We found that beta-lapachone (beta-lap), a novel bioreductive drug, caused rapid apoptosis and clonogenic cell death in A549 human lung epithelial cancer cells in vitro in a dose-dependent manner. The clonogenic cell death caused by beta-lap could be significantly inhibited by dicoumarol, an inhibitor of NAD(P)H:quinone oxido-reductase (NQO1), and also by siRNA for NQO1, demonstrating that NQO1-induced bioreduction of beta-lap is an essential step in beta-lap-induced cell death. Irradiation of A549 cells with 4 Gy caused a long-lasting upregulation of NQO1, thereby increasing NQO1-mediated beta-lap-induced cell deaths. Although the direct cause of beta-lap-induced apoptosis is not yet clear, beta-lap treatment reduced the expression of p53 and NF-kappaB, whereas it increased cytochrome C release, caspase-3 activity, and gammaH2AX foci formation. Importantly, beta-lap treatment immediately after irradiation enhanced radiation-induced cell death, indicating that beta-lap sensitizes cancer cells to radiation, in addition to directly killing some of the cells. The growth of A549 tumors induced in immunocompromised mice could be markedly suppressed by local radiation therapy when followed by beta-lap treatment. This is the first study to demonstrate that combined radiotherapy and beta-lap treatment can have a significant effect on human tumor xenografts.
Using detailed administrative records, we find that, on average, women receive lighter sentences in comparison with men along both extensive and intensive margins. Using parametric and semiparametric decomposition methods, roughly 30% of the gender differences in incarceration cannot be explained by the observed criminal characteristics of offense and offender. We also find evidence of considerable heterogeneity across judges in their treatment of female and male offenders. There is little evidence, however, that tastes for gender discrimination are driving the mean gender disparity or the variance in treatment between judges.
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