1,353 research outputs found

    Aberrant activation of ERK/FOXM1 signaling cascade triggers the cell migration/invasion in ovarian cancer cells

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    Forkhead box M1 (FOXM1) is a proliferation-associated transcription factor essential for cell cycle progression. Numerous studies have documented that FOXM1 has multiple functions in tumorigenesis and its elevated levels are frequently associated with cancer progression. Here, we characterized the role of ERK/FOXM1 signaling in mediating the metastatic potential of ovarian cancer cells. Immunohistochemical (IHC), immunoblotting and semi-quantitative RT-PCR analyses found that both phospho-ERK and FOXM1 were frequently upregulated in ovarian cancers. Intriguingly, the overexpressed phospho-ERK (p<0.001) and FOXM1 (p<0.001) were significantly correlated to high-grade ovarian tumors with aggressive behavior such as metastasized lymph node (5 out of 6). Moreover, the expressions of phospho-ERK and FOXM1 had significantly positive correlation (p<0.001). Functionally, ectopic expression of FOXM1B remarkably enhanced cell migration/invasion, while FOXM1C not only increased cell proliferation but also promoted cell migration/invasion. Conversely, inhibition of FOXM1 expression by either thiostrepton or U0126 could significantly impair FOXM1 mediated oncogenic capacities. However, the down-regulation of FOXM1 by either thiostrepton or U0126 required the presence of p53 in ovarian cancer cells. Collectively, our data suggest that over-expression of FOXM1 might stem from the constitutively active ERK which confers the metastatic capabilities to ovarian cancer cells. The impairment of metastatic potential of cancer cells by FOXM1 inhibitors underscores its therapeutic value in advanced ovarian tumors. Ā© 2011 Lok et al.published_or_final_versio

    Maintenance H2-antagonist is not necessary after eradication of Helicobacter pylori in bleeding peptic ulcers

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    DLX1 acts as a crucial target of FOXM1 to promote ovarian cancer aggressiveness by enhancing TGF-Ī²/SMAD4 signaling

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    Recent evidence from a comprehensive genome analysis and functional studies have revealed that FOXM1 is a crucial metastatic regulator that drives cancer progression. However, the regulatory mechanism by which FOXM1 exerts its metastatic functions in cancer cells remains obscure. Here, we report that DLX1 acts as a FOXM1 downstream target, exerting pro-metastatic function in ovarian cancers. Both FOXM1 isoforms (FOXM1B or FOXM1C) could transcriptionally upregulate DLX1 through two conserved binding sites, located at +61 to +69bp downstream (TFBS1) and -675 to -667bp upstream (TFBS2) of the DLX1 promoter, respectively. This regulation was further accentuated by the significant correlation between the nuclear expression of FOXM1 and DLX1 in high-grade serous ovarian cancers. Functionally, the ectopic expression of DLX1 promoted ovarian cancer cell growth, cell migration/invasion and intraperitoneal dissemination of ovarian cancer in mice, whereas small interfering RNA-mediated DLX1 knockdown in FOXM1-overexpressing ovarian cancer cells abrogated these oncogenic capacities. In contrast, depletion of FOXM1 by shRNAi only partially attenuated tumor growth and exerted almost no effect on cell migration/invasion and the intraperitoneal dissemination of DLX1-overexpressing ovarian cancer cells. Furthermore, the mechanistic studies showed that DLX1 positively modulates TGF- signaling by upregulating PAI-1 and JUNB through direct interaction with SMAD4 in the nucleus upon TGF-1 induction. Taken together, these data strongly suggest that DLX1 plays a pivotal role in FOXM1 signaling to promote cancer aggressiveness through intensifying TGF-/SMAD4 signaling in high-grade serous ovarian cancer cells.published_or_final_versio

    Highly pathogenic avian influenza H5N1 virus delays apoptotic responses via activation of STAT3

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    Highly pathogenic avian influenza (HPAI) H5N1 virus continues to pose pandemic threat, but there is a lack of understanding of its pathogenesis. We compared the apoptotic responses triggered by HPAI H5N1 and low pathogenic H1N1 viruses using physiologically relevant respiratory epithelial cells. We demonstrated that H5N1 viruses delayed apoptosis in primary human bronchial and alveolar epithelial cells (AECs) compared to H1N1 virus. Both caspase-8 and -9 were activated by H5N1 and H1N1 viruses in AECs, while H5N1 differentially up-regulated TRAIL. H5N1-induced apoptosis was reduced by TRAIL receptor silencing. More importantly, STAT3 knock-down increased apoptosis by H5N1 infection suggesting that H5N1 virus delays apoptosis through activation of STAT3. Taken together, we demonstrate that STAT3 is involved in H5N1-delayed apoptosis compared to H1N1. Since delay in apoptosis prolongs the duration of virus replication and production of pro-inflammatory cytokines and TRAIL from H5N1-infected cells, which contribute to orchestrate cytokine storm and tissue damage, our results suggest that STAT3 may play a previously unsuspected role in H5N1 pathogenesis.published_or_final_versio

    Lansoprazole for the prevention of recurrences of ulcer complications from long-term low-dose aspirin use

