mice were randomly organized into fifteen groups with six animals each. Ex-1 represents the treatment post-challenge groups to assess morbidity, mortality and weight variation. Ex-2 represents the animals that received treatment for 5 days post-challenge for lesion evaluation. In Ex-3 animals were treated prior to viral challenge to assess morbidity, mortality and weight variation. All mice in the treatment groups were challenged by intranasal inoculation of 3.0 × 105 TCID50 EHV-1. The quercetin and B. dracunculifolia treatment decreased morbimortality in post-challenge treatment (Ex-1) and EHV-1 related lesions (Ex-2). Treatment prior to viral challenge (Ex-3) did not show any significant results. Based on the results of the present study, both tested formulations are promising antiviral agents for the treatment of EHV-1 infection.Item Evaluation of the genetic variability found in Brazilian commercial vaccines for infectious bronchitis virus(Virus Genes, 2017-11-11) Saraiva, Giuliana Loreto; Santos, Marcus Rebouças; Pereira, Claiton Gonçalves; Vidigal, Pedro Marcus Pereira; Fietto, Juliana Lopes Rangel; Mendes, Tiago Antonio de Oliveira; Bressan, Gustavo Costa; Soares-Martins, Jamária A. P.; Almeida, Márcia Rogéria de; Silva-Júnior, AbelardoInfectious bronchitis virus (IBV) is currently one of the most important pathogens in the poultry industry. The H120 and Ma5 are the only viral strains approved by the Brazilian government as the constituent of vaccines. Despite the systematic vaccination in Brazil, IBV has not yet been controlled and diseases associated with this virus have been reported in vaccinated chickens. Here, we investigated the genetic variability of H120 and Ma5 strains present in the IBV vaccines from different Brazilian manufacturers. We performed DNA sequencing analyses of the S1 spike glycoprotein gene to investigate its genetic variability and the presence of viral subpopulations among vaccines, between batches, and also in each vaccine after a single passage was performed in chicken embryonated eggs. Our results revealed up to 13 amino acid substitutions among vaccines and some of them were localized in regions of the S1 glycoprotein that play a role in virus–host interaction. Secondary nucleotide peaks identified in the chromatogram for the S1 gene sequence revealed that all original vaccines (H120 and Ma5) were composed by different subpopulations of IBV. Moreover, new viral subpopulations were also found in vaccines after a single passage in chicken embryonated eggs. These findings indicate that H120 and Ma5 viral strains used in vaccines market in Brazil can still mutate very rapidly during replication, leading to amino acid substitutions in proteins involved in the stimulation of the immune response, such as the S1 glycoprotein. Therefore, our data suggest that the genetic variability of these viral strains should be taken into consideration to ensure an effective immune response against IBV.Item Evidence for the association of the human regulatory protein Ki-1/57 with the translational machinery(FEBS Letters, 2011-08-19) Gonçalves, Kaliandra de Almeida; Bressan, Gustavo Costa; Saito, Ângela; Morello, Luis Gustavo; Zanchin, Nilson Ivo T.; Kobarg, JörgKi-1/57 is a cytoplasmic and nuclear protein of 57 kDa first identified in malignant cells from Hodgkin’s lymphoma. Based on yeast-two hybrid protein interaction we found out that Ki-1/57 interacts with adaptor protein RACK1 (receptor of activated kinase 1), CIRP (cold-inducible RNA-binding protein), RPL38 (ribosomal protein L38) and FXR1 (fragile X mental retardation-related protein 1). Since these proteins are involved in the regulation of translation we suspected that Ki-1/57 may have a role in it. We show by immunoprecipitation the association of Ki-1/57 with FMRP. Confocal microscopy revealed that Ki-1/57 colocalizes with FMRP/FXR1/2 to stress granules. Furthermore Ki-1/57 cosediments with free ribosomal particles and enhances translation, when tethered to a reporter mRNA, suggesting that Ki-1/57 may be involved in translational regulation.Item Evolutionary analysis of porcine circovirus 3 (PCV3) indicates an ancient origin for its current strains and a worldwide dispersion(Virus Genes, 2018-03-03) Saraiva, Giuliana Loreto; Vidigal, Pedro Marcus Pereira; Fietto, Juliana Lopes Rangel; Bressan, Gustavo