30 research outputs found

    Multinationals FDI and uncertainty: A comment

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    This paper re-examines the model developed by Firoozi [Firoozi, F., 1997. Multinational FDI and uncertainty: an exposition. Journal of Multinational Financial Management 7, 265-273] to study foreign direct investment (FDI) by multinationals facing cost uncertainty. Firoozi shows that a mean-preserving-spread increase in cost uncertainty has an ambiguous effect on the optimal level of FDI. Contrary to his findings, we show that the FDI-uncertainty connection is de facto negative, confined to his model and under reasonable assumptions on multinationals' preferences.link_to_subscribed_fulltex

    An angiogenic function for E-cadherin in ovarian cancer

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    Meeting Theme: Harnessing Breakthroughs - Targeting CuresSession - Tumor Biology: Poster Presentations - Angiogenesis 1: Molecular and Cellular Mechanisms: abstract no. 9This journal suppl. entitled: Proceedings: AACR Annual Meeting 2014The loss of E-cadherin, a cell-cell adhesion molecule, is a well-established marker for metastasis of cancer. Although E-cadherin is synthesized as a transmembrane molecule, it can be cleaved of the ectodomain and released in a soluble form (sE-cad), and this accounts a key mechanism for a rapid reduction of functional E-cadherin at the cell surface. Yet, very little is known about how this important protein dictates the metastasis of these tumors. In ovarian cancer, a highly metastatic tumor that is rapidly lethal, sE-cad is highly expressed in the serum and metastatic ascites of ovarian carcinoma patients. Despite many studies focused on the role of E-cadherin loss in weakening cell-cell adhesion, whether sE-cad has biological activity in itself remain virtually unknown. Here we show for the first time that sE-cad can transduce angiogenic signals. sE-cad was also present in the culture supernatant of ovarian cancer lines. sE-cad of supernatant and a recombinant sE-cad-Fc chimera potently stimulated the migration of, permeability, and tubulogenesis by human umbilical vein endothelial cells in vitro. sE-cad also promoted functional neovascularization in a Matrigel implant model in vivo. These effects could be reversed by neutralizing anti-sE-cad, confirming that the effects were sE-cad specific. In addition, we found that sE-cad bound to VE-cadherin, an effect mediated through the phosphatidylinositol 3-kinase/Akt-β-catenin pathway. These results unravel a new and important piece to the complex biology of tumor angiogenesis and metastasis, and provide insights of novel mechanisms regulating angiogenesis. (This study was supported by RGC grant HKU781013). ©2014 American Association for Cancer Research

    Loss of BRCA1 regulates autophagy as a cellular stress response in breast and ovarian cancer cells

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    Poster Session 1 - Autophagy and Altered Mitochondrial Function: abstract no. 3790Inactivation of cell death is a major step in tumor development. The BRCA1 tumor suppressor, which is frequently mutated in human breast and ovarian cancers, is a critical mediator of cell death. Although the role of BRCA1 gene loss for inhibiting apoptosis is well established, little is known regarding its ...link_to_OA_fulltextThe 102nd Annual Meeting of American Association for Cancer Research (AACR), Orlando, FL., 2-6 April 2011

    Mergers and investments in cost reduction with private information revisited

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    This paper re-examines the model developed by Stenbacka (1991) which addresses the investment incentives of an innovating firm operating in anticipation of a merger with its rival in a Cournot duopoly setting. In contrast to Stenbacka, we find that the innovating firm need not always invest more should it conceal rather than reveal its R&D outcome prior to the takeover. Furthermore, we show that the ex ante incentive for the innovating firm to conceal its private information is perfectly consistent with earlier findings in the information sharing literature. (C) 1997 Published by Elsevier Science B.V

    c-Met overexpression contributes to the acquired apoptotic resistance of nonadherent ovarian cancer cells through a cross talk mediated by phosphatidylinositol 3-kinase and extracellular signal-regulated kinase 1/2

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    Ovarian cancer is the most lethal gynecologic cancer mainly because of widespread peritoneal dissemination and malignant ascites. Key to this is the capacity of tumor cells to escape suspension-induced apoptosis (anoikis), which also underlies their resistance to chemotherapy. Here, we used a nonadherent cell culture model to investigate the molecular mechanisms of apoptotic resistance of ovarian cancer cells that may mimic the chemoresistance found in solid tumors. We found that ovarian cancer cells acquired a remarkable resistance to anoikis and apoptosis induced by exposure to clinically relevant doses of two front-line chemotherapeutic drugs cisplatin and paclitaxel when grown in three-dimensional than monolayer cultures. Inhibition of the hepatocyte growth factor (HGF) receptor c-Met, which is frequently overexpressed in ovarian cancer, by a specific inhibitor or small interfering RNA blocked the acquired anoikis resistance and restored chemosensitivity in three-dimensional not in two-dimensional cultures. These effects were found to be dependent on both phosphatidylinositol 3-kinase (PI3K)/Akt and extracellular signal-regulated kinase (ERK) 1/2 signaling pathways. Inhibitors of PI3K/Akt abrogated ERK1/2 activation and its associated anoikis resistance in response to HGF, suggesting a signaling relay between these two pathways. Furthermore, we identified a central role of Ras as a mechanism of this cross talk. Interestingly, Ras did not lie upstream of PI3K/Akt, whereas PI3K/Akt signaling to ERK1/2 involved Ras. These findings shed new light on the apoptotic resistance mechanism of nonadherent ovarian cancer ascites cells and may have important clinical implications. Copyright © 2010 Neoplasia Press, Inc. All rights reserved.link_to_OA_fulltex

