RESUMO
BACKGROUND: Dengue virus (DENV) is a Flaviviridae member classified into four antigenically distinct serotypes (DENV 1, 2, 3, and 4) and further subdivided genotypes. DENV3 is subdivided into four or five genotypes, depending on the classification adopted. Despite their high genetic proximity, as revealed by phylogenetic complete polyprotein analysis, DENV3 MG-20 and DENV3 PV_BR showed different neurovirulence in mice models. Our group identified six amino acid mutations in protein E, including the E62K and E123Q, which may affect interactions of hydrophobic clusters on domain II, thus leading to the observed differences in the studied viruses. METHODS: Human glioblastoma cells (U251) derived from a malignant glioblastoma tumor by explant technique were infected by the DENV3 GIL1 isolates DENV3 MG-20 and DENV3 PV_BR and analyzed by plaque assays and titration, optical, immunofluorescence, and transmission electronic microscopy. RESULTS: The two isolates showed different cytopathic effects (CPE) and fusogenic patterns, further confirmed by indirect immunofluorescence. Transmission electron microscopy revealed intense cytopathic effects in DENV3 MG-20 infected U251 cells, displaying endoplasmic reticulum hypertrophy and turgid vesicles with proteins and multiple viruses, distinct from DENV3 PV_BR infected cells. It is hypothesized that the different amino acids in the DENV3 MG-20 isolate are related to an increased membrane fusion ability in viral infection, thus facilitating immune system evasion and increased chances of central nervous system cell infection. CONCLUSION: These results emphasize the biological differences between the isolates, which could be a critical factor in host-virus interaction and severe dengue development. Our study presents comparative results of highly similar isolates with the potential to generate more subsidies for a deeper understanding of the DENV pathogenesis. The neurotropism of the isolate DENV3 MG-20 (belonging to the DENV3 GI L1 genotype) showing infection of nervous system cells (U251) could contribute to understanding neurological dengue disease.
Assuntos
Vírus da Dengue , Glioblastoma , Humanos , Animais , Camundongos , Vírus da Dengue/genética , Filogenia , Aminoácidos , Genótipo , Células GigantesRESUMO
Gliomas are responsible for more than 60% of all primary brain tumors. Glioblastoma multiforme (GBM), a grade IV tumor (WHO), is one of the most frequent and malignant gliomas. Despite two decades of advances in the discovery of new markers for GBM, the chemotherapy of choice falls to temozolomide after surgery and radiotherapy, which are not enough to increase the survival of patients to more than 15 months. It is urgent to discover new anti-glioma compounds. Many compounds derived from natural products have been used in the development of anti-tumor drugs. In this work, we have screened six low molecular weight sesquiterpene lactones, isolated from Eremanthus spp., and studied their function as anti-proliferative agents against GBM strains. We demonstrated that two of them, goyazensolide and lychnofolide, were effective in reducing cell viability, preventing the formation of anchorage-dependent colony and were able to pass through a mimetic blood-brain barrier making them candidates for glioma therapy, being more potent than temozolomide, according to in vitro assays for the cell lines tested. Proteomic analysis revealed a number of altered proteins involved in glycolytic metabolism and cellular catabolism.
