1
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Wang SF, Chang YL, Liu TY, Huang KH, Fang WL, Li AFY, Yeh TS, Hung GY, Lee HC. Mitochondrial dysfunction decreases cisplatin sensitivity in gastric cancer cells through upregulation of integrated stress response and mitokine GDF15. FEBS J 2024; 291:1131-1150. [PMID: 37935441 DOI: 10.1111/febs.16992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 09/18/2023] [Accepted: 11/03/2023] [Indexed: 11/09/2023]
Abstract
Gastric neoplasm is a high-mortality cancer worldwide. Chemoresistance is the obstacle against gastric cancer treatment. Mitochondrial dysfunction has been observed to promote malignant progression. However, the underlying mechanism is still unclear. The mitokine growth differentiation factor 15 (GDF15) is a significant biomarker for mitochondrial disorder and is activated by the integrated stress response (ISR) pathway. The serum level of GDF15 was found to be correlated with the poor prognosis of gastric cancer patients. In this study, we found that high GDF15 protein expression might increase disease recurrence in adjuvant chemotherapy-treated gastric cancer patients. Moreover, treatment with mitochondrial inhibitors, especially oligomycin (a complex V inhibitor) and salubrinal (an ISR activator), respectively, was found to upregulate GDF15 and enhance cisplatin insensitivity of human gastric cancer cells. Mechanistically, it was found that the activating transcription factor 4-C/EBP homologous protein pathway has a crucial function in the heightened manifestation of GDF15. In addition, reactive oxygen species-activated general control nonderepressible 2 mediates the oligomycin-induced ISR, and upregulates GDF15. The GDF15-glial cell-derived neurotrophic factor family receptor a-like-ISR-cystine/glutamate transporter-enhanced glutathione production was found to be involved in cisplatin resistance. These results suggest that mitochondrial dysfunction might enhance cisplatin insensitivity through GDF15 upregulation, and targeting mitokine GDF15-ISR regulation might be a strategy against cisplatin resistance of gastric cancer.
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Affiliation(s)
- Sheng-Fan Wang
- Department of Pharmacy, Taipei Veterans General Hospital, Taiwan
- Department of Clinical Pharmacy, School of Pharmacy, Taipei Medical University, Taiwan
- Department and Institute of Pharmacology, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Institute of Biopharmaceutical Sciences, College of Pharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yuh-Lih Chang
- Department of Pharmacy, Taipei Veterans General Hospital, Taiwan
- Department and Institute of Pharmacology, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Department of Pharmacy, College of Pharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Ting-Yu Liu
- Department and Institute of Pharmacology, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Kuo-Hung Huang
- School of Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Division of General Surgery, Department of Surgery, Taipei Veterans General Hospital, Taiwan
- Department of Surgery, Gastric Cancer Medical Center, Taipei Veterans General Hospital, Taiwan
| | - Wen-Liang Fang
- School of Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Division of General Surgery, Department of Surgery, Taipei Veterans General Hospital, Taiwan
- Department of Surgery, Gastric Cancer Medical Center, Taipei Veterans General Hospital, Taiwan
| | - Anna Fen-Yau Li
- School of Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Department of Anatomical Pathology, Cheng Hsin General Hospital, Taipei, Taiwan
| | - Tien-Shun Yeh
- Institute of Anatomy and Cell Biology, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Giun-Yi Hung
- School of Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Division of Pediatric Hematology and Oncology, Department of Pediatrics, Taipei Veterans General Hospital, Taiwan
| | - Hsin-Chen Lee
- Department and Institute of Pharmacology, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Department of Pharmacy, College of Pharmaceutical Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
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2
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Mijit M, Boner M, Cordova RA, Gampala S, Kpenu E, Klunk AJ, Zhang C, Kelley MR, Staschke KA, Fishel ML. Activation of the integrated stress response (ISR) pathways in response to Ref-1 inhibition in human pancreatic cancer and its tumor microenvironment. Front Med (Lausanne) 2023; 10:1146115. [PMID: 37181357 PMCID: PMC10174294 DOI: 10.3389/fmed.2023.1146115] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 04/12/2023] [Indexed: 05/16/2023] Open
Abstract
