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Objective: To investigate the role of microRNA-31 (miR-31) in osteosarcoma and the molecular mechanism of miR-31 in proliferation and apoptosis of osteosarcoma. Methods: real-time quantitative PCR (qRT-PCR) was used to detect the expression of miR-31 in human osteosarcoma. Pearson 's chisquared was applied to detect the correlation between miR-31 and clinicopathological features. CCK-8 and ANNEXIN-FITC/PI double staining were used to detect the proliferation and apoptosis of osteosarcoma cells. Results: The results of qRT-PCR showed that the expression of miR-31 was down-regulated in osteosarcoma tissues compared with matched precancerous bone tissues. The level of miR-31 in osteosarcoma tissues with high-grade malignancy and poor overall survival was even lower. CCK-8 and Annexin-FITC/PI double staining assays showed that miR-31 inhibited proliferation and promoted apoptosis of osteosarcoma cells. According to luciferase assay, miR-31 inhibited PAX9 expression directly. And PAX9 promoted proliferation and inhibited apoptosis of osteosarcoma cells. Conclusion: miR-31 inhibits proliferation and promotes apoptosis of osteosarcoma cells by targeting PAX9. miR-31 and PAX9 can be used as therapeutic targets for osteosarcoma. [ABSTRACT FROM AUTHOR]

Objective: To study the significance of mir-141 expression in COPD (chronic obstructive pulmonary diseases) mononuclear cells, and to demonstrate its effect on proliferation and apoptosis of fibroblasts Possible to ZEB1(zinc finger E-box binding homeobox 1). Methods: 40 cases acute phase of COPD patients, 80 cases of stable period COPD patients and 110 normal controls in our hospital were collected. RT-PCR was used to detect mir-141 and statistical analysis. The mir-141 mimic was constructed and transfected into lung fibroblasts. The expression of mir-141 was analyzed by RT-PCR. Cell proliferation was analyzed by CCK8 and cell apoptosis was detected by flow cytometry. Targetscan was used to predict the binding site of ZEB1 and mir-141. The target relationship between ZEB1 and mir-141 was identified by RT-PCR and western blot. Results: The expression of mir-141 in mononuclear cells of acute phase of COPD and stable period of COPD was significantly higher than that of normal controls. Mir-141 levels in acute phase of COPD were significantly higher than that of stable period of COPD. Mir-141 mimic transfection significantly up-regulated the expression of mir- 141, promoted cell activity and decreased cell apoptosis rate compared with the empty control group. ZEB1 and mir-141 had binding sites predicted by Targetscan database and verified by dual luciferase assays. After mir-141 mimic transfection hat, ZEB1 mRNA and protein expression were down-regulated. Conclusions: High expression of mir-141 in COPD may promote the proliferation of lung fibroblasts and inhibit apoptosis by targeting ZEB1. [ABSTRACT FROM AUTHOR]

Cordycepin is an active component of the traditional Chinese medicine Cordyceps sinensis and Cordyceps militaris with notable anticancer activity. Though the prominent inhibitory activity was reported in different kinds of cancer cell lines, the concrete mechanisms remain elusive. It was reported that cordycepin could be converted into tri-phosphates in vivo to confuse a number of enzymes and interfere the normal cell function. For the inhibitory mechanism of EGFR inhibitors and the structure similarity of ATP and tri-phosphated cordycepin, human lung cancer cell line H1975 was employed to investigate the inhibitory effect of cordycepin. The results showed that cordycepin could inhibit cell proliferation and induce apoptosis in a dose-dependent manner. Cell cycle analysis revealed that H1975 cells could be arrested at the G0/G1 phase after cordycepin treatment. The expression levels of apoptosis-related protein Caspase-3 and Bcl-2 and phosphorylated expression levels of EGFR, AKT and ERK1/2 were all decreased compared with the control group stimulated with EGF. However, the protein expression levels of proapoptotic protein Bax and cleaved caspase-3 were increased. These results implied that cordycepin could inhibit cell proliferation and induce apoptosis via the EGFR signaling pathway. Our results indicated that there was potential to seek a novel EGFR inhibitor from cordycepin and its chemical derivatives. [ABSTRACT FROM AUTHOR]

The modification of Wnt and Notch signaling pathways by hypoxia, and its association with osteoblast proliferation and apoptosis remain to be fully elucidated. To investigate Wnt-Notch crosstalk, and its role in hypoxia-induced osteoblast proliferation and apoptosis regulation, the present study investigated the effects of cobalt-mimicked hypoxia on the mouse pre-osteoblast-like cell line, MC3T3-E1, when the Notch signals were repressed using a γ-secretase inhibitor DAPT. The data showed that the cobalt-mimicked hypoxia suppressed cell proliferation under normal conditions, but increased cell proliferation under conditions of Notch repression, in a concentration-dependent manner. The results of western blot and reverse transcription-quantitative polymerase chain reaction analyses showed that the cobalt treatment increased the levels of activated β-catenin protein and the expression levels of the target genes, axis inhibition protein 2 and myelocytomatosis oncogene, under DAPT-induced Notch repression. However, no significant changes were found in the expression levels of the Notch intracellular domain protein or the Notch target gene, hes1. In a β-catenin gene-knockdown experiment, the proliferation of the MC3T3-E1 cells under hypoxia were decreased by DAPT treatment, and knockdown of the expression of hypoxia-inducible factor-1α (HIF-1α) suppressed the cobalt-induced increase in Wnt target gene levels. No significant difference in cell proliferation rate was found following DAPT treatment when the expression of HIF-1α was knocked down. The results of the present study showed the opposing effects of Wnt and Notch signaling under cobalt-mimicked hypoxia, which were partially regulated by HIF-1α, The results also showed that osteoblast proliferation was dependent on Wnt-Notch signal crosstalk. [ABSTRACT FROM AUTHOR]