Costa; Silva Júnior, Abelardo; Almeida, Márcia Rogéria dePorcine circovirus 3 (PCV3) is an emerging virus that was identified in the United States in 2016. Since its first identification, PCV3 has been identified in Brazil, China, United States, Poland, and Republic of Korea. In this study, we used molecular phylogenetic analysis of available sequences to address questions surrounding the emergence of PCV3 in porcine world industry. Our data indicate that PCV3 did not emerge through recombination events among currently known circoviruses and that its speciation is not a recent evolutionary event. The most common recent ancestor analysis suggests that PCV3 lineages have emerged over the past 50 years. PCV3 is not genetically closely related with other Porcine circovirus and it has been evolving undetected for some time in swine and probably in bovine population. We also found groups of genetically related isolates of PCV3 originated from different countries that may be associated with dispersal routes, suggesting that PCV3 has already been circulating in pig-producing countries for some time before its first detection.Item Leishmania infantum ecto-nucleoside triphosphate diphosphohydrolase-2 is an apyrase involved in macrophage infection and expressed in infected dogs(Plos One, 2014-11-13) Vasconcellos, Raphael De Souza; Mariotini-Moura, Christiane; Gomes, Rodrigo Saar; Serafim, Tiago Donatelli; Firmino, Rafaela de Cássia; Bastos, Matheus Silva e; Castro, Felipe Freitas de; Oliveira, Claudia Miranda de; Borges-Pereira, Lucas; Souza, Anna Cláudia Alves de; Souza, Ronny Francisco de; Gómez, Gabriel Andres Tafur; Pinheiro, Aimara da Costa; Maciel, Talles Eduardo Ferreira; Silva-Júnior, Abelardo; Bressan, Gustavo Costa; Almeida, Márcia Rogéria; et al.Visceral leishmaniasis is an important tropical disease, and Leishmania infantum chagasi (synonym of Leishmania infantum) is the main pathogenic agent of visceral leishmaniasis in the New World. Recently, ecto-nucleoside triphosphate diphosphohydrolases (E-NTPDases) were identified as enablers of infection and virulence factors in many pathogens. Two putative E-NTPDases (∼70 kDa and ∼45 kDa) have been found in the L. infantum genome. Here, we studied the ∼45 kDa E-NTPDase from L. infantum chagasi to describe its natural occurrence, biochemical characteristics and influence on macrophage infection. We used live L. infantum chagasi to demonstrate its natural ecto-nucleotidase activity. We then isolated, cloned and expressed recombinant rLicNTPDase-2 in bacterial system. The recombinant rLicNTPDase-2 hydrolyzed a wide variety of triphosphate and diphosphate nucleotides (GTP> GDP = UDP> ADP> UTP = ATP) in the presence of calcium or magnesium. In addition, rLicNTPDase-2 showed stable activity over a pH range of 6.0 to 9.0 and was partially inhibited by ARL67156 and suramin. Microscopic analyses revealed the presence of this protein on cell surfaces, vesicles, flagellae, flagellar pockets, kinetoplasts, mitochondria and nuclei. The blockade of E-NTPDases using antibodies and competition led to lower levels of parasite adhesion and infection of macrophages. Furthermore, immunohistochemistry showed the expression of E-NTPDases in amastigotes in the lymph nodes of naturally infected dogs from an area of endemic visceral leishmaniasis. In this work, we cloned, expressed and characterized the NTPDase-2 from L. infantum chagasi and demonstrated that it functions as a genuine enzyme from the E-NTPDase/CD39 family. We showed that E-NTPDases are present on the surface of promastigotes and in other intracellular locations. We showed, for the first time, the broad expression of LicNTPDases in naturally infected dogs. Additionally, the blockade of NTPDases led to lower levels of in vitro adhesion and infection, suggesting that these proteins are possible targets for rational drug design.Item Potential antileukemia effect and structural analyses of SRPK inhibition by N-(2- (Piperidin-1-yl)-5-(Trifluoromethyl)Phenyl) isonicotinamide (SRPIN340)(Plos One, 2014-04-08) Siqueira, Raoni Pais; Barbosa, Éverton de Almeida Alves; Polêto, Marcelo Depólo; Righetto, Germanna Lima; Seraphim, Thiago Vargas; Salgado, Rafael Locatelli; Ferreira, Joana Gasperazzo; Oliveira, Leandro Licursi de; Laranjeira, Angelo Brunelli Albertoni; Almeida, Márcia Rogéria; Fietto, Juliana