Pancreatic cancer or pancreatic ductal adenocarcinoma (PDAC) is characterized by a profound inflammatory tumor microenvironment (TME) with high heterogeneity, metastatic propensity, and extreme hypoxia. The integrated stress response (ISR) pathway features a family of protein kinases that phosphorylate eukaryotic initiation factor 2 (eIF2) and regulate translation in response to diverse stress conditions, including hypoxia. We previously demonstrated that eIF2 signaling pathways were profoundly affected in response to Redox factor-1 (Ref-1) knockdown in human PDAC cells. Ref-1 is a dual function enzyme with activities of DNA repair and redox signaling, responds to cellular stress, and regulates survival pathways. The redox function of Ref-1 directly regulates multiple transcription factors including HIF-1α, STAT3, and NF-κB, which are highly active in the PDAC TME. However, the mechanistic details of the crosstalk between Ref-1 redox signaling and activation of ISR pathways are unclear. Following Ref-1 knockdown, induction of ISR was observed under normoxic conditions, while hypoxic conditions were sufficient to activate ISR irrespective of Ref-1 levels. Inhibition of Ref-1 redox activity increased expression of p-eIF2 and ATF4 transcriptional activity in a concentration-dependent manner in multiple human PDAC cell lines, and the effect on eIF2 phosphorylation was PERK-dependent. Treatment with PERK inhibitor, AMG-44 at high concentrations resulted in activation of the alternative ISR kinase, GCN2 and induced levels of p-eIF2 and ATF4 in both tumor cells and cancer-associated fibroblasts (CAFs). Combination treatment with inhibitors of Ref-1 and PERK enhanced cell killing effects in both human pancreatic cancer lines and CAFs in 3D co-culture, but only at high doses of PERK inhibitors. This effect was completely abrogated when Ref-1 inhibitors were used in combination with GCN2 inhibitor, GCN2iB. We demonstrate that targeting of Ref-1 redox signaling activates the ISR in multiple PDAC lines and that this activation of ISR is critical for inhibition of the growth of co-culture spheroids. Combination effects were only observed in physiologically relevant 3D co-cultures, suggesting that the model system utilized can greatly affect the outcome of these targeted agents. Inhibition of Ref-1 signaling induces cell death through ISR signaling pathways, and combination of Ref-1 redox signaling blockade with ISR activation could be a novel therapeutic strategy for PDAC treatment.
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Affiliation(s)
- Mahmut Mijit
- Department of Pediatrics and Herman B Wells Center for Pediatric Research, Indianapolis, IN, United States
- Indiana University Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Megan Boner
- Department of Pediatrics and Herman B Wells Center for Pediatric Research, Indianapolis, IN, United States
| | - Ricardo A. Cordova
- Indiana University Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianapolis, IN, United States
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Silpa Gampala
- Department of Pediatrics and Herman B Wells Center for Pediatric Research, Indianapolis, IN, United States
- Indiana University Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Eyram Kpenu
- Department of Pediatrics and Herman B Wells Center for Pediatric Research, Indianapolis, IN, United States
| | - Angela J. Klunk
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Chi Zhang
- Indiana University Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianapolis, IN, United States
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, United States
- Department of BioHealth Informatics, Indiana University School of Medicine, Indianapolis, IN, United States
| | - MarK R. Kelley
- Department of Pediatrics and Herman B Wells Center for Pediatric Research, Indianapolis, IN, United States
- Indiana University Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianapolis, IN, United States
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Kirk A. Staschke
- Indiana University Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianapolis, IN, United States
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Melissa L. Fishel
- Department of Pediatrics and Herman B Wells Center for Pediatric Research, Indianapolis, IN, United States
- Indiana University Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianapolis, IN, United States
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, United States
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3
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Leli NM, Koumenis C. A Novel Ubiquitin Complex Regulates Aneuploid Epithelial Tumors by Moderating an Integrated Stress Response. Cancer Discov 2023; 13:535-537. [PMID: 36855916 DOI: 10.1158/2159-8290.cd-22-1440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
SUMMARY Tumor fitness coessentiality gene analysis that aims to expand the repertoire of druggable targets reveals a novel ubiquitin ligase complex, the BICR6 module. Along with the other complex members (UBA6, KCMF1, and UBR4), BIRC6 selectively contributes to the survival of a subset of epithelial tumors with a high degree of aneuploidy by ubiquitinating and suppressing HRI, a component of the integrated stress response adaptive pathway. See related article by Cervia et al., p. 766 (2).
