RESUMO
Stromal-interaction molecule 1 (STIM1)-mediated store-operated Ca2+ entry (SOCE) plays a key role in mediating cardiomyocyte hypertrophy, both in vitro and in vivo. Moreover, there is growing support for the contribution of SOCE to the Ca2+ overload associated with ischemia/reperfusion injury. Therefore, STIM1 inhibition is proposed as a novel target for controlling both hypertrophy and ischemia/reperfusion-induced Ca2+ overload. Our aim was to evaluate the effect of ML9, a STIM1 inhibitor, on cardiomyocyte viability. ML9 was found to induce cell death in cultured neonatal rat cardiomyocytes. Caspase-3 activation, apoptotic index and release of the necrosis marker lactate dehydrogenase to the extracellular medium were evaluated. ML9-induced cardiomyocyte death was not associated with increased intracellular ROS or decreased ATP levels. Moreover, treatment with ML9 significantly increased levels of the autophagy marker LC3-II, without altering Beclin1 or p62 protein levels. However, treatment with ML9 followed by bafilomycin-A1 did not produce further increases in LC3-II content. Furthermore, treatment with ML9 resulted in decreased LysoTracker® Green staining. Collectively, these data suggest that ML9-induced cardiomyocyte death is triggered by a ML9-dependent disruption of autophagic flux due to lysosomal dysfunction.
Assuntos
Autofagia/efeitos dos fármacos , Azepinas/toxicidade , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Molécula 1 de Interação Estromal/antagonistas & inibidores , Animais , Animais Recém-Nascidos , Apoptose/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Células Cultivadas , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Necrose/induzido quimicamente , Necrose/patologia , Ratos , Espécies Reativas de Oxigênio/metabolismoRESUMO
PURPOSE: The aim of this study was to compare the cellular susceptibility patterns and morphologic changes in the corneal endothelium associated with the use of fourth-generation fluoroquinolones. METHOD: Endothelial susceptibility was assessed through intracameral injection of besifloxacin, gatifloxacin, and moxifloxacin. Human umbilical vein endothelial cells (HUVECs) were used as the standard cellular lineage to assess the quantitative toxicity of each antibiotic solution. Qualitative changes in the morphologic character of the corneal structure and the endothelial layer were generated using a combination of ex vivo and in vivo assays. Experimental assays were conducted in triplicate, and the results were statistically analyzed. RESULTS: At 1 hour of exposure, all HUVECs exposed to antibiotics showed viability above 85%, after 3 hours of exposure to besifloxacin, gatifloxacin, and moxifloxacin, the percentages of viable cells were 68.3 ± 4.0 (P < 0.001), 90.7 ± 4.2 (P < 0.05), and 93.3 ± 1.5 (P > 0.05), respectively. All fluoroquinolones tested showed toxicity to HUVECs, resulting in significant (P < 0.001) loss of cellular viability after 24 hours of drug exposure. Giant endothelial cells were observed in animals treated with the 3 fluoroquinolones in contrast to the absence of these abnormal cells in the untreated group. Early cellular detachment was seen in the endothelial layer after exposure to gatifloxacin and moxifloxacin. CONCLUSIONS: We concluded that injection of fourth-generation fluoroquinolones in the aqueous humor did not adversely affect the corneal endothelium. However, these results suggested that prophylactic intracameral injection of besifloxacin, gatifloxacin, or moxifloxacin, if needed, should be administered as a last therapeutic resource in clinical practice, with careful and constant monitoring of corneal endothelium.
Assuntos
Antibacterianos/toxicidade , Azepinas/toxicidade , Endotélio Corneano/efeitos dos fármacos , Fluoroquinolonas/toxicidade , Animais , Humor Aquoso/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Endotélio Corneano/patologia , Gatifloxacina , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Injeções Intraoculares , Masculino , Moxifloxacina , Soluções Oftálmicas , Coelhos , Inibidores da Topoisomerase II/toxicidadeRESUMO
A series of new racemic 4-amino-6-aryl-8-(1,3-benzodioxol-5-yl)-8,9-dihydro-7H-pyrimido[4,5-b][1,4]diazepines 4a-f and 4-amino-8-aryl-6-(1,3-benzodioxol-5-yl)-8,9-dihydro-7H-pyrimido[4,5-b][1,4]diazepines 5a-f were obtained regioselectively from the reaction of 4,5,6-triaminopyrimidine 1 with 1equiv of methylenedioxychalcones 2a-f and 3a-f, under microwave irradiation. Detailed NMR measurements confirm the high regioselectivity of this reaction. These compounds have been evaluated in the US National Cancer Institute (NCI) for their ability to inhibit approximately 60 different human tumor cell lines, where 4e, 5a and 5b presented remarkable activity against 47, 11 and 37 cancer cell lines, respectively, with the most important GI50 values ranging from 0.068 to 0.35 microM, in vitro assay.