Lopes Rangel; Kobarg, Jörg; Oliveira, Eduardo Basílio de; Teixeira, Robson Ricardo; Borges, Júlio César; Silva Júnior, Abelardo; Bressan, Gustavo Costa; et al.Dysregulation of pre-mRNA splicing machinery activity has been related to the biogenesis of several diseases. The serine/arginine-rich protein kinase family (SRPKs) plays a critical role in regulating pre-mRNA splicing events through the extensive phosphorylation of splicing factors from the family of serine/arginine-rich proteins (SR proteins). Previous investigations have described the overexpression of SRPK1 and SRPK2 in leukemia and other cancer types, suggesting that they would be useful targets for developing novel antitumor strategies. Herein, we evaluated the effect of selective pharmacological SRPK inhibition by N-(2-(piperidin-1-yl)-5-(trifluoromethyl)phenyl)isonicotinamide (SRPIN340) on the viability of lymphoid and myeloid leukemia cell lines. Along with significant cytotoxic activity, the effect of treatments in regulating the phosphorylation of the SR protein family and in altering the expression of MAP2K1, MAP2K2, VEGF and FAS genes were also assessed. Furthermore, we found that pharmacological inhibition of SRPKs can trigger early and late events of apoptosis. Finally, intrinsic tryptophan fluorescence emission, molecular docking and molecular dynamics were analyzed to gain structural information on the SRPK/SRPIN340 complex. These data suggest that SRPK pharmacological inhibition should be considered as an alternative therapeutic strategy for fighting leukemias. Moreover, the obtained SRPK-ligand interaction data provide useful structural information to guide further medicinal chemistry efforts towards the development of novel drug candidates.Item Production, characterization and foamability of α-lactalbumin/glycomacropeptide supramolecular structures(Food Research International, 2014-06-17) Diniz, Renata Silva; Coimbra, Jane Sélia dos Reis; Teixeira, Álvaro Vianna Novaes de Carvalho; Costa, Angélica Ribeiro da; Santos, Igor José Boggione; Bressan, Gustavo Costa; Rodrigues, Antonio Manuel da Cruz; Silva, Luiza Helena Meller daThe study of protein interactions has generated great interest in the food industry. Therefore, research on new supramolecular structures shows promise. Supramolecular structures of the whey proteins α-lactalbumin and glycomacropeptide were produced under varying heat treatments (25 to 75 °C) and acidic conditions (pH 3.5to 6.5). Isothermal titration calorimetry experiments showed protein interactions and demonstrated that this is an enthalpically driven process. Supramolecular protein structures in aqueous solutions were characterized by circular dichroism and intrinsic fluorescence spectroscopy. Additional photon correlation spectroscopy experiments showed that the size distribution of the structures ranged from 4 to 3545 nm among the different conditions. At higher temperatures, lower pH increased particle size. The foamability of the supramolecular protein structures was evaluated. Analysis of variance and analysis of regression for foaming properties indicated that the two-factor interactions between pH and temperature exhibited a significant effect on the volume and stability of the foam.Item Retrospective detection and genetic characterization of Porcine circovirus 3 (pcv3) strains identified between 2006 and 2007 in Brazil(Viruses, 2019-03) Saraiva, Giuliana Loreto; Vidigal, Pedro Marcus Pereira; Assao, Viviane Sisdelli; Fajardo, Murilo Leone Miranda; Loreto, Alerrandra Nunes Saraiva; Fietto, Juliana Lopes Rangel; Bressan, Gustavo Costa; Lobato, Zélia Inês Portela; Almeida, Márcia Rogéria de; Silva-Júnior, AbelardoPorcine circovirus 3 (PCV3) is an emerging virus that was first identified in the United States in 2016. Since its first detection, PCV3 has already been found in America, Asia, and Europe. Although PCV3 has already been described in Brazil, knowledge of its detection and sequence variation before 2016 is limited, as well as its distribution in the main swine producing regions of Brazil. In this study, 67 porcine clinical samples collected from nine states in Brazil between 2006 and 2007 were analyzed for PCV3 infection by PCR. Results showed that 47.8% of the samples were PCV3 positive, across all nine states. Of the PCV3-positive samples, 37.5% were also positive