    c-Met overexpression contributes to the acquired apoptosis resistance of non-adherent ovarian cancer cells through a cross-talk mediated by phosphatidylinositol 3-kinase and extracellular signal-regulated kinase 1/2

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    Poster Session 29 - Receptor Signaling in Endocrine Related Cancers: abstract no. 1722Ovarian cancer is the most lethal gynecological cancer mainly due to widespread peritoneal dissemination and malignant ascites. Key to this is the capacity of tumor cells to escape suspension-induced apoptosis (anoikis), which also underlies their resistance to chemotherapy. Here we utilized a non-adherent cell culture model to investigate molecular mechanisms of apoptotic resistance of ovarian cancer cells that may mimic the chemoresistance found in solid tumors. We found that ovarian cancer cells acquired a remarkable resistance to anoikis and apoptosis induced by exposure to clinically relevant doses of two front-line chemotherapeutic drugs cisplatin and paclitaxel when grown in three-dimensional (3D) than monolayer cultures. Inhibition of the hepatocyte growth factor (HGF) receptor c-Met, which is frequently overexpressed in ovarian cancer, by a specific inhibitor or small interfering RNA blocked the acquired anoikis resistance and restored chemosensitivity in 3D, not in 2D cultures. These effects were found to be dependent on both phosphatidylinositol 3-kinase (PI3K)/Akt and extracellular-signal regulated kinase (ERK) 1/2 signaling pathways. Inhibitors of PI3K/Akt abrogated ERK1/2 activation and its associated anoikis resistance in response to HGF, suggesting a signaling relay between these two pathways. Furthermore, we identified, as a mechanism of this cross-talk, a central role of Ras. Interestingly, Ras did not lie upstream of PI3K/Akt, whereas PI3K/Akt signaling to ERK1/2 involved Ras. These findings shed new light on the apoptotic resistance mechanism of non-adherent ovarian cancer ascites cells.link_to_OA_fulltextThe 101st Annual Meeting of the American Association for Cancer Research (AACR 2010), Washington D.C., 17-21 April 2010. In AACR Meeting Abstracts, 201

    A Cross-Sectional Study of the Clinical Metrics of Functional Status Tools in Pediatric Critical Illness.

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    OBJECTIVES: To determine the clinical metrics of functional assessments in pediatric critical illness survivors. DESIGN: Cross-sectional observational study. SETTING: PICU follow-up clinic. PATIENTS: Forty-four PICU survivors 6-12 months post PICU stay, and 52 healthy controls 0-18 years old. INTERVENTIONS: Nil. MEASUREMENTS AND MAIN RESULTS: Function was assessed using the Pediatric Quality of Life Inventory 4.0 generic scales and infant scales, the Pediatric Evaluation of Disability Inventory-Computer Adaptive Test, and the Functional Status Scale. Muscle strength was assessed by hand grip strength in children greater than or equal to 6 years. Clinical metrics assessed included floor and ceiling effects, known-group, and convergent validity. Floor and ceiling effects were present if the participants achieving the worst or best scores exceeded 15%, respectively. Known-group validity was assessed by comparing scores between those with and without complex chronic conditions and abnormal versus good baseline function. Convergent validity was assessed using partial correlation between two tools. Functional Status Scale and Pediatric Quality of Life Inventory physical domain scores showed significant ceiling effects in PICU survivors (69.2% and 15.4%, respectively, achieved the highest possible score). Functional scores were not significantly different between children with or without complex chronic conditions or children with good versus abnormal baseline function. In healthy children, Pediatric Quality of Life Inventory physical correlated moderately with hand grip strength (partial r = 0.66; p < 0.001), whereas Pediatric Quality of Life Inventory psychosocial correlated moderately with Pediatric Evaluation of Disability Inventory-Computer Adaptive Test social/cognitive score (partial r = 0.53; p < 0.001). In PICU survivors, only Pediatric Quality of Life Inventory physical and Pediatric Evaluation of Disability Inventory-Computer Adaptive Test mobility scores were correlated (partial r = 0.55; p < 0.001). CONCLUSIONS: PICU functional assessment tools have varying clinical metrics. Considering ceiling effects, Pediatric Evaluation of Disability Inventory-Computer Adaptive Test may be more suitable in survivors than Functional Status Scale. Differences in scores between children with or without complex chronic conditions, and with or without baseline functional impairment, were not observed. Functional assessments likely require a combination of tools to measure the spectrum of pediatric critical illness and recovery
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