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Affiliation(s)
- Nektaria Maria Leli
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Constantinos Koumenis
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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4
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An mTORC1 to HRI signaling axis promotes cytotoxicity of proteasome inhibitors in multiple myeloma. Cell Death Dis 2022; 13:969. [PMID: 36400754 PMCID: PMC9674573 DOI: 10.1038/s41419-022-05421-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 11/05/2022] [Accepted: 11/08/2022] [Indexed: 11/19/2022]
Abstract
Multiple myeloma (MM) causes approximately 20% of deaths from blood cancers. Notwithstanding significant therapeutic progress, such as with proteasome inhibitors (PIs), MM remains incurable due to the development of resistance. mTORC1 is a key metabolic regulator, which frequently becomes dysregulated in cancer. While mTORC1 inhibitors reduce MM viability and synergize with other therapies in vitro, clinically, mTORC1 inhibitors are not effective for MM. Here we show that the inactivation of mTORC1 is an intrinsic response of MM to PI treatment. Genetically enforced hyperactivation of mTORC1 in MM was sufficient to compromise tumorigenicity in mice. In vitro, mTORC1-hyperactivated MM cells gained sensitivity to PIs and hypoxia. This was accompanied by increased mitochondrial stress and activation of the eIF2α kinase HRI, which initiates the integrated stress response. Deletion of HRI elevated the toxicity of PIs in wt and mTORC1-activated MM. Finally, we identified the drug PMA as a robust inducer of mTORC1 activity, which synergized with PIs in inducing MM cell death. These results help explain the clinical inefficacy of mTORC1 inhibitors in MM. Our data implicate mTORC1 induction and/or HRI inhibition as pharmacological strategies to enhance MM therapy by PIs.
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5
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Shin S, Solorzano J, Liauzun M, Pyronnet S, Bousquet C, Martineau Y. Translational alterations in pancreatic cancer: a central role for the integrated stress response. NAR Cancer 2022; 4:zcac031. [PMID: 36325577 PMCID: PMC9615149 DOI: 10.1093/narcan/zcac031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/27/2022] [Accepted: 09/29/2022] [Indexed: 11/07/2022] Open
Abstract
mRNA translation is a key mechanism for cancer cell proliferation and stress adaptation. Regulation of this machinery implicates upstream pathways such as PI3K/AKT/mTOR, RAS/MEK/ERK and the integrated stress response (ISR), principally coordinating the translation initiation step. During the last decade, dysregulation of the mRNA translation process in pancreatic cancer has been widely reported, and shown to critically impact on cancer initiation, development and survival. This includes translation dysregulation of mRNAs encoding oncogenes and tumor suppressors. Hence, cancer cells survive a stressful microenvironment through a flexible regulation of translation initiation for rapid adaptation. The ISR pathway has an important role in chemoresistance and shows high potential therapeutic interest. Despite the numerous translational alterations reported in pancreatic cancer, their consequences are greatly underestimated. In this review, we summarize the different translation dysregulations described in pancreatic cancer, which make it invulnerable, as well as the latest drug discoveries bringing a glimmer of hope.
