کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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3299220 | 1209924 | 2006 | 12 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: All-Trans Retinoic Acid Induces XAF1 Expression Through an Interferon Regulatory Factor-1 Element in Colon Cancer All-Trans Retinoic Acid Induces XAF1 Expression Through an Interferon Regulatory Factor-1 Element in Colon Cancer](/preview/png/3299220.png)
Background & Aims: X-linked inhibitor of apoptosis protein (XIAP)-associated factor 1 (XAF1) is a novel tumor suppressor and interferon (IFN)-stimulated gene. All-trans retinoic acid (ATRA) exerts an antiproliferative effect on tumor cells through up-regulation of IFN regulatory factor 1 (IRF-1) and the downstream IFN-stimulated genes. The aim of this study was to determine the effect and mechanism of ATRA on XAF1 expression and the role of XAF1 in ATRA-induced growth inhibition in colon cancer. Methods: Gene expression is detected by reverse-transcription polymerase chain reaction and immunoblotting. The transcription activity of XAF1 promoter is examined by luciferase reporter assay. The activity of IFN regulatory factor binding element (IRF-E) is assessed by electrophoretic mobility shift assay and chromatin immunoprecipitation assay. Cell growth is evaluated by both in vitro and in vivo in nude mice xenografts. Results: IFN-alfa stimulates XAF1 promoter activity in the colon cancer cells Lovo and SW1116 dose-dependently. An IRF-1 binding element (IRF-E–XAF1) is found in the -30 to -38 nucleotide region upstream of the ATG initiator codon of the XAF1 gene. Site-directed mutagenesis of IRF-E–XAF1 abrogates native and IFN-induced promoter activity and binding capacity. ATRA induces XAF1 expression both in vitro and in vivo through interaction with IRF-E–XAF1. Overexpression of XAF1 increases cell susceptibility to ATRA-induced growth suppression both in vitro and in vivo. Furthermore, the effect of ATRA on XAF1 expression is independent of the promoter methylation and the subcellular distribution of XIAP. Conclusions: XAF1 participates in ATRA-induced growth suppression through IRF-1–mediated transcriptional regulation.
Journal: Gastroenterology - Volume 130, Issue 3, March 2006, Pages 747–758