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Title:
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FLIP is frequently expressed in endometrial carcinoma and has a role in resistance to TRAIL-induced apoptosis
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Author:
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Dolcet Roca, Xavier; Llobet Navàs, David; Pallares, Judit; Rué i Monné, Montserrat; Comella i Carnicé, Joan Xavier; Matias-Guiu, Xavier
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Notes:
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The FLICE-inhibitory protein (FLIP) plays a key role in the regulation of apoptosis triggered by death ligands.
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been shown to induce apoptosis in some
types of tumor but not in others. To assess the possible role of FLIP in apoptosis resistance in endometrial
carcinoma, we performed an immunohistochemical study on a tissue microarray composed of 95 endometrial
carcinomas. We found positive signals in 43% of the cases, as well as a significant difference in FLIP
expression between stage I and II tumors. Moreover, we observed that endometrial carcinoma cell lines
Ishikawa and KLE did not undergo apoptosis after TRAIL treatment. Cotreatment of these cells with the inhibitor
of transcription actinomycin D resulted in a dramatic decrease in cell viability and induced activation of
caspase-8. These events coincided with downregulation of FLIP mRNA and protein. Inhibitors of caspase-8 or
overexpression of FLIP completely blocked apoptosis induced by actinomycin D plus TRAIL cotreatment. More
importantly, downregulation of endogenous FLIP expression by specific siRNAs sensitized endometrial
carcinoma cells to TRAIL-induced apoptosis in the absence of actinomycin D. Taken together, our results
suggest for the first time a critical role for FLIP in the regulation apoptosis triggered by TRAIL in endometrial
carcinoma cells.
This work was supported by Grants FISS 01/1656, FISS PI020227, SAF 2004-05250 and 2002XT00115. XD holds a postdoctoral fellowship supported by Department d’Universitats, Recerca i Societat de la Informació, Generalitat de Catalunya (2003RED0018). JP holds a research fellowship from the Fondo de Investigaciones Sanitarias, Ministerio de Sanidad y Consumo (BEFI-02/9007). The work was also supported by FIS (PI020051 and Redes de Investigación Cooperativa), Fundació La Caixa 2002 and Suport als Grups de Recerca (Generalitat de Catalunya). |
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Subject(s):
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-Endometrial carcinoma
-FLIP
-TRAIL
-Tissue microarray |
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Rights:
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(c) USCAP, Inc., 2005
info:eu-repo/semantics/restrictedAccess |
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Document type:
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article
publishedVersion |
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Published by:
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Nature Publishing Group
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