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Affiliation(s)
- Sauyeun Shin
- Centre de Recherche en Cancérologie de Toulouse (CRCT), INSERM U1037, Université Toulouse III Paul Sabatier, ERL5294 CNRS, Toulouse, France,Equipe labellisée Ligue Contre le Cancer
| | - Jacobo Solorzano
- Centre de Recherche en Cancérologie de Toulouse (CRCT), INSERM U1037, Université Toulouse III Paul Sabatier, ERL5294 CNRS, Toulouse, France,Equipe labellisée Ligue Contre le Cancer
| | - Mehdi Liauzun
- Centre de Recherche en Cancérologie de Toulouse (CRCT), INSERM U1037, Université Toulouse III Paul Sabatier, ERL5294 CNRS, Toulouse, France,Equipe labellisée Ligue Contre le Cancer
| | - Stéphane Pyronnet
- Centre de Recherche en Cancérologie de Toulouse (CRCT), INSERM U1037, Université Toulouse III Paul Sabatier, ERL5294 CNRS, Toulouse, France,Equipe labellisée Ligue Contre le Cancer
| | - Corinne Bousquet
- Centre de Recherche en Cancérologie de Toulouse (CRCT), INSERM U1037, Université Toulouse III Paul Sabatier, ERL5294 CNRS, Toulouse, France,Equipe labellisée Ligue Contre le Cancer
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6
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Yerlikaya A. Heme-regulated inhibitor: an overlooked eIF2α kinase in cancer investigations. Med Oncol 2022; 39:73. [PMID: 35568791 DOI: 10.1007/s12032-022-01668-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 01/24/2022] [Indexed: 10/18/2022]
Abstract
Heme-regulated inhibitor (HRI) kinase is a serine-threonine kinase, controlling the initiation of protein synthesis via phosphorylating α subunit of eIF2 on serine 51 residue, mainly in response to heme deprivation in erythroid cells. However, recent studies showed that HRI is also activated by several diverse signals, causing dysregulations in intracellular homeostatic mechanisms in non-erythroid cells. For instance, it was reported that the decrease in protein synthesis upon the 26S proteasomal inhibition by MG132 or bortezomib is mediated by increased eIF2α phosphorylation in an HRI-dependent manner in mouse embryonic fibroblast cells. The increase in eIF2α phosphorylation level through the activation of HRI upon 26S proteasomal inhibition is believed to protect cells against the buildup of misfolded and ubiquitinated proteins, having the potential to trigger the apoptotic response. In contrast, prolonged and sustained HRI-mediated eIF2α phosphorylation can induce cell death, which may involve ATF4 and CHOP expression. Altogether, these studies suggest that HRI-mediated eIF2α phosphorylation may be cytoprotective or cytotoxic depending on the cells, type, and duration of pharmacological agents used. It is thus hypothesized that both HRI activators, inducing eIF2α phosphorylation or HRI inhibitors causing disturbances in eIF2α phosphorylation, may be effective as novel strategies in cancer treatment if the balance in eIF2α phosphorylation is shifted in favor of autophagic or apoptotic response in cancer cells. It is here aimed to review the role of HRI in various biological mechanisms as well as the therapeutic potentials of recently developed HRI activators and inhibitors, targeting eIF2α phosphorylation in cancer cells.
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Affiliation(s)
- Azmi Yerlikaya
- Department of Medical Biology, Faculty of Medicine, Kutahya Health Sciences University, Kutahya, Turkey.