Assuntos
Lactonas/farmacologia , Vernonia/metabolismo , Antineoplásicos/farmacologia , Asteraceae , Barreira Hematoencefálica/metabolismo , Neoplasias Encefálicas/metabolismo , Brasil , Hidrocarbonetos Aromáticos com Pontes/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Furanos/farmacologia , Glioblastoma/tratamento farmacológico , Glioblastoma/metabolismo , Glioma/metabolismo , Humanos , Lactonas/metabolismo , Extratos Vegetais/farmacologia , Sesquiterpenos/farmacologia , Sesterterpenos/farmacologia , Vernonia/fisiologiaRESUMO
BACKGROUND: One of the possible ways of improving the activity and selectivity profile of anticancer agents is to design drug carrier systems employing nanomolecules. Calix[4]arene derivatives and chlorambucil and ibuprofen are important compounds that exhibit interesting anticancer properties. OBJECTIVE: The objective of this article is the synthesis of new calix[4]arene-derivative conjugates of chlorambucil or ibuprofen with potential anticancer activity. METHODS: Cytotoxicity assays were determined using the protein-binding dye sulforhodamine B (SRB) in microculture to measure cell growth as described [19, 20]. Conjugates of chlorambucil and resorcinarene-dendrimers were prepared in 2% DMSO and added into the culture medium immediately before use. Control cells were treated with 2% DMSO. RESULTS: Thus, calix[4]arene-derivative conjugates of chlorambucil or ibuprofen showed good stability of the chemical link between drug and spacer. Evaluation of the cytotoxicity of the calix[4]arene chlorambucil or ibuprofen conjugates employing a sulforhodamine B (SRB) assay in K-562 (human chronic myelogenous leukemia cells) and U-251 (human glioblastoma cells) demonstrated that the conjugate was more potent as an antiproliferative agent than free chlorambucil and ibuprofen. The conjugates did not show any activity against the COS-7 African green monkey kidney fibroblast cell line. CONCLUSION: In the paper, we report the synthesis and spectroscopic analyses of new calix[4]arene derivative conjugates of chlorambucil or ibuprofen. Cytotoxicity assays revealed that at 10 µM, the conjugates were very active against K-562 (human chronic myelogenous leukemia cells) and U- 251 (human glioblastoma cells) cancer cells' proliferation. In order to explain the molecular mechanisms involved in the anticancer activity of calix[4]arene chlorambucil or ibuprofen conjugates, our research will be continued.
Assuntos
Antineoplásicos/farmacologia , Calixarenos/farmacologia , Clorambucila/farmacologia , Ibuprofeno/farmacologia , Fenóis/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Calixarenos/química , Proliferação de Células/efeitos dos fármacos , Clorambucila/síntese química , Clorambucila/química , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Ibuprofeno/síntese química , Ibuprofeno/química , Estrutura Molecular , Fenóis/química , Células Tumorais CultivadasRESUMO
Twelve multi-functional pyrrolizidinones, indolizidinones and pyrroliazepinones were prepared from formal aza-[3 + 2] and aza-[3 + 3] cycloadditions of five- to seven-membered heterocyclic enaminones as diverse ambident electrophiles. The antitumor activity of these alkaloid-like compounds was investigated through an initial screening performed on human glioblastoma multiform (GBM) cell lines (GL-15, U251), on murine glioma cells line (C6) and on normal glial cells. Of the compounds tested, the new pyrrolo[1,2a]azepinone, [ethyl (3-oxo-1,2-diphenyl-6,7,8,9-tetrahydro-3H-pyrrolo[1,2a]azepin-9a(5H)-yl)acetate] or (Compound-13) exhibited selective cytotoxic effects on GBM-temozolomide resistant cells. Compound-13 exerted dose-dependent cytotoxic activity by promoting arrest of cells in the G0/G1 phase of the cell cycle in the first 24 h. The apoptotic effect observed was in a time-dependent manner. Anti-migratory effect promoted by the treatment with compound-13 was also observed. Moreover, healthy mixed glial cell cultures from rat brain exhibited no cytotoxicity effect upon exposure to compound-13. Thus, the present study paves the way for the use of compound-13 as novel antitumor scaffold candidate for glioma cell therapy.
