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Glioma remains one of the most aggressive and lethal cancers in central nervous system. Temozolomide (TMZ) is the most commonly used chemotherapeutic agent in gliomas. However, therapeutic benefits of TMZ could be very limited and all patients would finally suffer from tumor progression as the tumors develop resistance to TMZ. In this study, we aim to investigate the underlying mechanism of chemoresistance in glioma cell line and to identify whether there is still a close link between epithelial-mesenchymal transition (EMT) and TMZ resistance in gliomas. The real-time RT-PCR and Western blotting were used to measure the expression of EMT markers in TMZ-resistant cells. The migration and invasion assays were conducted to detect the cell motility activity in TMZ-resistant cells. The transfection was used to down-regulate the Cdc20 expression. The student t-test was applied for data analysis. We established stable TMZ-resistant glioma cells and designated as TR. Our results revealed that TR cells exhibited a significantly increased resistance to TMZ compared with their parental cells. Moreover, TMZ-resistant cells had acquired EMT-like changes. For the mechanism study, we measured a significant increased expression of CDC20 and decreased expression of Bim in TR cells. Moreover, upon suppression of CDC20 by shRNA transfection, TR cells underwent a reverse of EMT features. Importantly, knockdown of CDC20 enhanced the drug sensitivity of TR cells to TMZ. Our results suggested that inactivation of CDC20 could contribute to the future therapy that possibly overcomes drug resistance in human cancers.

The molecular mechanisms of acute lung injury (ALI) are closely associated with nucleotide-binding domains and leucine-rich repeat (NLR) pyrin domains containing 3 (NLRP3) inflammasome, in which alveolar macrophages (AMs) exert an essential function. Our study has been proved that artesunate (AS) inhibits ALI. Nevertheless, the inhibition actions of AS on activation of NLRP3 in renal ischemia-reperfusion (RIR)-mediated ALI remain to be further discussed. Male Sprague-Dawley rats were randomly assigned into four groups: sham + NS, sham + AS, RIR + NS, and RIR + AS. RIR-mediated ALI was performed through bilateral renal pedicle occlusion for 60 min followed by reperfusion for 24 h. AS (15 mg/kg) or NS was injected intraperitoneal to rat 1 h before RIR treatment. AMs were rendered hypoxic (0.5%) for 2 h and reoxygenated for 24 h. Lung injury index and histology, and inflammatory cells and cytokine release in the BALF and AMs were examined. The protein and mRNA levels of NLRP3, ASC, and caspase-1 in the lung and AMs were evaluated via Western blot and real-time RCR. In this research, we indicated that AS preconditioning inhibited RIR-mediated lung damage, vascular permeability, and edema in rats. AS reduced RIR-mediated ALI, as characterized by abatement in the count of inflammatory cells, and the production of inflammatory cytokines in the BALF. AS administration inhibited the number of F4/80-positive cells, the activity of myeloperoxidase, and the fiery cytokines mRNA expression in lung samples of RIR-stimulated rats. Furthermore, AS alleviated the activity of caspase-1 and activation of NLRP3 through depending on reactive oxygen species (ROS). An in vitro finding that AS mitigated hypoxia/reoxygenation-mediated activation of AMs partially supported in vivo study. In a word, these findings demonstrate that AS pretreatment attenuated RIR-mediated ALI potentially through reducing ROS-induced activation of the NLRP3 inflammasome.

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