ABSTRACT
BACKGROUND: Insulin decreases the incidence of sepsis and improves mortality of critically ill patients. In endotoxemic as well as in thermally injured rats, insulin attenuates the systemic inflammatory response by decreasing the proinflammatory and increasing the antiinflammatory cascade. The aim of the present study was to determine the effects of insulin on cell survival, cell activity, apoptosis, and proinflammatory response in a human macrophage-like cell line (THP-1 cells) stressed with lipopolysaccharide (LPS). MATERIALS AND METHODS: Human macrophages were stressed with LPS and received either saline or insulin. Cell viability was analyzed by MTS, apoptosis was detected using JC-1 and terminal deoxynucleotidyl transferase-mediated nick end labeling-staining, and to elucidate on the signaling pathway, we used wortmannin as a phosphatidylinositol-3-kinase inhibitor. Tumor necrosis factor (TNF) and interleukin-1beta (IL-1beta) were measured to determine the effect of insulin on proinflammatory cytokine expression. RESULTS: Insulin caused a significant increase in cell viability and significantly reduced apoptosis in LPS-stimulated human macrophages in a dose-dependent manner. The antiapoptotic effect of insulin could be completely blocked with the addition of wortmannin. Insulin significantly decreased TNF and IL-1beta in endotoxemic human macrophages. CONCLUSIONS: Our results indicate that insulin exerts antiapoptotic effects and reduces the expression of proinflammatory cytokines in endotoxemic human macrophages. The antiapoptotic effects are mediated via the phospatidylinositol-3-kinase-pathway.
Subject(s)
Anti-Inflammatory Agents/pharmacology , Endotoxemia/drug therapy , Hypoglycemic Agents/pharmacology , Insulin/pharmacology , Macrophages/drug effects , Androstadienes/pharmacology , Apoptosis/drug effects , Apoptosis/immunology , Cell Line , Cell Survival/drug effects , Cell Survival/immunology , Cytokines/metabolism , Endotoxemia/immunology , Humans , Insulin Antagonists/pharmacology , Lipopolysaccharides/pharmacology , Macrophages/immunology , Macrophages/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Signal Transduction/drug effects , Signal Transduction/immunology , WortmanninABSTRACT
PURPOSE: Microarray technology has been used by a growing number of investigators and several studies have been published that list hundreds of genes differentially expressed by colorectal carcinoma (CRC) and normal mucosa (MC). On the basis of our own and other investigators' microarray data, our goal was to identify a common denominator gene cluster distinguishing CRC from MC. METHODS: Thirty GeneChips (HG-U133A, Affymetrix) were hybridized, 20 with RNA of CRC stages I-IV (UICC) and 10 with MC. Expression signals showing at least a 4-fold difference between CRC and MC (p<0.01) were identified as differentially expressed. In addition, in our integrative data analysis approach only those genes whose expression was altered simultaneously in at least 2 of 5 recently published studies were subjected to an unsupervised hierarchical cluster analysis. RESULTS: We detected 168 up- and 283 down-regulated genes in CRC relative to MC. Twenty-three genes were filtered from the five articles reviewed. An unsupervised hierarchical cluster analysis of these 23 genes confirmed the high specificity of these genes to differentiate between CRC and MC in our microarray data. CONCLUSIONS: Colorectal cancer and mucosa could be clearly separated by 23 genes selected for being differentially expressed more than once in a recent literature review. These genes represent a common denominator gene cluster that can be used to distinguish colorectal MC from CRC.
