Expression of anti-angiogenic genes in subcutaneous adipose tissue of the obese individuals with pre-diabetes and type 2 diabetes

Accumulating evidence raises the hypothesis that dysregulation of different intrinsic mechanisms which control most metabolic processes are involved in the development of obesity, metabolic syndrome and type 2 diabetes mellitus, the most profound public health problems. Angiogenesis is an important component of different proliferative processes, in particular, fat tissue growth. Moreover, dysregulation of molecular components of the angiogenesis system can contributes to the development of diabetic complications. We have studied the expression levels of genes related to regulation of angiogenesis (TIMP1, TIMP2, TIMP3, TIMP4, THBS1, THBS2, THBS3, ADAMTS5, LUM, DCN, IL6 and ZEB1) in subcutaneous adipose tissue of obese individuals as well as obese patients with impaired glucose tolerance (prediabetic) and type 2 diabetes using real-time quantitative PCR. We have shown that the expression level of most of these genes with anti-angiogenic properties significantly increases in subcutaneous adipose tissue of obese individuals versus lean patients, being more intense for TIMP1, TIMP2, THBS2 and LUM genes. Increased expression level of TIMP1, TIMP2, TIMP3, ADAMTS5 as well as THBS1 and THBS2 in adipose tissue was found in obese patients with impaired glucose tolerance. At the same time, expression of genes which encode for TIMP1 and TIMP2 strongly decreased in adipose tissue of obese individuals with type 2 diabetes versus subjects with glucose intolerance. Results of this study provide strong evidence that expression of genes mostly related to suppression of angiogenesis is dysregulated in adipose tissue of obese individuals as well as in obese patients with glucose intolerance and type 2 diabetes. It is possible that these changes in the expression of TIMP and THBS genes in adipose tissue in obesity as well as in obese individuals with impaired glucose tolerance and type 2 diabetes can contribute to fat tissue storage, insulin resistance and the development of diabetic complications

Inhibition of IRE1 modifies the hypoxic regulation of GADD family gene expressions in U87 glioma cells

We have studied hypoxic regulation of the expression of genes encoded GADD (growth arrest and DNA damage) family proteins in U87 glioma cells in relation to inhibition of IRE1 (inositol requiring enzyme-1), which controls cell proliferation and tumor growth as a central mediator of endoplasmic reticulum stress. We have shown that hypoxia up-regulates the expression of GADD34, GADD45A, GADD45B, and GADD153 genes, which are related to cell proliferation and apoptosis, in control (transfected by empty vector) glioma cells in gene specific manner. At the same time, the expression level of EIF2AK1 (eukaryotic translation initiation factor 2-alpha kinase 1) and AIFM1 (apoptosis inducing factor, mitochondria associated 1) genes in these cells is down-regulated upon hypoxic condition. It was also shown that inhibition of ІRE1 signaling enzyme function in U87 glioma cells enhances the effect of hypoxia on these genes expression, except EIF2AK1 and AIFM1 genes. Furthermore, the expression of all studied genes in ІRE1 knockdown cells is significantly decreased upon normoxic condition, except GADD45B gene, which expression level is strongly up-regulated. Therefore, the expression level of genes encoding GADD34, GADD45A, GADD45B, GADD153, EIF2AK1, and AIFM1 is affected by hypoxia and by inhibition of IRE1-mediated endoplasmic reticulum stress signaling in gene specific manner and correlates with suppression of glioma cell proliferation upon inhibition of the IRE1 enzyme function

Silencing of NAMPT leads to up-regulation of insulin receptor substrate 1 gene expression in U87 glioma cells

Objective. The aim of the present study was to investigate the effect of adipokine NAMPT (nicotinamide phosphoribosyltransferase) silencing on the expression of genes encoding IRS1 (insulin receptor substrate 1) and some other proliferation related proteins in U87 glioma cells for evaluation of the possible significance of this adipokine in intergenic interactions

Hypoxic regulation of the expression of anti-angiogenic genes in U87 glioma cells with loss of function of ern1 signaling enzyme

