RESUMO
OBJECTIVE: The aim of the present study was to examine the effect of chromium disilicide and titanium nitride nanoparticles on the expression level of genes encoding important regulatory factors (IGFBP1, IGFBP2, IGFBP3, IGFBP4, IGFBP5, SNARK/NUAK2, CD36, and PECAM1/CD31) in mouse liver for evaluation of possible toxic effects of these nanoparticles. METHODS: Male mice received 20 mg chromium disilicide nanoparticles (45 nm) and titanium nitride nanoparticles (20 nm) with food every working day for 2 months. The expression of IGFBP1, IGFBP2, IGFBP3, IGFBP4, IGFBP5, SNARK, CD36, and PECAM1 genes in mouse liver was studied by quantitative polymerase chain reaction. RESULTS: Treatment of mice with chromium disilicide nanoparticles led to down-regulation of the expression of IGFBP2, IGFBP5, PECAM1, and SNARK genes in the liver in comparison with control mice, with more prominent changes for SNARK gene. At the same time, the expression of IGFBP3 and CD36 genes was increased in mouse liver upon treatment with chromium disilicide nanoparticles. We have also shown that treatment with titanium nitride nanoparticles resulted in down-regulation of the expression of IGFBP2 and SNARK genes in the liver with more prominent changes for SNARK gene. At the same time, the expression of IGFBP3, IGFBP4, and CD36 genes was increased in the liver of mice treated with titanium nitride nanoparticles. Furthermore, the effect of chromium disilicide nanoparticles on IGFBP2 and CD36 genes expression was significantly stronger as compared to titanium nitride nanoparticles. CONCLUSIONS: The results of this study demonstrate that chromium disilicide and titanium nitride nanoparticles have variable effects on the expression of IGFBP2, IGFBP3, IGFBP4, IGFBP5, SNARK, CD36, and PECAM1 genes in mouse liver, which may reflect the genotoxic activities of the studied nanoparticles.
Assuntos
Expressão Gênica/efeitos dos fármacos , Fígado/efeitos dos fármacos , Nanopartículas , RNA Mensageiro/efeitos dos fármacos , Titânio/farmacologia , Animais , Antígenos CD36/efeitos dos fármacos , Antígenos CD36/genética , Compostos de Cromo/farmacologia , Regulação para Baixo , Proteína 1 de Ligação a Fator de Crescimento Semelhante à Insulina/efeitos dos fármacos , Proteína 1 de Ligação a Fator de Crescimento Semelhante à Insulina/genética , Proteína 2 de Ligação a Fator de Crescimento Semelhante à Insulina/efeitos dos fármacos , Proteína 2 de Ligação a Fator de Crescimento Semelhante à Insulina/genética , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/efeitos dos fármacos , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/genética , Proteína 4 de Ligação a Fator de Crescimento Semelhante à Insulina/efeitos dos fármacos , Proteína 4 de Ligação a Fator de Crescimento Semelhante à Insulina/genética , Fígado/metabolismo , Masculino , Camundongos , Molécula-1 de Adesão Celular Endotelial a Plaquetas/efeitos dos fármacos , Molécula-1 de Adesão Celular Endotelial a Plaquetas/genética , Reação em Cadeia da Polimerase , Proteínas Serina-Treonina Quinases/efeitos dos fármacos , Proteínas Serina-Treonina Quinases/genética , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Compostos de Silício/farmacologia , Regulação para CimaRESUMO
