Anthraquinones have been shown to induce apoptosis in different types of tumor cells, but the mechanisms of danthron-induced cytotoxicity and apoptosis in human gastric cancer cells have not been adequately explored. This study investigated the roles of caspase cascades, ROS, DNA damage, mitochondrial disruption, and Bax and Bcl-2 proteins in danthron-induced apoptosis of SNU-1 human gastric cancer cells, a commonly used cell culture system for in vitro studies. Cells were incubated with different concentrations of danthron in a time- and/or dose-dependent manner. Cell morphological changes (shrinkage and rounding) were examined by a phase-contrast microscope, whereas cell viability and apoptotic populations were determined by flow cytometric analysis using propidium iodide (PI) and annexin V-FITC staining. The fluorescent DAPI nucleic acid stain and Comet assay were applied to detect danthron-induced chromatin condensation (an apoptotic characteristic) and DNA damage. Increasing the levels of caspase-3, -8, and -9 activities was involved in danthron-induced apoptosis, and they could be attenuated by inhibitors of specific caspases, indicating that danthron triggered the caspase-dependent apoptotic pathway. Further studies with flow cytometric analyses indicated that cellular levels of ROS, cytosolic Ca(2+), and mitochondrial permeability transition (MPT) pore opening were increased, but the level of mitochondrial membrane potential (ΔΨ(m)) was decreased. Also, the ratio of Bax/Bcl-2 levels and other proapoptotic proteins associated with modulating the ΔΨ(m) were up-regulated. Apoptotic signaling was also stimulated after exposure to danthron and determined by Western blotting and real-time PCR analyses. In summary, it is suggested that danthron-induced apoptotic cell death was involved in mitochondrial depolarization, which led to release of cytochrome c, apoptosis-inducing factor (AIF), and endonuclease G (Endo G) and caused the activation of caspase-9 and -3 in SNU-1 human gastric cancer cells.

BackgroundThe relationship between ambient air pollution exposure and mortality of cardiovascular and cerebrovascular diseases in human is controversial, and there is little information about how exposures to ambient air pollution contribution to the mortality of cardiovascular and cerebrovascular diseases among Chinese. The aim of the present study was to examine whether exposure to ambient-air pollution increases the risk for cardiovascular and cerebrovascular disease.Methodology/Principal FindingsWe conducted a retrospective cohort study among humans to examine the association between compound-air pollutants [particulate matter <10 µm in aerodynamic diameter (PM10), sulfur dioxide (SO2) and nitrogen dioxide (NO2)] and mortality in Shenyang, China, using 12 years of data (1998–2009). Also, stratified analysis by sex, age, education, and income was conducted for cardiovascular and cerebrovascular mortality. The results showed that an increase of 10 µg/m3 in a year average concentration of PM10 corresponds to 55% increase in the risk of a death cardiovascular disease (hazard ratio [HR], 1.55; 95% confidence interval [CI], 1.51 to 1.60) and 49% increase in cerebrovascular disease (HR, 1.49; 95% CI, 1.45 to 1.53), respectively. The corresponding figures of adjusted HR (95%CI) for a 10 µg/m3 increase in NO2 was 2.46 (2.31 to 2.63) for cardiovascular mortality and 2.44 (2.27 to 2.62) for cerebrovascular mortality, respectively. The effects of air pollution were more evident in female that in male, and nonsmokers and residents with BMI<18.5 were more vulnerable to outdoor air pollution.Conclusion/SignificanceLong-term exposure to ambient air pollution is associated with the death of cardiovascular and cerebrovascular diseases among Chinese populations.

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