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7
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Davidson S, Yu CH, Steiner A, Ebstein F, Baker PJ, Jarur-Chamy V, Hrovat Schaale K, Laohamonthonkul P, Kong K, Calleja DJ, Harapas CR, Balka KR, Mitchell J, Jackson JT, Geoghegan ND, Moghaddas F, Rogers KL, Mayer-Barber KD, De Jesus AA, De Nardo D, Kile BT, Sadler AJ, Poli MC, Krüger E, Goldbach Mansky R, Masters SL. Protein kinase R is an innate immune sensor of proteotoxic stress via accumulation of cytoplasmic IL-24. Sci Immunol 2022; 7:eabi6763. [PMID: 35148201 PMCID: PMC11036408 DOI: 10.1126/sciimmunol.abi6763] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Proteasome dysfunction can lead to autoinflammatory disease associated with elevated type I interferon (IFN-αβ) and NF-κB signaling; however, the innate immune pathway driving this is currently unknown. Here, we identified protein kinase R (PKR) as an innate immune sensor for proteotoxic stress. PKR activation was observed in cellular models of decreased proteasome function and in multiple cell types from patients with proteasome-associated autoinflammatory disease (PRAAS). Furthermore, genetic deletion or small-molecule inhibition of PKR in vitro ameliorated inflammation driven by proteasome deficiency. In vivo, proteasome inhibitor-induced inflammatory gene transcription was blunted in PKR-deficient mice compared with littermate controls. PKR also acted as a rheostat for proteotoxic stress by triggering phosphorylation of eIF2α, which can prevent the translation of new proteins to restore homeostasis. Although traditionally known as a sensor of RNA, under conditions of proteasome dysfunction, PKR sensed the cytoplasmic accumulation of a known interactor, interleukin-24 (IL-24). When misfolded IL-24 egress into the cytosol was blocked by inhibition of the endoplasmic reticulum-associated degradation pathway, PKR activation and subsequent inflammatory signaling were blunted. Cytokines such as IL-24 are normally secreted from cells; therefore, cytoplasmic accumulation of IL-24 represents an internal danger-associated molecular pattern. Thus, we have identified a mechanism by which proteotoxic stress is detected, causing inflammation observed in the disease PRAAS.
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Affiliation(s)
- Sophia Davidson
- Inflammation Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Chien-Hsiung Yu
- Inflammation Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Annemarie Steiner
- Inflammation Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia
- Institute of Structural Biology, University Hospital Bonn, Bonn 53127, Germany
| | - Frédéric Ebstein
- University Medicine Greifswald, Institute of Medical Biochemistry and Molecular Biology, Greifswald 17475, Germany
| | - Paul J. Baker
- Inflammation and Innate Immunity Unit, Laboratory of Clinical Immunology and Microbiology, NIAID, NIH, Bethesda, MD 20892, USA
| | - Valentina Jarur-Chamy
- Immunogenetics and Translational Immunology Program. Facultad de Medicina, Universidad del Desarrollo Clínica Alemana, Santiago, Chile
| | - Katja Hrovat Schaale
- Inflammation Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Pawat Laohamonthonkul
- Inflammation Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Klara Kong
- Inflammation Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Dale J. Calleja
- Ubiquitin Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Cassandra R. Harapas
- Inflammation Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Katherine R. Balka
- Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Jacob Mitchell
- Translational Autoinflammatory Disease Studies (TADS), Laboratory of Clinical Immunology and Microbiology, NIAID, NIH, Bethesda, MD 20892, USA
| | - Jacob T. Jackson
- Immunology Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Niall D. Geoghegan
- Centre for Dynamic Imaging, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Fiona Moghaddas
- Inflammation Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Kelly L. Rogers
- Centre for Dynamic Imaging, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Katrin D. Mayer-Barber
- Inflammation and Innate Immunity Unit, Laboratory of Clinical Immunology and Microbiology, NIAID, NIH, Bethesda, MD 20892, USA
| | - Adriana A. De Jesus
- Translational Autoinflammatory Disease Studies (TADS), Laboratory of Clinical Immunology and Microbiology, NIAID, NIH, Bethesda, MD 20892, USA
| | - Dominic De Nardo
- Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Benjamin T. Kile
- Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, South Australia 5000, Australia
| | - Anthony J. Sadler
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Molecular and Translational Sciences, Monash University, Clayton, Victoria, Australia
| | - M. Cecilia Poli
- Immunogenetics and Translational Immunology Program. Facultad de Medicina, Universidad del Desarrollo Clínica Alemana, Santiago, Chile