OBJECTIVE: The aim of the present investigation was to examine the effect of inhibition of endoplasmic reticulum stress signaling, mediated by IRE1 (inositol requiring enzyme 1), which is a central mediator of the unfolded protein response on the expression of genes encoding glucocorticoid receptor (NR3C1) and some related proteins (SGK1, SGK3, NCOA1, NCOA2, ARHGAP35, NNT) and their hypoxic regulation in U87 glioma cells for evaluation of their possible significance in the control of the glioma growth. METHODS: The expression of NR3C1,SGK1,SGK3, NCOA1, NCOA2, ARHGAP35, and NNT genes in U87 glioma cells, transfected by empty vector pcDNA3.1 (control) and cells without IRE1 signaling enzyme function (transfected by dnIRE1) upon hypoxia, was studied by quantitative polymerase chain reaction. RESULTS: Inhibition of IRE1 signaling enzyme function up-regulates the expression of NR3C1, SGK1, NCOA1, NCOA2, ARHGAP35, and NNT genes in U87 glioma cells in comparison with the control glioma cells, with more significant changes for NR3C1, SGK1, and NNT genes. At the same time, the expression of SGK3 gene is strongly down-regulated in glioma cells upon inhibition of IRE1. We have also shown that hypoxia increases the expression of NR3C1, SGK1, NCOA2, ARHGAP35, and NNT genes but decreases SGK3 and NCOA1 genes expression in control glioma cells. Moreover, the inhibition of both enzymatic activities (kinase and endoribonuclease) of IRE1 in U87 glioma cells enhances the eff ect of hypoxia on the expression of SGK1, SGK3, and NNT genes, but decreases the sensitivity of NR3C1 gene to hypoxic condition. Furthermore, the expression of NCOA1 gene is resistant to hypoxia in control glioma cells, but NCOA2 and ARHGAP35 genes are resistant to this condition in glioma cells without functional activity of IRE1 signaling enzyme. CONCLUSIONS: Results of this investigation demonstrate that inhibition of IRE1 signaling enzyme function affects the expression of NR3C1, SGK1, SGK3, NCOA1, NCOA2, ARHGAP35, and NNT genes in U87 glioma cells in gene specific manner and that all these genes are regulated by hypoxia preferentially through IRE1 signaling pathway of the endoplasmic reticulum stress.
Assuntos
Neoplasias Encefálicas/metabolismo , Endorribonucleases/metabolismo , Glioma/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Receptores de Glucocorticoides/metabolismo , Transdução de Sinais , Neoplasias Encefálicas/genética , Hipóxia Celular , Linhagem Celular Tumoral , Endorribonucleases/genética , Regulação Enzimológica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Glioma/genética , Humanos , Proteínas Serina-Treonina Quinases/genética , Receptores de Glucocorticoides/genética , TransfecçãoRESUMO
We have studied the effect of inhibition of IRE1 (inositol requiring enzyme 1), which is a central mediator of endoplasmic reticulum stress and a controller of cell proliferation and tumor growth, on hypoxic regulation of the expression of different proliferation related genes in U87 glioma cells. It was shown that hypoxia leads to up-regulation of the expression of IL13RA2, CD24, ING1, ING2, ENDOG, and POLG genes and to down-regulation of KRT18, TRAPPC3, TSFM, and MTIF2 genes at the mRNA level in control glioma cells. Changes for ING1 and CD24 genes were more significant. At the same time, inhibition of IRE1 modifies the effect of hypoxia on the expression of all studied genes. In particular, it increases sensitivity to hypoxia of the expression of IL13RA2, TRAPPC3, ENDOG, and PLOG genes and suppresses the effect of hypoxia on the expression of ING1 gene. Additionally, it eliminates hypoxic regulation of KRT18, CD24, ING2, TSFM, and MTIF2 genes expressions and introduces sensitivity to hypoxia of the expression of BET1 gene in glioma cells. The present study demonstrates that hypoxia, which often contributes to tumor growth, affects the expression of almost all studied genes. Additionally, inhibition of IRE1 can both enhance and suppress the hypoxic regulation of these gene expressions in a gene specific manner and thus possibly contributes to slower glioma growth, but several aspects of this regulation must be further clarified.
