Inhibition of ERN1 modifies the hypoxic regulation of the expression of TP53-related genes in U87 glioma cells

AbstractInhibition of ERN1 (endoplasmic reticulum to nuclei 1), the major signalling pathway of endoplasmic reticulum stress, significantly decreases tumor growth. We have studied the expression of tumor protein 53 (TP53)- related genes such as TOPORS (topoisomerase I binding, arginine/serine-rich, E3 ubiquitin protein ligase), TP53BP1 (TP53 binding protein 1), TP53BP2, SESN1 (sestrin 1), NME6 (non-metastatic cells 6), and ZMAT3 (zinc finger, Matrin-type 3) in glioma cells expressing dominantnegative ERN1 under baseline and hypoxic conditions. We demonstrated that inhibition of ERN1 function in U87 glioma cells resulted in increased expression of RYBP, TP53BP2, and SESN1 genes, but decreased expression of TP53BP1, TOPORS, NME6, and ZMAT3 genes. Moreover, inhibition of ERN1 affected hypoxia-mediated changes in expression of TP53-related genes and their magnitude. Indeed, hypoxia has no effect on expression of TP53BP1 and SESN1 in control cells, while resulted in increased expression of these genes in cells with inhibited ERN1 function. Magnitude of hypoxia-mediated changes in expression levels of RYBP and TP53BP2 was gene specific and more robust in the case of TP53BP2. Hypoxiamediated decrease in expression levels of TOPORS was more prominent if ERN1 was inhibited. Present study demonstrates that fine-tuning of the expression of TP53- associated genes depends upon endoplasmic reticulum stress signaling under normal and hypoxic conditions. Inhibition of ERN1 branch of endoplasmic reticulum stress response correlates with deregulation of p53 signaling and slower tumor growth.

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Inhibition of kinase and endoribonuclease activity of ERN1/IRE1α affects expression of proliferationrelated genes in U87 glioma cells

Endoplasmic Reticulum Stress in Diseases ◽

10.1515/ersc-2015-0002 ◽

2015 ◽

Vol 2 (1) ◽

Cited By ~ 10

Author(s):

Oleksandr H. Minchenko ◽

Dariia O. Tsymbal ◽

Dmytro O. Minchenko ◽

Michel Moenner ◽

Olena V. Kovalevska ◽

...

Keyword(s):

Endoplasmic Reticulum ◽

Transcription Factor ◽

Endoplasmic Reticulum Stress ◽

Tumor Growth ◽

Mrna Level ◽

Glioma Cells ◽

Dominant Negative ◽

Fine Tuning ◽

Gene Expressions ◽

Endoribonuclease Activity

AbstractInhibition of ERN1/IRE1α (endoplasmic reticulum to nucleus signaling 1/inositol requiring enzyme-1α), the major signaling pathway of endoplasmic reticulum stress, significantly decreases tumor growth. We have studied the expression of 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 overexpressing dominant-negative ERN1/IRE1α defective in endoribonuclease (dnr-ERN1) as well as defective in both kinase and endonuclease (dn-ERN1) activity of ERN1/IRE1α. We have demonstrated that the expression of all studied genes is decreased at the mRNA level in cells with modified ERN1/IRE1α; TBX3, however, is increased in these cells as compared to control glioma cells. Changes in protein levels of E2F8, HOXC6, ATF3, and TBX3 corresponded to changes in mRNAs levels. We also found that two mutated ERN1/IRE1α have differential effects on the expression of studied transcripts. The presence of kinase and endonuclease deficient ERN1/IRE1α in glioma cells had a less profound effect on the expression of E2F8, HOXC6, and TBX3 genes than the blockade of the endoribonuclease activity of ERN1/IRE1α alone. Kinase and endonuclease deficient ERN1/IRE1α suppresses ATF3 and FOXF1 gene expressions, while inhibition of only endoribonuclease of ERN1/IRE1α leads to the up-regulation of these gene transcripts. The present study demonstrates that fine-tuning of the expression of proliferation related genes is regulated by ERN1/IRE1α an effector of endoplasmic reticulum stress. Inhibition of ERN1/IRE1α, especially its endoribonuclease activity, correlates with deregulation of proliferation related genes and thus slower tumor growth.