for PCV2. Interestingly, no clinical signs were associated with samples that were detected singularly with PCV3 infection. Moreover, the positive PCV3 rate in healthy pigs was higher (29.8%) than that found in unhealthy pigs (17.9%), suggesting that most pigs could live with PCV3 infection without any clinical sign in the analyzed samples. Nucleotide sequence analysis showed that PCV3 strains obtained in this study shared 94.44% to 99.83% sequence identity at the open reading frame 2 (ORF2) gene level with available strains from different countries. PCV3 Brazilian sequences collected in 2006 and 2007 shared 97.94% to 99.62% identity with the strains obtained in 2016. The results of neutrality and selective pressure tests indicated that the PCV3 Cap protein seems unable to tolerate high levels of variation on its sequence. Phylogenetic analysis grouped the Brazilian strains in PCV3a and PCV3b genotypes clusters, both including strains collected in America, Asia, and Europe. Taking the results together, multiple events of introduction of PCV3 may have occurred in Brazil, and Brazilian PCV3 strains may show genetic stability over the past 10 years.Item Síntese e avaliação da atividade citotóxica de derivados do eugenol contendo núcleos 1,2,3-triazólicos(Química Nova, 2018-05) Gazolla, Poliana Aparecida Rodrigues; Teixeira, Róbson Ricardo; Silva, Adalberto Manoel da; Vaz, Boniek Gontijo; Vasconcelos, Géssica Adriana; Siqueira, Raoni Pais; Gonçalves, Victor Hugo Sousa; Pereira, Higor Sette; Bressan, Gustavo CostaEugenol is an aromatic compound found in several plant species. It presents important biological activities including cytotoxicity. In this paper, it is described the synthesis and the evaluation of the cytotoxic activity of eugenol derivatives bearing 1,2,3-triazole functionalities. Eugenol, extracted via hydrodistillation from dried flower buds of Eugenia caryophyllata (=Syzygium aromaticum), was submitted to alkylation reactions to afford two terminal alkynes in good yields. The key reaction involved in the preparation of eugenol derivatives corresponded to the Copper(I)-catalyzed Azide-Alkyne Cycloaddition (CuAAC), between alkynylated eugenol derivatives and different benzyl azides. The evaluation of the cytotoxicity of twenty seven synthesized derivatives against HL60 leukemia cell line revealed that at 100 µmol L-1, five of them, namely 4-((4-allyl-2-methoxyphenoxy)methyl)-1-(3-bromobenzyl)-1H-1,2,3-triazole (6n), 4-(3-(4-allyl-2-methoxyphenoxy)propyl)-1-benzyl-1H-1,2,3-triazole (7a), 4-(3-(4-allyl-2-methoxyphenoxy)propyl)-1-(4-chlorobenzyl)-1H-1,2,3-triazole (7c), 4-(3-(4-allyl-2-methoxyphenoxy)propyl)-1-(4-iodobenzyl)-1H-1,2,3-triazole (7e) and 4-(3-(4-allyl-2-methoxyphenoxy)propyl)-1-(3-bromobenzyl)-1H-1,2,3-triazole (7m), were capable of significantly decreasing cell viability. These most active triazolic derivatives were also evaluated against B16F10 melanoma and Nalm6 leukemia cell lines. While only compound 7a was active against the former, compounds 6n, 7a, and 7m displayed activity against the latter. Derivative 7a was active against all cell lines. It is believed that eugenol derivatives bearing triazole functionalities may represent a scaffold to be explored toward the development of new agents against cancer.Item Splicing regulators and their roles in cancer biology and therapy(BioMed Research International, 2015-04-01) Silva, Maria Roméria da; Moreira, Gabriela Alves; Silva, Ronni Anderson Gonçalves da; Barbosa, Éverton de Almeida Alves; Siqueira, Raoni Pais; Teixera, Róbson Ricardo; Almeida, Márcia Rogéria; Silva Júnior, Abelardo; Fietto, Juliana Lopes Rangel; Bressan, Gustavo CostaAlternative splicing allows cells to expand the encoding potential of their genomes. In this elegant mechanism, a single gene can yield protein isoforms with even antagonistic functions depending on the cellular physiological context. Alterations in splicing regulatory factors activity in cancer cells, however, can generate an abnormal protein expression pattern that promotes growth, survival, and other processes, which are relevant to tumor biology. In this review, we discuss dysregulated alternative splicing events and regulatory factors that impact pathways related to cancer. The SR proteins and their regulatory kinases SRPKs and CLKs have been frequently found altered in