ER stress and distinct outputs of the IRE1α RNase control proliferation and senescence in response to oncogenic Ras

Nicholas Blazanin, Jeongin Son, Alayna B. Craig-Lucas, Christian L. John, Kyle J. Breech, Michael A. Podolsky, Adam B. Glick

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Oncogenic Ras causes proliferation followed by premature senescence in primary cells, an initial barrier to tumor development. The role of endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) in regulating these two cellular outcomes is poorly understood. During ER stress, the inositol requiring enzyme 1α (IRE1α) endoribonuclease (RNase), a key mediator of the UPR, cleaves Xbp1 mRNA to generate a potent transcription factor adaptive toward ER stress. However, IRE1α also promotes cleavage and degradation of ER-localized mRNAs essential for cell death. Here, we show that oncogenic HRas induces ER stress and activation of IRE1α. Reduction of ER stress or Xbp1 splicing using pharmacological, genetic, and RNAi approaches demonstrates that this adaptive response is critical for HRas-induced proliferation. Paradoxically, reduced ER stress or Xbp1 splicing promotes growth arrest and premature senescence through hyperactivation of the IRE1α RNase. Microarray analysis of IRE1α- and XBP1-depleted cells, validation using RNA cleavage assays, and 5′ RACE identified the prooncogenic basic helix–loop–helix transcription factor ID1 as an IRE1α RNase target. Further, we demonstrate that Id1 degradation by IRE1α is essential for HRas-induced premature senescence. Together, our studies point to IRE1α as an important node for posttranscriptional regulation of the early Ras phenotype that is dependent on both oncogenic signaling as well as stress signals imparted by the tumor microenvironment and could be an important mechanism driving escape from Ras-induced senescence.

Original languageEnglish (US)
Pages (from-to)9900-9905
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume114
Issue number37
DOIs
StatePublished - Sep 12 2017

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Endoplasmic Reticulum Stress
Inositol
Ribonucleases
Enzymes
Unfolded Protein Response
Transcription Factors
Endoribonucleases
RNA Cleavage
Messenger RNA
Tumor Microenvironment
Microarray Analysis
Heat-Shock Proteins
RNA Interference
Endoplasmic Reticulum
Cell Death
Pharmacology
Phenotype
Growth

All Science Journal Classification (ASJC) codes

  • General

Cite this

Blazanin, Nicholas ; Son, Jeongin ; Craig-Lucas, Alayna B. ; John, Christian L. ; Breech, Kyle J. ; Podolsky, Michael A. ; Glick, Adam B. / ER stress and distinct outputs of the IRE1α RNase control proliferation and senescence in response to oncogenic Ras. In: Proceedings of the National Academy of Sciences of the United States of America. 2017 ; Vol. 114, No. 37. pp. 9900-9905.
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abstract = "Oncogenic Ras causes proliferation followed by premature senescence in primary cells, an initial barrier to tumor development. The role of endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) in regulating these two cellular outcomes is poorly understood. During ER stress, the inositol requiring enzyme 1α (IRE1α) endoribonuclease (RNase), a key mediator of the UPR, cleaves Xbp1 mRNA to generate a potent transcription factor adaptive toward ER stress. However, IRE1α also promotes cleavage and degradation of ER-localized mRNAs essential for cell death. Here, we show that oncogenic HRas induces ER stress and activation of IRE1α. Reduction of ER stress or Xbp1 splicing using pharmacological, genetic, and RNAi approaches demonstrates that this adaptive response is critical for HRas-induced proliferation. Paradoxically, reduced ER stress or Xbp1 splicing promotes growth arrest and premature senescence through hyperactivation of the IRE1α RNase. Microarray analysis of IRE1α- and XBP1-depleted cells, validation using RNA cleavage assays, and 5′ RACE identified the prooncogenic basic helix–loop–helix transcription factor ID1 as an IRE1α RNase target. Further, we demonstrate that Id1 degradation by IRE1α is essential for HRas-induced premature senescence. Together, our studies point to IRE1α as an important node for posttranscriptional regulation of the early Ras phenotype that is dependent on both oncogenic signaling as well as stress signals imparted by the tumor microenvironment and could be an important mechanism driving escape from Ras-induced senescence.",
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ER stress and distinct outputs of the IRE1α RNase control proliferation and senescence in response to oncogenic Ras. / Blazanin, Nicholas; Son, Jeongin; Craig-Lucas, Alayna B.; John, Christian L.; Breech, Kyle J.; Podolsky, Michael A.; Glick, Adam B.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 114, No. 37, 12.09.2017, p. 9900-9905.

Research output: Contribution to journalArticle

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T1 - ER stress and distinct outputs of the IRE1α RNase control proliferation and senescence in response to oncogenic Ras

AU - Blazanin, Nicholas

AU - Son, Jeongin

AU - Craig-Lucas, Alayna B.

AU - John, Christian L.

AU - Breech, Kyle J.

AU - Podolsky, Michael A.

AU - Glick, Adam B.

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AB - Oncogenic Ras causes proliferation followed by premature senescence in primary cells, an initial barrier to tumor development. The role of endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) in regulating these two cellular outcomes is poorly understood. During ER stress, the inositol requiring enzyme 1α (IRE1α) endoribonuclease (RNase), a key mediator of the UPR, cleaves Xbp1 mRNA to generate a potent transcription factor adaptive toward ER stress. However, IRE1α also promotes cleavage and degradation of ER-localized mRNAs essential for cell death. Here, we show that oncogenic HRas induces ER stress and activation of IRE1α. Reduction of ER stress or Xbp1 splicing using pharmacological, genetic, and RNAi approaches demonstrates that this adaptive response is critical for HRas-induced proliferation. Paradoxically, reduced ER stress or Xbp1 splicing promotes growth arrest and premature senescence through hyperactivation of the IRE1α RNase. Microarray analysis of IRE1α- and XBP1-depleted cells, validation using RNA cleavage assays, and 5′ RACE identified the prooncogenic basic helix–loop–helix transcription factor ID1 as an IRE1α RNase target. Further, we demonstrate that Id1 degradation by IRE1α is essential for HRas-induced premature senescence. Together, our studies point to IRE1α as an important node for posttranscriptional regulation of the early Ras phenotype that is dependent on both oncogenic signaling as well as stress signals imparted by the tumor microenvironment and could be an important mechanism driving escape from Ras-induced senescence.

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