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    Background: The role of gastric acid suppression in preventing the recurrence of ulcer complications after the eradication of Helicobacter pylori infection in patients taking long-term low-dose aspirin is uncertain. Methods: We enrolled 123 patients who had ulcer complications after using low-dose aspirin continuously for more than one month and who had H. pylori infection. After the ulcers had healed and the H. pylori infection was eradicated, the patients were randomly assigned to treatment with 30 mg of lansoprazole daily or placebo, in addition to 100 mg of aspirin daily, for 12 months. The primary end point was the recurrence of ulcer complications. Results: During a median follow-up of 12 months, 9 of the 61 patients in the placebo group (14.8 percent), as compared with 1 of the 62 patients in the lansoprazole group (1.6 percent), had a recurrence of ulcer complications (adjusted hazard ratio, 9.6; 95 percent confidence interval, 1.2 to 76.1). Of these 10 patients, 4 had evidence of a recurrence of H. pylori infection and 2 had taken nonsteroidal antiinflammatory drugs before the onset of complications. Patients in the lansoprazole group were significantly less likely to have a recurrence of ulcer complications than patients in the placebo group (P=0.008). There was no significant difference in mortality between the two groups. Conclusions: In patients who had ulcer complications related to the long-term use of low-dose aspirin, treatment with lansoprazole in addition to the eradication of H. pylori infection significantly reduced the rate of recurrence of ulcer complications. Copyright Ā© 2002 Massachusetts Medical Society.published_or_final_versio

    Intrusion detection routers: Design, implementation and evaluation using an experimental testbed

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    In this paper, we present the design, the implementation details, and the evaluation results of an intrusion detection and defense system for distributed denial-of-service (DDoS) attack. The evaluation is conducted using an experimental testbed. The system, known as intrusion detection router (IDR), is deployed on network routers to perform online detection on any DDoS attack event, and then react with defense mechanisms to mitigate the attack. The testbed is built up by a cluster of sufficient number of Linux machines to mimic a portion of the Internet. Using the testbed, we conduct real experiments to evaluate the IDR system and demonstrate that IDR is effective in protecting the network from various DDoS attacks. Ā© 2006 IEEE.published_or_final_versio

    Three-day lansoprazole quadruple therapy for Helicobacter pylori-positive duodenal ulcers: a randomized contolled study

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    Assessment right atrial thrombus by real-time three dimensional transthoracic echocardiography in patient with dilated cardiomyopathy

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    We report a case of a 52-year-old patient with dilated cardiomyopathy who presented with worsening heart failure. Two-dimensional transthoracic echocardiography and real-time three dimensional transthoracic echocardiography showed severe dilated cardiac chambers, impaired ejection fraction and a mobile right atrial thrombus 2.6 Ɨ 1.0 cm in size, traversing the right atrial cavity during the whole cardiac cycle. After one week therapeutic anticoagulation, echocardiography confirmed no evidence of residual thrombus

    Elevated adipogenesis of marrow mesenchymal stem cells during early steroid-associated osteonecrosis development

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    <p>Abstract</p> <p>Background</p> <p>Increased bone marrow lipid deposition in steroid-associated osteonecrosis (ON) implies that abnormalities in fat metabolism play an important role in ON development. The increase in lipid deposition might be explained by elevated adipogenesis of marrow mesenchymal stem cells (MSCs). However, it remains unclear whether there is a close association between elevated adipogenesis and steroid-associated ON development.</p> <p>Objective</p> <p>The present study was designed to test the hypothesis that there might be a close association between elevated adipogenesis and steroid-associated ON development.</p> <p>Methods</p> <p>ON rabbit model was induced based on our established protocol. Dynamic-MRI was employed for local intra-osseous perfusion evaluation in bilateral femora. Two weeks after induction, bone marrow was harvested for evaluating the ability of adipogenic differentiation of marrow MSCs at both cellular and mRNA level involving adipogenesis-related gene peroxisome proliferator-activated receptor gamma2 (PPARĪ³2). The bilateral femora were dissected for examining marrow lipid deposition by quantifying fat cell number, fat cell size, lipid deposition area and ON lesions. For investigating association among adipogenesis, lipid deposition and perfusion function with regard to ON occurrence, the rabbits were divided into ON<sup>+ </sup>(with at least one ON lesion) group and ON<sup>- </sup>(without ON lesion) group. For investigating association among adipogenesis, lipid deposition and perfusion function with regard to ON extension, the ON<sup>+ </sup>rabbits were further divided into sub-single-lesion group (SON group: with one ON lesion) and sub-multiple-lesion group (MON group: with more than one ON lesion).</p> <p>Results</p> <p>Local intra-osseous perfusion index was found lower in either ON<sup>+ </sup>or MON group when compared to either ON<sup>- </sup>or SON group, whereas the marrow fat cells number and area were much larger in either ON<sup>+ </sup>or MON group as compared with ON<sup>- </sup>and SON group. The adipogenic differentiation ability of MSCs and PPARĪ³2 expression in either ON<sup>+ </sup>or MON group were elevated significantly as compared with either ON<sup>- </sup>or SON group.</p> <p>Conclusion</p> <p>These findings support our hypothesis that there is a close association between elevated adipogenesis and steroid-associated osteonecrosis development.</p
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