Tag Archives: hypoxia
HSPA5 and DNAJB9 genes expression in glioblastoma cells and normal astrocytes under hypoxia and endoplasmic reticulum stress
O. V. Halkin*, Y. M. Viletska, M. Y. Sliusar, S. V. Danilovskyi,
Y. V. Kulish, O. V. Rudnytska, O. H. Minchenko
Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
*e-mail: oleggal2014@gmail.com
Received: 07 October 2025; Revised: 10 December 2025;
Accepted: 30 January 2026; Available on-line: 23 February 2026
Hypoxia and ER stress are obligate factors in tumor growth, however, the interaction between these factors has not been sufficiently studied. Heat shock proteins HSPA5 and DNAJB9 as a key components of the endoplasmic reticulum stress response play an important role in the growth of malignant tumors, including glioblastomas. This study aimed to investigate the interaction between hypoxia and ER stress in controlling HSPA5 and DNAJB9 expression in glioblastoma cells and normal astrocytes. Hypoxia was created with dimethyloxalylglycine, ER stress was induced with tunicamycin and thapsigargin, HSPA5 and DNAJB9 expression was studied by qPCR. It has been established that in astrocytes HSPA5 and DNAJB9 expression was resistant to hypoxia. However, in glioblastoma cells, the expression of these genes under hypoxia was increased. Tunicamycin and thapsigargin enhanced HSPA5 and DNAJB9 expression with a much stronger effect in glioblastoma cells. When these ER stress inducers were combined with hypoxia their effect was modified to a greater extent in normal astrocytes. The obtained results indicate different cell-specific sensitivity of HSPA5 and DNAJB9 expression to hypoxia and ER stress inducers.
Scientific achievements of the Department of Molecular Biology in understanding stress-dependent mechanisms of glioma growth
O. H. Minchenko*, Y. M. Viletska, M. Y. Sliusar, O. O. Khita
Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine,
Department of Molecular Biology, Kyiv;
*e-mail: ominchenko@yahoo.com
Received: 09 July 2025; Revised: 25 July 2025;
Accepted: 30 October 2025; Available on-line: 02 December 2025
Since 2005, the Department of Molecular Biology has initiated research aimed at solving key problems in biochemistry and molecular biology, with an emphasis on elucidating the molecular basis of malignant tumor growth and the mechanisms of hypoxic regulation, the role of alternative splicing in the mechanisms of gene expression regulation, as well as the fundamental importance of endoplasmic reticulum stress in maintaining homeostasis and the development of pathological conditions, in particular, the growth of glioblastomas, the most malignant brain tumors that are difficult to treat. It has been shown that the expression of different 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFKFB), key glycolysis regulators, is exacerbated in various malignant tumors and that PFKFB4 is a marker of tumor growth. It has been established that the expression level of PFKFB4 is controlled under hypoxia by a HIF-dependent mechanism, and a HIF-specific sequence has been identified in the promoter, the mutation of which completely removes hypoxic regulation of the PFKFB4 gene. Numerous splice variants of different PFKFB and VEGFA genes have also been identified. It has been established that inhibition of endoplasmic reticulum stress, its ERN1 signaling pathway, reduces the proliferation of glioblastoma cells by changing the expression levels of oncogenes, tumor suppressors, mitochondrial enzymes, as well as insulin and glucocorticoid receptors and their dependent proteins. An important role of ERN1 protein kinase activity in regulating the expression of various genes has been revealed, and its inhibition has been shown to lead to increased invasiveness of glioblastoma cells upon ERN1 knockdown. Attention is focused on studying non-canonical mechanisms of hypoxic gene expression regulation and its dependence on endoplasmic reticulum stress.
Expression of tumor growth related genes in IRE1 knockdown U87 glioma cells: effect of hypoxia
O. H. Minchenko1, O. Y. Luzina1, O. S. Hnatiuk1,
D. O. Minchenko1,2, I. A. Garmash1, O. O. Ratushna1
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 IRE1 signaling enzyme knockdown as well as hypoxia on the expression of genes encoding the important tumor growth related proteins (BRCA1, DEK, BCL2L1, COL6A1, TPD52, HOMER3, and GNPDA1) in U87 glioma cells. It was shown that the expression level of breast cancer 1 early onset (BRCA1) and tumor protein D52 (TPD52) mRNAs are strongly up-regulated in U87 glioma cells by down-regulation of IRE1 expression in comparison with the control cells. At the same time the expression level of collagen, type VI, alpha 1 (COL6A1), DEK oncogene (DEK), glucosamine-6-phosphate deaminase 1 (GNPDA1) and homer homolog 3 (HOMER3) was significantly down-regulated in glioma cells under these experimental conditions. It was also shown that hypoxia up-regulated the expression level of COL6A1 and TPD52 mRNAs and down-regulated – BRCA1, DEK, and GNPDA1 mRNAs in control glioma cells and that down-regulation of IRE1, which control cell proliferation and tumor growth, modified the effect of hypoxia on the expression of COL6A1, DEK, BCL2L1, HOMER3, and GNPDA1 genes. The present study demonstrated that hypoxia affected the expression of most studied genes in IRE1-dependent manner.