Assuntos
Estresse do Retículo Endoplasmático/genética , Endorribonucleases/genética , Regulação Neoplásica da Expressão Gênica , Neuroglia/metabolismo , Proteínas Serina-Treonina Quinases/genética , RNA Mensageiro/genética , Transdução de Sinais/genética , Antígeno CD24/genética , Antígeno CD24/metabolismo , Hipóxia Celular , Linhagem Celular Tumoral , Proliferação de Células , DNA Polimerase gama/genética , DNA Polimerase gama/metabolismo , Endodesoxirribonucleases/genética , Endodesoxirribonucleases/metabolismo , Endorribonucleases/antagonistas & inibidores , Endorribonucleases/metabolismo , Fatores de Iniciação em Eucariotos/genética , Fatores de Iniciação em Eucariotos/metabolismo , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Humanos , Proteína 1 Inibidora do Crescimento/genética , Proteína 1 Inibidora do Crescimento/metabolismo , Subunidade alfa2 de Receptor de Interleucina-13/genética , Subunidade alfa2 de Receptor de Interleucina-13/metabolismo , Queratina-18/genética , Queratina-18/metabolismo , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Neuroglia/patologia , Fatores de Alongamento de Peptídeos/genética , Fatores de Alongamento de Peptídeos/metabolismo , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Qc-SNARE/genética , Proteínas Qc-SNARE/metabolismo , RNA Mensageiro/metabolismo , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo , Proteínas de Transporte Vesicular/genética , Proteínas de Transporte Vesicular/metabolismoRESUMO
We have studied the effect of hypoxia on the expression of nuclear genes encoding mitochondrial proteins in U87 glioma cells under the inhibition of IRE1 (inositol requiring enzyme-1), which controls cell proliferation and tumor growth as a central mediator of endoplasmic reticulum stress. It was shown that hypoxia down-regulated gene expression of malate dehydrogenase 2 (MDH2), malic enzyme 2 (ME2), mitochondrial aspartate aminotransferase (GOT2), and subunit B of succinate dehydrogenase (SDHB) in control (transfected by empty vector) glioma cells in a gene specific manner. At the same time, the expression level of mitochondrial NADP+-dependent isocitrate dehydrogenase 2 (IDH2) and subunit D of succinate dehydrogenase (SDHD) genes in these cells does not significantly change in hypoxic conditions. It was also shown that the inhibition of ÐRE1 signaling enzyme function in U87 glioma cells decreases the effect of hypoxia on the expression of ME2, GOT2, and SDHB genes and introduces the sensitivity of IDH2 gene to hypoxia. Furthermore, the expression of all studied genes depends on IRE1-mediated endoplasmic reticulum stress signaling in gene specific manner, because ÐRE1 knockdown significantly decreases their expression in normoxic conditions, except for IDH2 gene, which expression level is strongly up-regulated. Therefore, changes in the expression level of nuclear genes encoding ME2, MDH2, IDH2, SDHB, SDHD, and GOT2 proteins possibly reflect metabolic reprogramming of mitochondria by hypoxia and IRE1-mediated endoplasmic reticulum stress signaling and correlate with suppression of glioma cell proliferation under inhibition of the IRE1 enzyme function.
Assuntos
Núcleo Celular/genética , Estresse do Retículo Endoplasmático/genética , Endorribonucleases/genética , Regulação Neoplásica da Expressão Gênica , Mitocôndrias/genética , Neuroglia/enzimologia , Proteínas Serina-Treonina Quinases/genética , Aspartato Aminotransferases/genética , Aspartato Aminotransferases/metabolismo , Hipóxia Celular , Linhagem Celular Tumoral , Núcleo Celular/enzimologia , Proliferação de Células , Endorribonucleases/deficiência , Humanos , Isocitrato Desidrogenase/genética , Isocitrato Desidrogenase/metabolismo , Malato Desidrogenase/genética , Malato Desidrogenase/metabolismo , Mitocôndrias/enzimologia , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Neuroglia/patologia , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteínas Serina-Treonina Quinases/deficiência , Transporte Proteico , Transdução de Sinais , Succinato Desidrogenase/genética , Succinato Desidrogenase/metabolismoRESUMO
Tumor necrosis factor (TNF) superfamily receptors and TNF apoptosis inducing ligands play an important role in the realization of TNF function and control tumor growth. The TNF-related pathways are controlled by endoplasmic reticulum stress signaling, which has a crucial role in the control of cell proliferation and tumor growth. Furthermore, the inhibition of IRE1 (inositol requiring enzyme-1), which is a central mediator of endoplasmic reticulum stress sand mainly responsible for cell proliferation and apoptosis, leads to suppression of tumor growth through specific changes in the expression of genes encoding transcription factors, tumor suppressors, angiogenesis and apoptosis related proteins, including TNF superfamily receptors and TNF apoptosis inducing ligands. Therefore, changes in the expression level of TNF-related genes encoding TNF superfamily receptors and apoptosis inducing ligands possibly reflect metabolic reprogramming of cancer cells upon inhibition of IRE1-mediated endoplasmic reticulum stress signaling and correlate with suppression of glioma cell proliferation.
