Tag Archives: endoplasmic reticulum stress
Biochemical mechanism of the o,p’-DDD effect on the adrenal cortex
A. S. Mikosha, O. I. Kovzun
V. P. Komisarenko Institute of Endocrinology and Metabolism, National Academy of Medical Sciences of Ukraine, Kyiv;
e-mail: asmikosha@gmail.com
o,p’-Dichlorodiphenyldichloroethane (o,p’-DDD, mitotane) is used in the treatment of adrenocortical cancer and Cushing’s disease. This medicine induces numerous biochemical changes in the adrenal cortex, as well as disorder in the mitochondrial structure. Therewith, the level of produced corticosteroid hormones is significantly reduced. One of the possible causes can be a decrease in the NADPH level due to inhibition of the activity of its reduction system and increased NADPH consumption during the glutathione reduction catalyzed by glutathione reductase. o,p’-DDD is partially metabolized in the adrenal glands, and the main metabolite (in terms of quantity) is o,p’-dichlorodiphenylacetic acid. However, attempts to find a physiologically active component among metabolites were unsuccessful. The most pronounced changes caused by o,p’-DDD were found in the mitochondria of the adrenal cortex. The respiration at the level of IV and I complexes is suppressed, the protein content of these complexes decreases. The phospholipid composition of the tissue altered and the concentration of diphosphatidylglycerol, the most important component of mitochondrial membranes, decreased. In our opinion, o,p’-DDD, owing to its high lipophilicity, accumulates in the mitochondria membranes and causes conformational disorder followed by disorder in mitochondrial functions. It was shown that o,p’-DDD acts as an inhibitor of acyl-CoA-cholesterol acyltransferase (ACAT, SOAT1). Therefore, adenocorticocytes accumulate free cholesterol, causing endoplasmic reticulum stress, mitochondrial swelling and caspases activation. Increased apoptosis leads to a decline in adrenal function and to a decrease in weight of adrenal glands.
Scientific and practical activity of the Department of Molecular Biology of the Palladin Institute of Biochemistry of NAS of Ukraine
R. P. Vynogradova, M. V. Grigorieva, V. M. Danilova
Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: valdan@biochem.kiev.ua
The present paper gives a detailed analysis of scientific and practical activity of the Department of Molecular Biology of the Palladin Institute of Biochemistry of NAS of Ukraine in the context of the history of its development. The most important results of the research of molecular mechanisms of regulation of glycolysis and gene expression in malignant tumors upon hypoxia; identification of key transcription factors of the regulation of proliferation and the role of alternative splicing in the regulation of the activity of the different PFKFB isoforms are reported. In recent years, the efforts of the department’s staff have been focused on studying the role of endoplasmic reticulum stress and the regulation of metabolism and proliferation processes at the level of gene expression in genome reprogramming. The obtained results allow to establish the molecular bases of pathogenesis of various diseases and to develop new effective methods for their diagnosis, prevention and treatment.
Hypoxic regulation of the expression of cell proliferation related genes in U87 glioma cells upon inhibition of IRE1 signaling enzyme
O. H. Minchenko1, D. O. Tsymbal1, D. O. Minchenko1,2,
O. O. Riabovol1, O. O. Ratushna1, L. L. Karbovskyi1
1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: ominchenko@yahoo.com;
2Bohomolets National Medical University, Kyiv, Ukraine
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.
