Examinando por Autor "Montorfano, Ignacio"

Mostrando 1 - 4 de 4
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    Chalcone-induced apoptosis through caspase-dependent intrinsic pathways in human hepatocellular carcinoma cells
    (MDPI AG, 2016-02) Ramirez-Tagle, Rodrigo; Escobar, Carlos A.; Romero, Valentina; Montorfano, Ignacio; Armisén, Ricardo; Borgna, Vincenzo; Jeldes, Emanuel; Pizarro, Luis; Simon, Felipe; Echeverria, Cesar
    Hepatocellular carcinoma (HCC) is one of the most commonly diagnosed cancers worldwide. Chemoprevention of HCC can be achieved through the use of natural or synthetic compounds that reverse, suppress or prevent the development of cancer progression. In this study, we investigated the antiproliferative effects and the mechanism of action of two compounds, 2,3,41 -trimethoxy-21 -hydroxy-chalcone (CH1) and 31 -bromo-3,4-dimethoxy-chalcone (CH2), over human hepatoma cells (HepG2 and Huh-7) and cultured mouse hepatocytes (HepM). Cytotoxic effects were observed over the HepG2 and Huh-7, and no effects were observed over the HepM. For HepG2 cells, treated separately with each chalcone, typical apoptotic laddering and nuclear condensation were observed. Additionally, the caspases and Bcl-2 family proteins activation by using Western blotting and immunocytochemistry were studied. Caspase-8 was not activated, but caspase-3 and -9 were both activated by chalcones in HepG2 cells. Chalcones also induced reactive oxygen species (ROS) accumulation after 4, 8 and 24 h of treatment in HepG2 cells. These results suggest that apoptosis in HepG2 was induced through: (i) a caspase-dependent intrinsic pathway; and (ii) by alterations in the cellular levels of Bcl-2 family proteins, and also, that the chalcone moiety could be a potent candidate as novel anticancer agents acting on human hepatomas.
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    Correction for Echeverría et al., "Endotoxin-Induced Endothelial Fibrosis Is Dependent on Expression of Transforming Growth Factors β1 and β2" [Infect Immun., Volume 82, no. 9, p. 3678-3686, 2014]
    (American Society for Microbiology, 2015) Echeverría, César; Montorfano, Ignacio; Tapia, Pablo; Riedel, Claudia; Cabello-Verrugio, Claudio; Simon, Felipe a
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    Endotoxin induces fibrosis in vascular endothelial cells through a mechanism dependent on transient receptor protein melastatin 7 activity
    (Public Library of Science, 2014-04) Echeverría, Cesar; Montorfano, Ignacio; Hermosilla, Tamara; Armisén, Ricardo; Velásquez, Luis A.; Cabello-Verrugio, Claudio; Varela, Diego; Simon, Felipe
    The pathogenesis of systemic inflammatory diseases, including endotoxemia-derived sepsis syndrome, is characterized by endothelial dysfunction. It has been demonstrated that the endotoxin lipopolysaccharide (LPS) induces the conversion of endothelial cells (ECs) into activated fibroblasts through endothelial-to-mesenchymal transition mechanism. Fibrogenesis is highly dependent on intracellular Ca2+ concentration increases through the participation of calcium channels. However, the specific molecular identity of the calcium channel that mediates the Ca2+ influx during endotoxin-induced endothelial fibrosis is still unknown. Transient receptor potential melastatin 7 (TRPM7) is a calcium channel that is expressed in many cell types, including ECs. TRPM7 is involved in a number of crucial processes such as the conversion of fibroblasts into activated fibroblasts, or myofibroblasts, being responsible for the development of several characteristics of them. However, the role of the TRPM7 ion channel in endotoxin-induced endothelial fibrosis is unknown. Thus, our aim was to study whether the TRPM7 calcium channel participates in endotoxin-induced endothelial fibrosis. Using primary cultures of ECs, we demonstrated that TRPM7 is a crucial protein involved in endotoxin-induced endothelial fibrosis. Suppression of TRPM7 expression protected ECs from the fibrogenic process stimulated by endotoxin. Downregulation of TRPM7 prevented the endotoxin-induced endothelial markers decrease and fibrotic genes increase in ECs. In addition, TRPM7 downregulation abolished the endotoxin-induced increase in ECM proteins in ECs. Furthermore, we showed that intracellular Ca2+ levels were greatly increased upon LPS challenge in a mechanism dependent on TRPM7 expression. These results demonstrate that TRPM7 is a key protein involved in the mechanism underlying endotoxin-induced endothelial fibrosis.
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    Endotoxin-induced endothelial fibrosis is dependent on expression of transforming growth factors β1 and β2
    (American Society for Microbiology, 2014) Echeverría, César; Montorfano, Ignacio; Tapia, Pablo; Riedel, Claudia; Cabello-Verrugio, Claudio; Simon, Felipe
    During endotoxemia-induced inflammatory disease, bacterial endotoxins circulate in the bloodstream and interact with endo thelial cells (ECs), inducing dysfunction of the ECs. We previously reported that endotoxins induce the conversion of ECs into activated fibroblasts. Through endotoxin-induced endothelial fibrosis, ECs change their morphology and their protein expres sion pattern, thereby suppressing endothelial markers and upregulating fibrotic proteins. The most commonly used fibrotic in ducers are transforming growth factor 1 (TGF- 1) and TGF- 2. However, whether TGF- 1 and TGF- 2 participate in endo toxin-induced endothelial fibrosis remains unknown. We have shown that the endotoxin-induced endothelial fibrosis process is dependent on the TGF- receptor, ALK5, and the activation of Smad3, a protein that is activated by ALK5 activation, thus sug gesting that endotoxin elicits TGF- production to mediate endotoxin-induced endothelial fibrosis. Therefore, we investigated the dependence of endotoxin-induced endothelial fibrosis on the expression of TGF- 1 and TGF- 2. Endotoxin-treated ECs induced the expression and secretion of TGF- 1 and TGF- 2. TGF- 1 and TGF- 2 downregulation inhibited the endotoxin induced changes in the endothelial marker VE-cadherin and in the fibrotic proteins -SMA and fibronectin. Thus, endotoxin in duces the production of TGF- 1 and TGF- 2 as a mechanism to promote endotoxin-induced endothelial fibrosis. To the best of our knowledge, this is the first report showing that endotoxin induces endothelial fibrosis via TGF- secretion, which represents an emerging source of vascular dysfunction. These findings contribute to understanding the molecular mechanism of endotox in-induced endothelial fibrosis, which could be useful in the treatment of inflammatory diseases