tumors and are examined in more detail. Finally, perspectives that support splicing machinery as target for the development of novel anticancer therapies are discussed.Item Synthesis and antimetastatic activity evaluation of cinnamic acid derivatives containing 1,2,3-triazolic portions(Toxicology in Vitro, 2018-12) Lima, Graziela Domingues de Almeida; Rodrigues, Michelle Peixoto; Moreira, Gabriela Alves; Mendes, Tiago Antônio de Oliveira; Siqueira, Raoni Pais; Silva, Adalberto Manoel da; Vaz, Boniek Gontijo; Fietto, Juliana Lopes Rangel; Bressan, Gustavo Costa; Teixeira, Róbson Ricardo; Machado-Neves, MarianaIt is herein described the preparation and evaluation of antimetastatic activity of twenty-six cinnamic acid derivatives containing 1,2,3-triazolic portions. The compounds were prepared using as the key step the Copper(I)-catalyzed azide (A)-alkyne (A) cycloaddition (C) (CuAAC reaction), also known as click reaction, between alkynylated cinnamic acid derivatives and different benzyl azides. The reactions were carried in CH2Cl2/H2O (1:1 v/v) at room temperature, and the triazole derivatives were obtained in yields ranging from 73%99%. Reaction times varied from 5 to 40 min. The identity of the synthesized compounds was confirmed by IR and NMR (1H and 13C) spectroscopic techniques. They were then submitted to in vitro bioassays to investigate how they act over metastatic behavior of murine melanoma. The most potent compound, namely 3-(1-benzyl-1H-1,2,3-triazol-4-yl)propyl cinnamate (9a), showed significant antimetastatic and antiproliferative activities against B16-F10 cells. In addition, gelatin zymography and molecular docking analyses pointed to the fact that this compound has potential to interact with matrix metalloproteinase 9 (MMP-9) and MMP-2, which are directly involved in melanoma progression. Therefore, these findings suggest that cinnamic acid derivatives containing 1,2,3-triazolic portions may have potential for development of novel candidates for controlling malignant metastatic melanoma.Item Synthesis and antiproliferative activity of C-3 functionalized Isobenzofuran-1(3H)-ones(Molecules, 2013-02-01) Teixeira, Róbson Ricardo; Bressan, Gustavo Costa; Pereira, Wagner Luiz; Ferreira, Joana Gasperazzo; Oliveira, Fabrício Marques de; Thomaz, Deborah CamposA series of thirteen C-3 functionalized isobenzofuran-1(3H)-ones (phtalides) was synthesized via condensation, aromatization, and acetylation reactions. NMR (one and two dimensional experiments), IR, and mass spectrometry analysis allowed confirmation of the identity of the synthesized compounds. The substances were submitted to in vitro bioassays against U937 (lymphoma) and K562 (myeloid leukemia) cancer cell lines using the MTT cytotoxicity assay. Some derivatives inhibited 90% of cell viability at 100 µM. Also, two phtalides presented biological activity superior than that of etoposide (VP16), a commercial drug used as a positive control in the assays. In silico drug properties of the evaluated compounds were calculated and the results are discussed.Item Synthesis, molecular properties prediction and cytotoxic screening of 3-(2-aryl-2-oxoethyl)isobenzofuran-1(3H)-ones(Elsevier Bioorganic & Medicinal Chemistry Letters, 2016-04-25) Maia, Angélica Faleiros da Silva; Siqueira, Raoni Pais; Oliveira, Fabrício Marques de; Ferreira, Joana Gasperazzo; Silva, Silma Francielle da; Caiuby, Clarice Alves Dale; Oliveira, Leandro Licursi de; Paula, Sérgio Oliveira de; Souza, Rafael Aparecido Carvalho; Guilardi, Silvana; Bressan, Gustavo Costa; Teixeira, Róbson RicardoIn the present investigation, a collection of nineteen 3-(2-aryl-2-oxoethyl)isobenzofuran-1(3H)-ones was synthesized and screened for their cytotoxic activity against a panel of three leukemia cancer cell lines. The compounds were prepared via ZrOCl2·8H2O catalyzed condensation reactions between phthalaldehydic acid and different acetophenones. The reactions were carried out free of solvent and the isobenzofuran-1(3H)-ones were obtained in good yields (80–92%). The identities of the synthesized compounds were confirmed upon IR and NMR (1H and 13C) spectroscopy as well as high resolution mass spectrometry analyses. Structures of compounds 1, 4 and 16 were also investigated by X-ray analysis. The synthesized compounds were submitted to in vitro bioassays against