Cigarette Smoke Induces Gefitinib Resistance in NSCLC Cells via ROS/Sirt3/SOD2 Pathway / 中国肺癌杂志

BACKGROUND@#Epidermal growth factor receptor (EGFR) gene mutations are the most common driver mutations in non-small cell lung cancer (NSCLC). To prolong the survival of the patients, EGFR tyrosine kinase inhibitors (TKIs) resistance in NSCLC is a major challenge that needs to be addressed urgently, and this study focuses on investigating the mechanism of cigarette smoke (CS) induced Gefitinib resistance in NSCLC.@*METHODS@#PC-9 and A549 cells were cultured in vitro and treated with 1 µmol/L Gefitinib for 4 h and 10% cigarette smoke extract (CSE) for 48 h. Western blot was used to detect Sirtuin 3 (Sirt3) and superoxide dismutase 2 (SOD2) protein expressions; DCFH-DA probe was used to detect intracellular reactive oxygen species (ROS); CCK-8 kit was used to detect cell activity, and EdU was used to detect cell proliferation ability. Sirt3 overexpression plasmid (OV-Sirt3) was transfected in PC-9 and A549 cells and treated with 1 µmol/L Gefitinib for 4 h and 10% CSE for 48 h after N-acetylcysteine (NAC) action. The expressions of Sirt3 and SOD2 were detected by Western blot; the ROS level in the cells was detected by DCFH-DA probe, and the cell activity was detected by CCK-8.@*RESULTS@#CSE induced an increase in the 50% inhibitory concentration (IC50) of both PC-9 and A549 cells to Gefitinib (P<0.01) and enhanced the proliferation of PC-9 and A549 cells, suggesting that CS induced Gefitinib resistance in NSCLC. ROS was involved in CSE-induced Gefitinib resistance (P<0.05). CSE induced low expressions of Sirt3 and SOD2 (P<0.01), and Sirt3/SOD2 was associated with poor prognosis in lung cancer patients (P<0.05). OV-Sirt3 in PC-9 and A549 cells reversed CSE-induced Gefitinib resistance (P<0.05) and significantly reduced ROS production. NAC reversed CSE-induced Gefitinib resistance in PC-9 and A549 cells (P<0.05).@*CONCLUSIONS@#The ROS/Sirt3/SOD2 pathway is involved in CS-induced Gefitinib resistance in NSCLC.

Synergistic effect of β-thujaplicin and tigecycline against tet(X4)-positive Escherichia coli in vitro / 生物工程学报

The widespread of tigecycline resistance gene tet(X4) has a serious impact on the clinical efficacy of tigecycline. The development of effective antibiotic adjuvants to combat the looming tigecycline resistance is needed. The synergistic activity between the natural compound β-thujaplicin and tigecycline in vitro was determined by the checkerboard broth microdilution assay and time-dependent killing curve. The mechanism underlining the synergistic effect between β-thujaplicin and tigecycline against tet(X4)-positive Escherichia coli was investigated by determining cell membrane permeability, bacterial intracellular reactive oxygen species (ROS) content, iron content, and tigecycline content. β-thujaplicin exhibited potentiation effect on tigecycline against tet(X4)-positive E. coli in vitro, and presented no significant hemolysis and cytotoxicity within the range of antibacterial concentrations. Mechanistic studies demonstrated that β-thujaplicin significantly increased the permeability of bacterial cell membranes, chelated bacterial intracellular iron, disrupted the iron homeostasis and significantly increased intracellular ROS level. The synergistic effect of β-thujaplicin and tigecycline was identified to be related to interfere with bacterial iron metabolism and facilitate bacterial cell membrane permeability. Our studies provided theoretical and practical data for the application of combined β-thujaplicin with tigecycline in the treatment of tet(X4)-positive E. coli infection.

El estrés oxidativo en la enfermedad cardiovascular: evidencias para un tratamiento más integral / Oxidative stress in cardiovascular disease: evidences for a more integral treatment

La revolución que se produjo en las áreas de la salud en el mundo durante el siglo XX, o lo que se ha dado en llamar la transición epidemiológica, ha hecho que la población mundial envejezca y con ello las enfermedades crónicas no trasmisibles, aparezcan cada vez con mayor frecuencia. Entre estas, las enfermedades cardiovasculares, específicamente las del corazón, son las de mayor incidencia. El oxígeno es esencial para la vida, pero posee una paradoja en los organismos que lo utilizan. Este elemento desempeña una función importante como aceptor final de electrones durante la respiración celular, pero también constituye el punto de partida para un tipo de daño celular conocido como estrés oxidativo. La experiencia clínica y los estudios prospectivos constituyen una herramienta de gran utilidad, lo cual ha permitido establecer una asociación entre el estrés oxidativo y las enfermedades cardiovasculares, se plantea que este es un evento precoz en el desarrollo de la disfunción endotelial y de la subsecuente afección cardiovascular. En el presente trabajo se realizó una revisión bibliográfica actualizada sobre la función del estrés oxidativo y las especies reactivas de oxígeno en la fisiopatología de estas enfermedades.

Changes occurred in health areas at world level during XX Century, or the so called epidemiologic transition, lead to world population aging, and thus the non-communicable chronic diseases, appear with more and more frequency. Among them, cardiovascular diseases, specifically those of heart, have the greater incidence. Oxygen is essential for life, but it has a paradox in organisms used it. This element has a significant role as final acceptor of electrons during cellular breathing, but also is start point of cellular damage known as oxidative stress. Clinical experience and prospective studies is a very useful tool, which has allowed us to establish an association between oxidative stress and cardiovascular diseases. We propose that this is an early event in development of endothelial dysfunction and the subsequent cardiovascular affection. In present paper we made a updated bibliographic review on role of oxidative stress, and the reactive species of oxygen in physiopathology of these diseases.