Assuntos
Apoptose/genética , Neoplasias Encefálicas/genética , Endorribonucleases/genética , Regulação Neoplásica da Expressão Gênica , Glioma/genética , Proteínas Serina-Treonina Quinases/genética , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/genética , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Proliferação de Células , Estresse do Retículo Endoplasmático/genética , Endorribonucleases/deficiência , Glioma/metabolismo , Glioma/patologia , Humanos , Proteínas Serina-Treonina Quinases/deficiência , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Transdução de Sinais , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismoRESUMO
We investigated the impact of IRE1/ERN1 (inositol requiring enzyme 1/endoplasmic reticulum to nucleus signaling 1) knockdown on hypoxic regulation of the expression of a subset of proliferation and migration-related genes in U87 glioma cells. It was shown that hypoxia leads to up-regulation of the expression of MEST and SNAI2, to down-regulation of MYBL1, TCF8 and GTF2F2 genes at the mRNA level in control glioma cells. At the same time hypoxia did not affect the expression of TCF3 and GTF2B transcription factor genes. In turn, inhibition of IRE1 modified the effect of hypoxia on the expression of all studied genes, except MYBL1 and GTF2B. For instance, IRE1 knockdown decreased sensitivity to hypoxia of the expression of MEST, TCF8 and SNAI2 genes and increased sensitivity to hypoxia of GTF2F2 expression. At the same time, IRE1 inhibition introduced sensitivity to hypoxia of the expression of TCF3 gene in glioma cells. The present study demonstrated that the inhibition of IRE1 in glioma cells affected the hypoxic regulation of the expression of studied genes in various directions, though hypoxic conditions did not abolish the effect of IRE1 inhibition on the expression of respective genes. To the contrary, in case of SNAI2, GTF2F2 and MEST hypoxic conditions magnified the effect of IRE1 inhibition on the expression of respective genes in glioma cells.
Assuntos
Estresse do Retículo Endoplasmático/genética , Endorribonucleases/genética , Regulação Neoplásica da Expressão Gênica , Neuroglia/metabolismo , Proteínas Serina-Treonina Quinases/genética , RNA Mensageiro/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Hipóxia Celular , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Endorribonucleases/deficiência , Técnicas de Silenciamento de Genes , Humanos , Neuroglia/patologia , Proteínas Serina-Treonina Quinases/deficiência , Proteínas/genética , Proteínas/metabolismo , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , RNA Mensageiro/metabolismo , Transdução de Sinais , Fatores de Transcrição da Família Snail/genética , Fatores de Transcrição da Família Snail/metabolismo , Proteína de Ligação a TATA-Box/genética , Proteína de Ligação a TATA-Box/metabolismo , Transativadores/genética , Transativadores/metabolismo , Fatores de Transcrição TFII/genética , Fatores de Transcrição TFII/metabolismoRESUMO
Glycolysis and glutaminolysis as well as endoplasmic reticulum stress are required for tumor progression suggests through regulation of the cell cycle. Inhibition of ERN1/IRE1 (endoplasmic reticulum to nucleus signaling 1/inositol requiring enzyme 1), a central mediator of endoplasmic reticulum stress, significantly suppresses glioma cell proliferation and tumor growth as well as modifies sensitivity gene expressions to glucose and glutamine deprivation. We have studied the expression of genes encoded transcription factors such as E2F8 (E2F transcription factor 8), EPAS1 (endothelial PAS domain protein 1), HOXC6 (homeobox C6), TBX3 (T-box 3), TBX2 (T-box 2), GTF2F2 (general transcription factor IIF), GTF2B (general transcription factor IIB), MAZ (MYC-associated zinc finger protein, purine-binding transcription factor), SNAI2 (snail family zinc finger 2), TCF3 (transcription factor 3), and TCF8/ZEB1 (zinc finger E-box binding homeobox 1)in U87 glioma cells upon glucose and glutamine deprivation in relation to inhibition of IRE1.We demonstrated that glutamine deprivation leads to up-regulation of the expression of EPAS1, TBX3, GTF2B, and MAZ genes and down-regulation of E2F8, GTF2F2, TCF8, and TBX2 genes in control glioma cells.At the same time, glucose deprivation enhances the expression of EPAS1 and GTF2B genes and decreases of E2F8, HOXC6, TCF3, and TBX2 genes in these glioma cells. Inhibition of IRE1 by dnIRE1 significantly modifies the expression most of studied genes with different magnitude. Present study demonstrates that fine-tuning of the expression of proliferation related transcription factor genes depends upon glucose and glutamine deprivation in IRE1-dependent manner and possibly contributes to slower tumor growth after inhibition of IRE1.