HL-60, K562 and NALM6 cancer cell lines using MTT cytotoxicity assay. After 48 h of treatment, twelve derivatives were able to reduce cell viability and presented IC50 values equal to or below 20 μmol L−1 against at least one of the evaluated lineages. The most active compound corresponded to 3-(3-methylphenyl-2-oxoethyl)isobenzofuran-1(3H)-one (18) (IC50 values obtained for HL-60, K562 and NALM6 were, respectively, 13.5 μmol L−1, 8.83 μmol L−1, and 5.24 μmol L−1). In addition, compound 18 was capable of triggering apoptosis on NALM6 cells. All isobenzofuranones herein evaluated did not present cytotoxicity on peripheral blood mononuclear cells (PBMC), suggesting selective cytotoxic effect on leukemic cells. A computational study allowed prediction of pharmacokinetics and drug-likeness properties of the synthesized compounds. DFT calculations were performed to obtain the energy values of HOMO, LUMO, and dipole moments of isobenzofuranones.Item Synthesis, theoretical studies, and effect on the photosynthetic electron transport of trifluoromethyl arylamides(Pest Management Science, 2017-05-25) Teixeira, Róbson Ricardo; Barros, Marcus Vinícius de Andrade; Bressan, Gustavo Costa; Siqueira, Raoni Pais; Santos, Fabíola Suelen dos; Bertazzini, Michele; Kiralj, Rudolf; Ferreira, Márcia Miguel Castro; Forlani, GiuseppeThe photosynthetic apparatus is targeted by various herbicides, including several amides such as diuron and linuron. Considering the need for the discovery of new active ingredients to cope with weed resistance, the synthesis of a series of trifluoromethyl aryl amides is herein described whose inhibitory properties were assessed in vitro on the photosynthetic electron transport chain, and in vivo on the growth of a model cyanobacterial strain. Theoretical studies were also carried out. Starting with 1‐fluoro‐2‐nitro‐4‐(trifluoromethyl) benzene, the preparation of the amides was achieved via a three‐step sequence, namely nucleophilic aromatic substitution, reduction with SnCl2/HCl, and acylation reactions. The measurement of ferricyanide reduction by functionally intact spinach chloroplasts showed that several derivatives are capable of inhibiting the photosynthetic apparatus. The most active amides presented IC50 values close to 1 μmol L−1, and showed the presence of a 4‐bromophenyl group as a common structural feature. The addition of these brominated amides to the culture medium of a model cyanobacterial strain, Synechococcus elongatus PCC 6301, caused various degrees of growth inhibition. Theoretical studies (molecular modeling and quantitative structure–activity relationship) of all amides and their comparison with some known herbicides confirmed these experimental findings and provided more in‐depth information about the possible molecular target of these compounds. Trifluoromethyl amides herein described, which were shown to act at the PSII level, may represent a novel scaffold to be exploited aiming at the development of new active ingredients for weed control.Item Trifluoromethyl arylamides with antileukemia effect and intracellular inhibitory activity over serine/arginine-rich protein kinases (SRPKs)(European Journal of Medicinal Chemistry, 2017-03-31) Siqueira, Raoni Pais; Barros, Marcus Vinícius de Andrade; Barbosa, Éverton de Almeida Alves; Onofre, Thiago Souza; Gonçalves, Victor Hugo Sousa; Pereira, Higor Sette; Silva Júnior, Abelardo; Oliveira, Leandro Licursi de; Almeida, Márcia Rogéria; Fietto, Juliana Lopes Rangel; Teixeira, Róbson Ricardo; Bressan, Gustavo CostaThe serine/arginine-rich protein kinases (SRPKs) have frequently been found with altered activity in a number of cancers, suggesting they could serve as potential therapeutic targets in oncology. Here we describe the synthesis of a series of twenty-two trifluoromethyl arylamides based on the known SRPKs inhibitor N-(2-(piperidin-1-yl)-5-(trifluoromethyl)phenyl)isonicotinamide (SRPIN340) and the evaluation of their antileukemia effects. Some derivatives presented superior cytotoxic effects against myeloid and lymphoid leukemia cell lines compared to SRPIN340. In particular, compounds 24, 30, and 36 presented IC50 values ranging between 6.0 and 35.7 μM. In addition, these three compounds were able to trigger apoptosis and autophagy, and to exhibit synergistic effects with the chemotherapeutic agent