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Inhibition of IRE1 signaling affects expression of a subset genes encoding for TNF-related factors and receptors and modifies their hypoxic regulation in U87 glioma cells

Endoplasmic Reticulum Stress in Diseases ◽

10.1515/ersc-2016-0001 ◽

2016 ◽

Vol 3 (1) ◽

Cited By ~ 2

Author(s):

Oleksandr H. Minchenko ◽

Iryna V. Kryvdiuk ◽

Dmytro O. Minchenko ◽

Olena O. Riabovol ◽

Oleh V. Halkin

Keyword(s):

Endoplasmic Reticulum ◽

Cell Death ◽

Endoplasmic Reticulum Stress ◽

Tumor Growth ◽

Glioma Cells ◽

Dominant Negative ◽

Gene Expressions ◽

Related Factors ◽

Genes Encoding ◽

Glioma Growth

AbstractInhibition of IRE1 (inositol requiring enzyme-1), the major signaling pathway of endoplasmic reticulum stress, significantly decreases tumor growth and proliferation of glioma cells. To elucidate the role of IRE1- mediated glioma growth, we studied the expression of a subset genes encoding for TNF (tumor necrosis factor)- related factors and receptors and their hypoxic regulation in U87 glioma cells overexpressing dominant-negative IRE1 (dnIRE1). We demonstrated that the expression of TNFAIP1, TNFRSF10D, TNFRSF21, TNFRSF11B, TNFSF7, and LITAF genes is increased in glioma cells with modified IRE1; however, TNFRSF10B, TRADD, and TNFAIP3 is down-regulated in these cells as compared to their control counterparts. We did not find TNFRSF1A gene expression to change significantly under this experimental condition. In control glioma cells, hypoxia leads to the up-regulated expression of TNFAIP1, TNFAIP3, TRADD, and TNFRSF10D genes and the concomitant down-regulation of TNFRSF21, TNFRSF11B, and LITAF genes; while, TNFRSF10B and TNFRSF1A genes are resistant to hypoxic treatment. However, inhibition of IRE1 modifies the hypoxic regulation of LITAF, TNFRSF21, TNFRSF11B, and TRADD genes and introduces hypoxia-induced sensitivity to TNFRSF10B, TNFRSF1A, and TNFSF7 gene expressions. Furthermore, knockdown by siRNA of TNFRSF21 mRNA modifies the hypoxic effect on the IRE1-dependent rate of proliferation and cell death in U87 glioma cells. The present study demonstrates that fine-tuned manipulation of the expression of TNF-related factors and receptors directly relating to cell death and proliferation, is mediated by an effector of endoplasmic reticulum stress, IRE1, as well as by hypoxia in a gene-specific manner. Thus, inhibition of the kinase and endoribonuclease activities of IRE1 correlates with deregulation of TNF-related factors and receptors in a manner that is gene specific and thus slows tumor growth.

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The fine-tuning of endoplasmic reticulum stress response and autophagy activation during trophoblast syncytialization

Cell Death and Disease ◽

10.1038/s41419-019-1905-6 ◽

2019 ◽

Vol 10 (9) ◽

Cited By ~ 1

Author(s):

Daniel Bastida-Ruiz ◽

Lucile Yart ◽

Christine Wuillemin ◽

Pascale Ribaux ◽

Nolwenn Morris ◽

...

Keyword(s):

Endoplasmic Reticulum ◽

Endoplasmic Reticulum Stress ◽

Cell Survival ◽

Time Course ◽

Fine Tuning ◽

Endoplasmic Reticulum Stress Response ◽

Trophoblastic Cell ◽

Biochemical Alterations ◽

Existing Structures ◽

Promote Cell Survival

Abstract The syncytiotrophoblast (STB) is a multinuclear layer forming the outer surface of the fetal part of the placenta deriving from villous cytotrophoblastic cell (vCTB) fusion and differentiation. This syncytialization process is characterized by morphological and biochemical alterations of the trophoblast, which probably require removal of pre-existing structures and proteins to maintain cell homeostasis and survival. Interestingly, autophagy, which allows degradation and recycling of cellular components, was shown to be activated in syncytiotrophoblast. Here we examined the involvement of endoplasmic reticulum stress (ERS) response in autophagy activation during vCTB syncytialization. We first demonstrated the activation of ERS response and autophagy during the time course of trophoblastic cell fusion and differentiation. Alteration of autophagy activation in vCTB by chemical treatments or Beclin-1 expression modulation leads to a decrease in trophoblastic syncytialization. Furthermore, ERS response inhibition by chemical treatment or siRNA strategy leads to a default in syncytialization, associated with alteration of autophagy markers and cell survival. From these data, we suggest that ERS response, by fine regulation of autophagy activation, may serve as an adaptive mechanism to promote cell survival during trophoblastic syncytialization.

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