Assuntos
Estresse do Retículo Endoplasmático/genética , Endorribonucleases/genética , Regulação Neoplásica da Expressão Gênica , Glucose/deficiência , Glutamina/deficiência , Neuroglia/metabolismo , Proteínas Serina-Treonina Quinases/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Ciclo Celular/genética , Hipóxia Celular , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Endorribonucleases/deficiência , Técnicas de Silenciamento de Genes , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Humanos , Neuroglia/patologia , Proteínas Serina-Treonina Quinases/deficiência , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Transdução de Sinais , Fatores de Transcrição da Família Snail/genética , Fatores de Transcrição da Família Snail/metabolismo , Proteínas com Domínio T/genética , Proteínas com Domínio T/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Fatores de Transcrição TFII/genética , Fatores de Transcrição TFII/metabolismo , Homeobox 1 de Ligação a E-box em Dedo de Zinco/genética , Homeobox 1 de Ligação a E-box em Dedo de Zinco/metabolismoRESUMO
OBJECTIVE: The aim of the present study was to investigate the effect of inhibition of endoplasmic reticulum stress signaling mediated by IRE1/ERN1 (inositol-requiring enzyme 1/endoplasmic reticulum to nucleus signaling 1) on the expression of genes encoding different groups of insulin-like growth binding proteins (IGFBP6 and IGFBP7) and CCN family (IGFBP8/CTGF/CCN2, IGFBP9/NOV/CCN3, IGFBP10/CYR61/CCN1, WISP1/CCN4, and WISP2/CCN5) and its sensitivity to glucose deprivation in U87 glioma cells. METHODS: The expression of IGFBP6, IGFBP7, IGFBP8, IGFBP9, IGFBP10, WISP1, and WISP2 genes was studied by qPCR in control U87 glioma cells (wild-type) and its subline with IRE1 signaling enzyme loss of function upon glucose deprivation. RESULTS: The expression of IGFBP8, IGFBP9, and WISP2 genes was up-regulated in control glioma cells upon glucose deprivation with most significant changes for IGFBP9 gene. At the same time, the expression of IGFBP6, IGFBP10, and WISP1 genes was resistant to glucose deprivation in these glioma cells, but the IGFBP7 gene expression was down-regulated. The inhibition of both enzymatic activities (kinase and endoribonuclease) of IRE1 in glioma cells modified the sensitivity of most studied gene expressions to glucose deprivation condition: introduced sensitivity of IGFBP10 and WISP1 genes to glucose deprivation, enhanced the effect of this deprivation on IGFBP7 and IGFBP9 gene expressions, and reduced this effect on WISP2 gene and induced suppressive effect of glucose deprivation on the expression of IGFBP8 gene. Furthermore, the inhibition of IRE1 strongly affected the expression of all studied genes in glioma cells upon regular growing condition in gene specific manner: up-regulated the expression levels of IGFBP7, IGFBP8, IGFBP10, WISP1, and WISP2 genes and down-regulated the IGFBP6 and IGFBP9 genes. CONCLUSIONS: The data of this investigation demonstrate that the expression of IGFBP7, IGFBP8, IGFBP9, and WISP2 genes are sensitive to glucose deprivation in U87 glioma cells and that inhibition of IRE1 signaling enzyme function may significantly affect the expression of all studied genes in the presence of glucose as well as modify the effect of glucose deprivation on the expression of most studied genes. These data also show that proteins encoded by these genes may participate in the regulation of metabolic and proliferative processes via IGF/INS receptors and possibly other signaling pathways as well, via IRE1 signaling, which is a central mediator of the unfolded protein response and an important component of the tumor growth and metabolic diseases.