vincristine. Furthermore, compound 30 was more efficient than SRPIN340 in impairing the intracellular phosphorylation status of SR proteins as well as the expression of MAP2K1, MAP2K2, VEGF, and RON oncogenic isoforms. Therefore, novel compounds with increased intracellular effects against SRPK activity were obtained, contributing to medicinal chemistry efforts towards the development of new anticancer agents.Item Trypanosoma cruzi nucleoside triphosphate diphosphohydrolase 1 (TcNTPDase-1) biochemical characterization, immunolocalization and possible role in host cell adhesion(Acta Tropica, 2013-11-19) Mariotini-Moura, Christiane; Bastos, Matheus Silva e; Castro, Felipe Freitas de; Trindade, Mellina Lanna; Vasconcellos, Raphael de Souza; Neves-do-Valle, Myrian Augusta Araújo; Moreira, Bernardo Pereira; Santos, Ramon de Freitas; Oliveira, Claudia Miranda de; Cunha, Luana Celina Seraphim; Souto, Xênia Macedo; Bressan, Gustavo Costa; Silva-Júnior, Abelardo; Baqui, Munira Muhammad Abdel; Bahia, Maria Terezinha; Almeida, Márcia Rogéria de; Meyer-Fernandes, José Roberto; Fietto, Juliana Lopes RangelPrevious work has suggested that Trypanosoma cruzi diphosphohydrolase 1 (TcNTPDase-1) may be involved in the infection of mammalian cells and serve as a potential target for rational drug design. In this work, we produced recombinant TcNTPDase-1 and evaluated its nucleotidase activity, cellular localization and role in parasite adhesion to mammalian host cells. TcNTPDase-1 was able to utilize a broad range of triphosphate and diphosphate nucleosides. The enzyme's Km for ATP (0.096 mM) suggested a capability to influence the host's ATP-dependent purinergic signaling. The use of specific polyclonal antibodies allowed us to confirm the presence of TcNTPDase-1 at the surface of parasites by confocal and electron microscopy. In addition, electron microscopy revealed that TcNTPDase-1 was also found in the flagellum, flagellum insertion region, kinetoplast, nucleus and intracellular vesicles. The presence of this enzyme in the flagellum insertion region and vesicles suggests that it may have a role in nutrient acquisition, and the widespread distribution of TcNTPDase-1 within the parasite suggests that it may be involved in other biological process. Adhesion assays using anti-TcNTPDase-1 polyclonal antibodies as a blocker or purified recombinant TcNTPDase-1 as a competitor revealed that the enzyme has a role in parasite–host cell adhesion. These data open new frontiers to future studies on this specific parasite–host interaction and other unknown functions of TcNTPDase-1 related to its ubiquitous localization.Item Utilization of phage display to identify antigenic regions in the PCV2 capsid protein for the evaluation of serological responses in mice and pigs(Archives of Virology, 2018-07) Santos, Marcus Rebouças; Assao, Viviane Sisdelli; Salgado, Rafael Locatelli; Fietto, Juliana Lopes Rangel; Bressan, Gustavo Costa; Almeida, Márcia Rogéria de; Goulart, Luíz Ricardo; Silva-Júnior, Abelardo; Santos, Fabiana de Almeida Araújo; Carneiro, Ana Paula; Lobato, Zelia Inês Portela; Veira, Carlos UeiraPorcine circovirus 2 (PCV2) is associated with a series of swine diseases. There is a great interest in improving our understanding of the immunology of PCV2, especially the properties of the viral capsid protein Cap-PCV2 and how they relate to the immunogenicity of the virus and the subsequent development of vaccines. Phage display screening has been widely used to study binding affinities for target proteins. The aim of this study was to use phage display screening to identify antigenic peptides in the PCV2 capsid protein. After the selection of peptides, five of them presented similarity to sequences found in cap-PCV2, and four peptides were synthesized and used for immunization in mice: 51–CTFGYTIKRTVT-62 (PS14), 127-CDNFVTKATALTY-138 (PS34), 164-CKPVLDSTIDY-173 (PC12), and 79-CFLPPGGGSNT-88 (PF1). Inoculation with the PC12 peptide led to the highest production of antibodies. Furthermore, we used the PC12 peptide as an antigen to examine the humoral response of swine serum by ELISA. The sensitivity and specificity of this assay was 88.9% and 92.85%, respectively. Altogether, characterization of immunogenic epitopes in the capsid protein of PCV2 may contribute to the improvement of vaccines and diagnostics.