The angiogenesis is an important component of tumor growth and tightly associated with hypoxia. The expression level of genes related to regulation of angiogenesis (BAI2, SPARC, TIMP1, TIMP2, TIMP3, TIMP4, THBS1, THBS2, ADAMTS5 and FGF2) in glioma U87cells and cells with suppressed function of signaling enzyme ERN1, a major mediator of the endoplasmic reticulum stress by qPCR, was studied. We have shown that the expression of genes encoding BAI2, SPARC, TIMP2, TIMP3, THBS1 and THBS2 is strongly increased in glioma cells with ERN1 signaling enzyme loss of function, being more intense for TIMP2, TIMP3 and THBS1 genes. At the same time, the expression of genes encoding TIMP1, TIMP4, ADAMTS5 and FGF2 is significantly decreased with more strong effect for ADAMTS5 and TIMP4 genes. At hypoxia, the expression of most of studied genes in both glioma cell types is affected. Hypoxia induced the expression of TIMP1, TIMP3 and ADAMTS5 genes both in control glioma cells and cells with ERN1 enzyme loss of function. However, the effect of hypoxia towards TIMP2 gene expression was observed only in control glioma cells. At the same time, the expression of genes encoding BAI2, SPARC, THBS1, THBS2, ADAMTS5 and FGF2 is decreased under hypoxia action, but its expression mostly depended on ERN1 signaling enzyme function. The results of this study provide strong evidence that suppression of ERN1 signaling enzyme function, as well as hypoxia, changes the expression of genes related to regulation of angiogenesis in glioma cells. It is possible that changes in the expression of these genes contribute to the suppression of glioma cells’ proliferation by blockade of ERN1 signaling enzyme functioning

Hypoxia controls the expression of genes responsible for serine synthesis in U87MG cells on ERN1-dependent manner

Objective. Serine synthesis as well as endoplasmic reticulum stress and hypoxia are important factors of malignant tumor growth including glioblastoma. Previous studies have shown that the knockdown of ERN1 (endoplasmic reticulum to nucleus signaling) significantly suppressed the glioblastoma cell proliferation and modified the hypoxia regulation. The present study is aimed to investigate the impact of hypoxia on the expression of PHGDH (phosphoglycerate dehydrogenase), PSAT1 (phosphoserine aminotransferase 1), PSPH (phosphoserine phosphatase), ATF4 (activating transcription factor 4), and SHMT1 (serine hydroxymethyltransferase 1) in U87MG glioblastoma cells in relation to knockdown of ERN1 with the intent to reveal the role of ERN1 signaling pathway on the endoplasmic reticulum stress-dependent regulation of expression of these genes

Expression of DNAJB9 and some other genes is more sensitive to SWCNTs in normal human astrocytes than glioblastoma cells

Objective. Single-walled carbon nanotubes (SWCNTs) are considered to be one of the nanomaterials attractive for biomedical applications, particularly in the health sciences as imaging probes and drug carriers, especially in the field of cancer therapy. The increasing exploitation of nanotubes necessitates a comprehensive evaluation of the potential impact of these nanomaterials, which purposefully accumulate in the cell nucleus, on the human health and the function of the genome in the normal and tumor tissues. The aim of this study was to investigate the sensitivity of the expression of DNAJB9 and some other genes associated with the endoplasmic reticulum (ER) stress and cell proliferation to low doses of SWCNTs in normal human astrocytes (NHA/TS) and glioblastoma cells (U87MG) with and without an inhibition of ERN1 signaling pathway of the ER stress

Expression of IDE and PITRM1 genes in ERN1 knockdown U87 glioma cells: effect of hypoxia and glucose deprivation

Objective. The aim of the present investigation was to study the expression of genes encoding polyfunctional proteins insulinase (insulin degrading enzyme, IDE) and pitrilysin metallopeptidase 1 (PITRM1) in U87 glioma cells in response to inhibition of endoplasmic reticulum stress signaling mediated by ERN1/IRE1 (endoplasmic reticulum to nucleus signaling 1) for evaluation of their possible significance in the control of metabolism through ERN1 signaling as well as hypoxia, glucose and glutamine deprivations