Assuntos
Antineoplásicos/farmacologia , Compostos Azabicíclicos/farmacologia , Neoplasias Encefálicas/tratamento farmacológico , Glioblastoma/tratamento farmacológico , Animais , Apoptose/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Desenho de Fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Humanos , Ratos Wistar , Temozolomida/farmacologia , Cicatrização/efeitos dos fármacosRESUMO
A new source of pectin with a cytotoxic effect on glioblastoma cells is presented. A homogeneous GWP-FP-S fraction (Mw of 29,170â¯gâ¯mol-1) was obtained by fractionating the crude pectin extract (GW) from Campomanesia xanthocarpa pulp. According to the monosaccharide composition, the GWP-FP-S was composed of galacturonic acid (58.8%), arabinose (28.5%), galactose (11.3%) and rhamnose (1.1%), comprising 57.7% of homogalacturonans (HG) and 42.0% of type I rhamnogalacturonans (RG-I). These structures were characterized by chromatographic and spectroscopic methods; GW and GWP-FP-S fractions were evaluated by MTT and crystal violet assays for their cytotoxic effects. Both fractions induced cytotoxicity (15.55-37.65%) with concomitant increase in the cellular ROS levels in human glioblastoma cells at 25-400⯵g mL-1, after 48â¯h of treatment, whereas no cytotoxicity was observed for normal NIH 3T3 cells. This is the first report of in vitro bioactivity and the first investigation of the antitumor potential of gabiroba pectins.
Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Glioblastoma/patologia , Pectinas/química , Pectinas/farmacologia , Pimenta/química , Antineoplásicos/isolamento & purificação , Linhagem Celular Tumoral , Humanos , Espaço Intracelular/efeitos dos fármacos , Espaço Intracelular/metabolismo , Monossacarídeos/análise , Pectinas/isolamento & purificação , Espécies Reativas de Oxigênio/metabolismoRESUMO
The widely accepted resazurin-based assay can be used, prior to in vivo studies, as an inexpensive method to determine cytotoxicity. The aim of this study was to evaluate and standardize the assay conditions for oral squamous cancer cell (OSCC) and glioblastoma (U87-MG) lines by UV-vis spectroscopy. The cells were treated with 25 µgmL-1 of resazurin sodium salt and then incubated for 4 h, 6 h, and 6.5 h. All absorbance measurements were carried out at 21 ± 1 °C on a spectrophotometer with a microplate reader. After 4-hs of incubation, resazurin was completely reduced by OSCC cells, as demonstrated by the suppression of the absorbance at 380 nm. However, the U87-MG cells needed 6.5 h of incubation to demonstrate the same behavior. The Statistical analysis did not indicate significant differences between the OSCC and U87-MG cell lines' viability after 4 and 6.5 h respectively. We concluded that spectroscopic analysis is an efficient method for the standardization of the resazurin assay. In addition, without the implementation of suitable protocols, there could be an increase in the chance of errors or false positives or negatives that would reduce the usefulness of the data.
Assuntos
Carcinoma de Células Escamosas/metabolismo , Glioblastoma/metabolismo , Neoplasias Bucais/metabolismo , Oxazinas/química , Xantenos/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Humanos , Análise Espectral/métodosRESUMO
BACKGROUND AND AIMS: Evidence suggests that quantity and quality of dietary polyunsaturated fatty acids (PUFAs) play a role in the development of cancer. However, the mechanisms involved in this interaction(s) are not clear. Endocannabinoids are lipid metabolites known to have growth modulatory actions. We studied the effect of supplementation with PUFAs ω-6 and ω-3 (essential fatty acids, EFAs), saturated and monounsaturated fatty acids (non-EFAs) on the growth of tumor cells and modifications in their endocannabinoid content. METHODS: Cell cultures of human glioblastoma (T98G) and breast cancer (MCF7) were supplemented with 50 or 100 mmol EFAs and non-EFAs for 72 h. Cell proliferation was then determined by MTT, anandamide (AEA) levels by HPLC, total fatty acids profiles by GLC, CB1 receptor expression by WB and FAAH activity by spectrophotometric method. RESULTS: Fatty acids profile reflected the incorporation of the lipids supplemented in each assay. Arachidonic acid (EFA ω-6) supplementation increased AEA levels and inhibited the growth of T98G, whereas palmitic acid (non-EFA) enhanced their proliferation. In breast cancer (MCF7) cells, eicosapentaenoic acid (EFA ω-3) reduced and oleic acid (non-EFA) enhanced their proliferation. CB1 expression was higher in T98G and no differences were observed in FAAH activity. CONCLUSIONS: The growth of tumor cells can be differentially modulated by fatty acids and, at least in part, can be attributed to their ability to act on the components of the endocannabinoid system.