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.

Ginsenoside Rb1 Attenuates Human Umbilical Vein Endothelial Cells Senescence Induced by High Glucose through Sirt3/SOD2 Pathway / 中山大学学报(医学科学版)

@#Abstract】 【Objective】To investigate the effect and mechanism of ginsenoside Rb1 attenuating human umbilical vein endothelial cells(HUVEC) senescence induced by high glucose through Sirt3/SOD2 pathway.【Methods】The senescence of HUVEC induced by high glucose(40 mmol/L)was assessed by senescence-associated β-galactosidase(SA-β-Gal)staining,and the expression of plasminogen activator inhibitor 1(PAI-1)and P16. Annexin V-FITC/PI was performed to measure apoptotic effect. The expression of sirtuins 3(Sirt3)and superoxide dismutase 2(SOD2)was detected by western blot. Meanwhile,the level of intracellular malondialdehyde(MDA)and the activity of SOD2 were measured.【Results】Treatment of HUVEC with high glucose for 24 hours induced premature senescence instead of apoptosis,as indicated by a larger proportion of the cells stained with SA-β-Gal and the up-regulated expression of PAI-1 and P16. Pretreatment of HUVEC with ginsenoside Rb1(40 μmol/L)could reverse endothelial cell senescence,as indicated by the reduced SA-β-Gal positive cells and the down-regulated expression of PAI-1 and P16. Furthermore,ginsenoside Rb1 pretreatment upregulated the protein expression of Sirt3 and SOD2,and eventually increased the activity of SOD2 and decreased the level of MDA.【Conclusion】Ginsenoside Rb1 could antagonize high glucose-induced premature senescence of HUVEC via Sirt3/SOD2 signaling pathway.

Moderate-intensity exercise allows enhanced protection against oxidative stress-induced cardiac dysfunction in spontaneously hypertensive rats

The progression of myocardial injury secondary to hypertension is a complex process related to a series of physiological and molecular factors including oxidative stress. This study aimed to investigate whether moderate-intensity exercise (MIE) could improve cardiac function and oxidative stress in spontaneously hypertensive rats (SHRs). Eight-week-old male SHRs and age-matched male Wistar-Kyoto rats were randomly assigned to exercise training (treadmill running at a speed of 20 m/min for 1 h continuously) or kept sedentary for 16 weeks. Cardiac function was monitored by polygraph; cardiac mitochondrial structure was observed by scanning electron microscope; tissue free radical production was measured using dihydroethidium staining. Expression levels of SIRT3 and SOD2 protein were measured by western blot, and cardiac antioxidants were assessed by assay kits. MIE improved the cardiac function of SHRs by decreasing left ventricular systolic pressure (LVSP), and first derivation of LVP (+LVdP/dtmax and −LVdP/dtmax). In addition, exercise-induced beneficial effects in SHRs were mediated by decreasing damage to myocardial mitochondrial morphology, decreasing production of reactive oxygen species, increasing glutathione level, decreasing oxidized glutathione level, increasing expression of SIRT3/SOD2, and increasing activity of superoxide dismutase. Exercise training in SHRs improved cardiac function by inhibiting hypertension-induced myocardial mitochondrial damage and attenuating oxidative stresses, offering new insights into prevention and treatment of hypertension.