ABSTRACT
Inhibition of IRE1 (inositol requiring enzyme-1), the major signaling pathway of endoplasmic reticulm stress, significantly decreases glioma cell proliferation and tumor growth. We have studied the expression of TNFα-related genes and effect of glucose deprivation on these gene expressions in U87 glioma cells over-expressing dominant-negative IRE1 defective in both kinase and endonuclease (dn-IRE1) activity of IRE1 with hopes of elucidating its contribution to IRE1 mediated glioma growth. We have demonstrated that glucose deprivation condition leads to down-regulation of the expression of TNFRSF11B, TNFRSF1A, TNFRSF10D/TRAILR4, and LITAF genes and up-regulation of TNFRSF10B/TRAILR2/DR5 gene at the mRNA level in control glioma cells. At the same time, the expression of TNFRSF21/DR6, TNFAIP1, TNFAIP3, TRADD, and CD70/TNFSF7 genes in control glioma cells is resistant to glucose deprivation condition. The inhibition of IRE1 modifies the effect of glucose deprivation on LITAF, TNFRSF21, TNFRSF11B, and TRADD gene expressions and induces sensitivity to glucose deprivation condition the expression of TNFRSF10B, TNFRSF1A, and CD70 genes. We have also demonstrated that the expression of all studied genes is affected in glioma cells by inhibition of IRE1, except TNFRSF1A gene, as compared to control glioma cells. Moreover, the changes in the expression of TNFRSF1A, TNFRSF10D/TRAILR4, and LITAF genes induced by glucose deprivation condition have opposite orientation to that induced by inhibition of IRE1. The present study demonstrates that fine-tuning of the expression of TNFα-induced proteins and TNF receptor superfamily genes, which related to cell death and proliferation, is regulated by IRE1, an effector of endoplasmic reticulum stress, as well as depends on glucose deprivation in gene specific manner. Thus, the inhibition of kinase and endoribonuclease activity of IRE1 correlates with deregulation of TNFα-induced protein genes and TNF receptor superfamily genes in gene specific manner and thus slower the tumor growth.
Subject(s)
Endoplasmic Reticulum Stress/genetics , Endoribonucleases/genetics , Gene Expression Regulation, Neoplastic , Glucose/deficiency , Protein Serine-Threonine Kinases/genetics , RNA, Messenger/genetics , Tumor Necrosis Factor-alpha/genetics , Adaptor Proteins, Signal Transducing , CD27 Ligand/genetics , CD27 Ligand/metabolism , Cell Line, Tumor , Cell Proliferation , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Endoribonucleases/deficiency , Humans , Intracellular Signaling Peptides and Proteins/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Neuroglia/metabolism , Neuroglia/pathology , Nuclear Proteins/genetics , Nuclear Proteins/metabolism , Osteoprotegerin/genetics , Osteoprotegerin/metabolism , Protein Serine-Threonine Kinases/deficiency , Proteins/genetics , Proteins/metabolism , RNA, Messenger/metabolism , Receptors, TNF-Related Apoptosis-Inducing Ligand/genetics , Receptors, TNF-Related Apoptosis-Inducing Ligand/metabolism , Receptors, Tumor Necrosis Factor/genetics , Receptors, Tumor Necrosis Factor/metabolism , Receptors, Tumor Necrosis Factor, Type I/genetics , Receptors, Tumor Necrosis Factor, Type I/metabolism , Signal Transduction , TNF Receptor-Associated Death Domain Protein/genetics , TNF Receptor-Associated Death Domain Protein/metabolism , Transcription Factors/genetics , Transcription Factors/metabolism , Tumor Necrosis Factor Decoy Receptors/genetics , Tumor Necrosis Factor Decoy Receptors/metabolism , Tumor Necrosis Factor alpha-Induced Protein 3 , Tumor Necrosis Factor-alpha/metabolismABSTRACT
The endoplasmic reticulum stress is an important factor of tumor growth and is induced in cancer cells. We have studied the effect of ERN1 knockdown as well as hypoxia on the expression of genes encoding factors, which control cell proliferation, in U87 glioma cells. It was shown that the complete blockade of ERN1 enzyme function leads to an increase of the PLAT (tissue plasminogen activator), CCN2 (CCN family member 2), and ITGB1 (integrin ß-1) as well as to a decrease ofPLAU (plasminogen activator, urokinase), PLAUR (plasminogen activator, urokinase receptor), and SLURP1 (secreted LY6/PLAUR domain containing 1) mRNA expressions. Moreover, we have shown that hypoxia does not affect the expression level of ITGB1 mRNA, but increases that of CCN2, PLAUR, SLURP1, and PLAT mRNA and decreases the expression level of only PLAU mRNA in control glioma cells. At the same time, in ERN1 knockdown glioma cells the expression level of PLAU PLAUR, and SLURP1 mRNA is decreased under hypoxia, but PLAT and ITGB1 mRNA expression levels are increased under these experimental conditions. Thus, results of this study have shown that the expression level of all studied genes is affected by ERN1 knockdown as well as by hypoxia and that the effect of hypoxia mostly depends on ERN1 signaling enzyme function.
Subject(s)
Cell Proliferation/genetics , Endoplasmic Reticulum Stress/genetics , Endoribonucleases/genetics , Gene Expression Regulation , Protein Serine-Threonine Kinases/genetics , RNA, Messenger/genetics , Cell Hypoxia/genetics , Cell Line, Tumor , Gene Knockdown Techniques , Humans , Microscopy, Phase-ContrastABSTRACT
We have studied the effect of acute L-glutamine deprivation on the expression oftumor protein 53 (TP53)-related genes such as TOPORS (topoisomerase I binding, arginine/serine-rich, E3 ubiquitin protein ligase), TP53BPI (TP53 bindingprotein 1), TP53TG1 (TP53 inducible gene 1), SESN1 (p53 regulatedPA26 nuclear protein), NME6 (NME/NM23 nucleoside diphosphate kinase 6), and ZMAT3 (zinc finger Matrin-type 3) in glioma cells with ERN1 knockdown. It was shown that blockade of ERN1 finction in U87 glioma cells is induced the expression of RYBP and SESN1 genes, but decreased the expression of TP53BP1, TP53TG1, TOPORS, NME6, genes. Moreover, the expression levels ofRYBPI SESN1, TP53BP1, and ZMAT3 genes is increased in control glioma cells by L-glutamine deprivation condition but blockade of ERN1 signaling enzyme function significantly enhances this effect on the expression all of these genes. At the same time, the ERN1 knockdown eliminates the response TP53TG1 and TOPORS genes to L-glutamine deprivation condition. Results of this investigation clearly demonstrate that the expression most of genes encoding TP53-related factors depends upon acute L-glutamine deprivation condition as well as upon ERN1, the major signaling system of the endoplasmic reticulum stress.