Assuntos
Neoplasias Encefálicas/enzimologia , Endorribonucleases/deficiência , Glioma/enzimologia , Glucose/deficiência , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/metabolismo , Proteínas Serina-Treonina Quinases/deficiência , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Proteínas de Sinalização Intercelular CCN/genética , Proteínas de Sinalização Intercelular CCN/metabolismo , Linhagem Celular Tumoral , Endorribonucleases/genética , Regulação Neoplásica da Expressão Gênica , Glioma/genética , Glioma/patologia , Humanos , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/genética , Proteínas Serina-Treonina Quinases/genética , RNA Mensageiro/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Transdução de Sinais , TransfecçãoRESUMO
Hypoxia as well as the endoplasmic reticulum stress are important factors of malignant tumor growth and control of the expression of genes, which regulate numerous metabolic processes and cell proliferation. Furthermore, blockade of ERN1 (endoplasmic reticulum to nucleus 1) suppresses cell proliferation and tumor growth. We studied the effect of hypoxia on the expression of genes encoding the transcription factors such as E2F8 (E2F transcription factor 8), EPAS1 (endothelial PAS domain protein 1), TBX3 (T-box 3), ATF3 (activating transcription factor 3), FOXF1 (forkhead box F), and HOXC6 (homeobox C6) in U87 glioma cells with and without ERN1 signaling enzyme function. We have established that hypoxia enhances the expression of HOXC6, E2F8, ATF3, and EPAS1 genes but does not change TBX3 and FOXF1 gene expression in glioma cells with ERNI function. At the same time, the expression level of all studied genes is strongly decreased, except for TBX3 gene, in glioma cells without ERN1 function. Moreover, the inhibition of ERN1 signaling enzyme function significantly modifies the effect of hypoxia on the expression of these transcription factor genes. removes or introduces this regulation as well as changes a direction or magnitude of hypoxic regulation. Present study demonstrates that fine-tuning of the expression of proliferation related genes depends upon hypoxia and ERN1-mediated endoplasmic reticulum stress signaling and correlates with slower proliferation rate of glioma cells without ERN1 function.
Assuntos
Endorribonucleases/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Neuroglia/efeitos dos fármacos , Oxigênio/farmacologia , Proteínas Serina-Treonina Quinases/genética , Transdução de Sinais/efeitos dos fármacos , Fator 3 Ativador da Transcrição/genética , Fator 3 Ativador da Transcrição/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Hipóxia Celular/genética , Linhagem Celular Tumoral , Proliferação de Células , Estresse do Retículo Endoplasmático/genética , Endorribonucleases/antagonistas & inibidores , Endorribonucleases/metabolismo , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/metabolismo , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Humanos , Neuroglia/metabolismo , Neuroglia/patologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Proteínas com Domínio T/genética , Proteínas com Domínio T/metabolismo , TransfecçãoRESUMO
Activation of pentose phosphate pathway is an important factor of enhanced cell proliferation and tumor growth. Phosphoribosyl pyrophosphate synthetase (PRPS) is a key enzyme of this pathway and plays a central role in the synthesis of purines and pyrimidines. Hypoxia as well as ERN1 (from endoplasmic reticulum to nuclei-1) mediated endoplasmic reticulum stress response-signalling pathway is linked to the proliferation because the blockade of ERN1 suppresses tumor growth, including glioma. We studied the expression of different PRPS genes in glioma cells with ERN1 knockdown under hypoxic condition. It was shown that hypoxia decreases the expression of PRPS1 and PRPS2 genes in both types of glioma cells, being more pronounced in cells without ERN1 function, but PRPSAP1 and PRPSAP2 gene expressions are suppressed by hypoxia only in glioma cells with blockade of ERN1. Moreover, the blockade of endoribonuclease activity of ERN1 does not affect the expression of PRPS1 and PRPS2 as well as PPRS-associated protein genes in U87 glioma cells. At the same time, the induction of endoplasmic reticulum stress by tunicamycin in glioma cells with suppressed activity of ERN1 endoribonuclease decreases the expression level of PRPS1 and PRPS2 genes only. Results of this investigation clearly demonstrated that the expression of different genes encoding subunits of PRPS enzyme is affected by hypoxia in U87 glioma cells, but the effect of hypoxia is modified by suppression of endoplasmic reticulum stress signaling enzyme ERN1.
