ABSTRACT
<p><b>OBJECTIVE</b>To investigate the expressions of X-linked inhibitor of apoptosis protein (XIAP)-associated factor-1 (XAFI) and heat-shock transcription factor 1 (HSF1) and their relationship in human gastrointestinal cancers.</p><p><b>METHODS</b>Immunoblotting was used to analyze the expressions of HSF1 and XAF1 in gastric and colon cancer tissues and in gastrointestinal cancer cells. The gastrointestinal cancer cells were tranfected with a eukaryotic expression vector containing HSF1 gene fragment or subjected to RNA interference to induce up- or down-regulation of HSF1 expression, and the consequence changes in XAF1 expression in the cells was measured. XAF1 expression was also assayed in the cells after stress stimulation for HSF1 expression.</p><p><b>RESULTS</b>The expression of HSF1 was higher in gastrointestinal cancer tissues than in normal tissues. The expression of XAF1 and HSF1 was inversely correlated in the cancer cell lines, and stress stimuli of the cells up-regulated the expression of HSF1 but down-regulated XAF1 expression.</p><p><b>CONCLUSION</b>HSF1 expression is increased in gastrointestinal cancer tissues to result in suppressed expression of XAF1, which may be one of the reasons for the low expression of XAF1 in association with the defect of the apoptosis mechanisms in the cancer cells</p>
Subject(s)
Humans , Cell Line, Tumor , Colonic Neoplasms , Genetics , Metabolism , Pathology , DNA-Binding Proteins , Genetics , Heat Shock Transcription Factors , Immunoblotting , Intracellular Signaling Peptides and Proteins , Neoplasm Proteins , Genetics , RNA Interference , Stomach Neoplasms , Genetics , Metabolism , Pathology , Transcription Factors , Genetics , TransfectionABSTRACT
<p><b>OBJECTIVE</b>X-linked inhibitor of apoptosis protein (XIAP) To gastrointestinal (GI) investigate the expression of XAF1 and heat-shock transcription factors 1 èHSF1éand their relationship in human gastrointestinal cancers.</p><p><b>METHODS</b>Immunoblotting was used to analyze the expression of HSF1 and XAF1 in either gastric or colon cancer tissue and GI cancer cell line. Transient expression of the HSF1-containing vector in GI cell lines and RNA interference were used to up/down-regulae the expression of the HSF1, and the subsequent expression of XAF1 was measured.</p><p><b>RESULTS</b>The expression of HSF1 was higher in GI cancers than in normal tissues. The expression of XAF1 and HSF1 was negatively correlated in GI cancer cell lines. Stress stimuli up-regulated the expression of HSF1 while the alteration of XAF1 expression was negatively correlated with HSF1 expression.</p><p><b>CONCLUSION</b>The high expression of HSF1 in GI cancers is associated with suppressed expression of XAF1, which can be one of the mechanisms for low-expression of XAF1 and insufficient apoptosis in GI cancers.</p>