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.
IRE1 knockdown modifies hypoxic regulation of cathepsins and LONP1 genes expression in U87 glioma cells
O. H. Minchenko1, О. O. Riabovol1, O. V. Halkin1,
D. O. Minchenko1,2, О. O. Ratushna1
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 hypoxia on the expression of genes encoding for LONP1/PRSS15 and cathepsins in U87 glioma cells in relation to inhibition of inositol requiring enzyme-1 (IRE1). It was shown that hypoxia up-regulated the expression of CTSA, CTSB, CTSD, CTSF, CTSK, and LONP1 genes and down-regulated the expression of CTSC, CTSL, CTSO, and CTSS genes in control glioma cells (transfected by empty vector). Inhibition of ІRE1 signaling enzyme function in these glioma cells modified effect of hypoxia on the expression of most studied genes: eliminated the effect of hypoxia on CTSA, and LONP1 genes, introduced reverse changes on CTSD and CTSS genes, reduced – on CTSF and CTSK genes, and enhanced – on CTSB and CTSL genes. Therefore, hypoxia affected the expression level of most studied genes in relation to the functional activity of IRE1 enzyme, a central mediator of endoplasmic reticulum stress, which control cell proliferation and tumor growth.
Inhibition of IRE1 modifies hypoxic regulation of G6PD, GPI, TKT, TALDO1, PGLS and RPIA genes expression in U87 glioma cells
O. H. Minchenko1, I. A. Garmash1, D. O. Minchenko1,2,
A. Y. Kuznetsova1, O. O. Ratushna1
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 hypoxia on the expression level of mRNA of the basic enzymes of pentose-phosphate cycle (G6PD, TKT, TALDO1, PGLS and RPIA) and glucose-6-phosphate isomerase (GPI) in U87 glioma cells in relation to inhibition of IRE1 (inositol requiring enzyme 1). It was shown that hypoxia leads to up-regulation of the expression of GPI and PGLS genes and to down-regulation of TALDO1 and RPIA genes in control glioma cells. Changes for GPI gene were more significant than for other genes. At the same time, inhibition of IRE1 modified the effect of hypoxia on the expression of all studied genes. In particular, it increased sensitivity to hypoxia of G6PD and TKT genes expression and suppressed the effect of hypoxia on the expression of GPI and RPIA genes. Additionally, inhibition of IRE1 eliminated hypoxic regulation of PGLS gene and did not change significantly effect of hypoxia on the expression of TALDO1 gene in glioma cells. Present study demonstrated that hypoxia, which often contributes to tumor growth, affects the expression of most studied genes and inhibition of IRE1 modified the hypoxic regulation of pentose-phosphate cycle gene expressions in a gene specific manner and thus possibly contributes to slower glioma growth, but several aspects of this regulation warrant further investigation.
Hypoxic regulation of MYBL1, MEST, TCF3, TCF8, GTF2B, GTF2F2 and SNAI2 genes expression in U87 glioma cells upon IRE1 inhibition
O. H. Minchenko1, D. O. Tsymbal1, D. O. Minchenko1,2, O. O. Kubaychuk3
1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: ominchenko@yahoo.com;
2Bohomolets National Medical University, Kyiv, Ukraine;
3National University of Food Technologies, Kyiv, Ukraine
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.
Fatty acids composition of inner mitochondrial membrane of rat cardiomyocytes and hepatocytes during hypoxia-hypercapnia
S. V. Khyzhnyak, S. V. Midyk, S. V. Sysoliatin, V. М. Voitsitsky
National University of Life and Environmental Sciences of Ukraine, Kyiv;
е-mail: khs2014@ukr.net
We studied the influence of hypoxic-hypercapnic environment under the effect of hypothermia (artificial hibernation) on fatty acids spectrum of inner mitochondrial membrane (IMM) lipids of rat cardiomyocytes and hepatocytes. Specific for cellular organelles redistribution of IMM fatty acids was determined. It led to the reduction of total amount of saturated fatty acids (SFAs) and increase of unsaturated fatty acids (UFAs) in cardiomyocytes and to the increase of SFAs and decrease of UFAs in hepatocytes. The decrease in the content of oleic acid and increased content of arachidonic and docosahexaenoic acids in IMM were shown. This may be due to their role in the regulatory systems during hibernation, as well as following exit therefrom. It is assumed that artificial hibernation state is characterized by the stress reaction leading to optimal readjustment of fatty acids composition of membrane lipids, which supports functional activity of mitochondria in hepatocytes and cardiomyocytes.
Effect of hypoxia on the expression of nuclear genes encoding mitochondrial proteins in U87 glioma cells
O. H. Minchenko1, О. O. Riabovol1, D. O. Tsymbal1, D. O. Minchenko1,2, О. O. Ratushna1
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 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 ІRE1 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 ІRE1 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.