Effect of hypoxia on the expression of genes that encode some IGFBP and CCN proteins in U87 glioma cells depends on IRE1 signaling
O. H. Minchenko1, A. P. Kharkova1, D. O. Minchenko1,2, L. L. Karbovskyi1
1Palladin Institute of Biochemistry, National Academy
of Sciences of Ukraine, Kyiv;
e-mail: ominchenko@yahoo.com;
2Bohomolets National Medical University, Kyiv, Ukraine
We have studied hypoxic regulation of the expression of different insulin-like growth factor binding protein genes in U87 glioma cells in relation to inhibition of IRE1 (inositol requiring enzyme-1), a central mediator of endoplasmic reticulum stress, which controls cell proliferation and tumor growth. We have demonstrated that hypoxia leads to up-regulation of the expression of IGFBP6, IGFBP7, IGFBP10/CYR61, WISP1, and WISP2 genes and down-regulation – of IGFBP9/NOV gene at the mRNA level in control glioma cells, being more significant changes for IGFBP10/CYR61 and WISP2 genes. At the same time, inhibition of IRE1 modifies the effect of hypoxia on the expression of all studied genes: eliminates sensitivity to hypoxia the expression of IGFBP7 and IGFBP9/NOV genes, suppresses effect of hypoxia on IGFBP6, IGFBP10/CYR61, and WISP2 genes, and slightly enhances hypoxic regulation of WISP1 gene expression in glioma cells. We have also demonstrated that the expression of all studied genes in glioma cells is regulated by IRE1 signaling enzyme upon normoxic condition, because inhibition of IRE1 significantly up-regulates IGFBP7, IGFBP10/CYR61, WISP1, and WISP2 genes and down-regulates IGFBP6 and IGFBP9/NOV genes as compared to control glioma cells. The present study demonstrates that hypoxia, which contributes to tumor growth, affects all studied IGFBP and WISP gene expressions and that inhibition of IRE1 preferentially abolishes or suppresses the hypoxic regulation of these gene expressions and thus possibly contributes to slower glioma growth. Moreover, inhibition of IRE1, which correlates with suppression of cell proliferation and glioma growth, is down-regulated expression of pro-proliferative IGFBP genes, attesting to the fact that endoplasmic reticulum stress is a necessary component of malignant tumor growth.
Inhibition of IRE1 modifies effect of glucose deprivation on the expression of TNFα-related genes in U87 glioma cells
I. V. Kryvdiuk1, D. O. Minchenko1,2, N. A. Hlushchak1,
O. O. Ratushna1, L. L. Karbovskyi1, O. H. Minchenko1
1Palladin Institute of Biochemistry National Academy of Sciences of Ukraine, Kyiv;
e-mail: ominchenko@yahoo.com;
2Bohomolets National Medical University, Kyiv, Ukraine
Inhibition of IRE1 (inositol requiring enzyme-1), the major signaling pathway of endoplasmic reticulum 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 overexpressing 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.
Endoplasmic reticulum stress, its sensor and signalling systems and the role in regulation of gene expression at malignant tumor growth and hypoxia
O. H. Minchenko, A. P. Kharkova, T. V. Bakalets, I. V. Kryvdiuk
Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: ominchenko@yahoo.com
Hypoxia is one of the inductors of the expression of a large group of genes, which control glycolysis and proliferation processes in low oxygen conditions or as a result of low oxygen consumption. Moreover, hypoxia is one of the factors which induce the endoplasmic reticulum stress which, like hypoxia, is an obligatory component of malignant tumor growth and is connected with cytoplasm and nuclei through three sensor and signalling systems: PERK, ATF6 та ERN1. The suppression of ERN1, the main sensing and signalling enzyme of endoplasmic reticulum stress, leads to a decrease of tumor growth and changes the character of hypoxic regulation of many genes responsible for the control of proliferation and glycolysis. ERN1 sensing and signalling system controls the expression of a large set of genes, which are dependent on endoplasmic reticulum stress as well as hypoxia. Moreover, this signalling pathway is an important factor of malignant tumor growth.
Inhibition of ERN1 signaling enzyme affects hypoxic regulation of the expression of E2F8, EPAS1, HOXC6, ATF3, TBX3 and FOXF1 genes in U87 glioma cells
O. H. Minchenko1, D. O. Tsymbal1, D. O. Minchenko1,2,
O. V. Kovalevska1, L. L. Karbovskyi1, A. Bikfalvi3
1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: ominchenko@yahoo.com;
2Bogomolets National Medical University, Kyiv, Ukraine;
3INSERM U1029 Angiogenesis and Cancer Microenvironment Laboratory,
University Bordeaux 1, Talence, France
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 F1), 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 ERN1 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.