- Division of Pediatric Immunology, Allergy, and Rheumatology, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Elke Krüger
- University Medicine Greifswald, Institute of Medical Biochemistry and Molecular Biology, Greifswald 17475, Germany
| | - Raphaela Goldbach Mansky
- Translational Autoinflammatory Disease Studies (TADS), Laboratory of Clinical Immunology and Microbiology, NIAID, NIH, Bethesda, MD 20892, USA
| | - Seth L. Masters
- Inflammation Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia
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8
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Murugan NJ, Voutsadakis IA. Proteasome regulators in pancreatic cancer. World J Gastrointest Oncol 2022; 14:38-54. [PMID: 35116102 PMCID: PMC8790418 DOI: 10.4251/wjgo.v14.i1.38] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/14/2021] [Accepted: 12/02/2021] [Indexed: 02/06/2023] Open
Abstract
Pancreatic adenocarcinoma is one of the most lethal cancers with rising incidence. Despite progress in its treatment, with the introduction of more effective chemotherapy regimens in the last decade, prognosis of metastatic disease remains inferior to other cancers with long term survival being the exception. Molecular characterization of pancreatic cancer has elucidated the landscape of the disease and has revealed common lesions that contribute to pancreatic carcinogenesis. Regulation of proteostasis is critical in cancers due to increased protein turnover required to support the intense metabolism of cancer cells. The proteasome is an integral part of this regulation and is regulated, in its turn, by key transcription factors, which induce transcription of proteasome structural units. These include FOXO family transcription factors, NFE2L2, hHSF1 and hHSF2, and NF-Y. Networks that encompass proteasome regulators and transduction pathways dysregulated in pancreatic cancer such as the KRAS/ BRAF/MAPK and the Transforming growth factor beta/SMAD pathway contribute to pancreatic cancer progression. This review discusses the proteasome and its transcription factors within the pancreatic cancer cellular micro-environment. We also consider the role of stemness in carcinogenesis and the use of proteasome inhibitors as therapeutic agents.
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Affiliation(s)
- Nirosha J Murugan
- Department of Biology, Algoma University, Sault Sainte Marie P6A3T6, ON, Canada
| | - Ioannis A Voutsadakis
- Department of Medical Oncology, Sault Area Hospital, Sault Sainte Marie P6A3T6, ON, Canada
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9
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Chen N, Zheng Q, Wan G, Guo F, Zeng X, Shi P. Impact of posttranslational modifications in pancreatic carcinogenesis and treatments. Cancer Metastasis Rev 2021; 40:739-759. [PMID: 34342796 DOI: 10.1007/s10555-021-09980-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 07/06/2021] [Indexed: 01/22/2023]
Abstract
Pancreatic cancer (PC) is a highly aggressive cancer, with a 9% 5-year survival rate and a high risk of recurrence. In part, this is because PC is composed of heterogeneous subgroups with different biological and functional characteristics and personalized anticancer treatments are required. Posttranslational modifications (PTMs) play an important role in modifying protein functions/roles and are required for the maintenance of cell viability and biological processes; thus, their dysregulation can lead to disease. Different types of PTMs increase the functional diversity of the proteome, which subsequently influences most aspects of normal cell biology or pathogenesis. This review primarily focuses on ubiquitination, SUMOylation, and NEDDylation, as well as the current understanding of their roles and molecular mechanisms in pancreatic carcinogenesis. Additionally, we briefly summarize studies and clinical trials on PC treatments to advance our knowledge of drugs available to target the ubiquitination, SUMOylation, and NEDDylation PTM types. Further investigation of PTMs could be a critical field of study in relation to PC, as they have been implicated in the initiation and progression of many other types of cancer.
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Affiliation(s)
- Nianhong Chen
- Center Lab of Longhua Branch and Department of Infectious Disease, Shenzhen People's Hospital, 2Nd Clinical Medical College, Jinan University, Guangzhou, People's Republic of China.
- Guangdong Provincial Key Laboratory of Regional Immunity and Diseases, Medicine School, Guangdong Province, Shenzhen University, Shenzhen, 518037, People's Republic of China.
- Department of Cell Biology & University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA.
- Laboratory of Signal Transduction, Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA.
| | - Qiaoqiao Zheng
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Guoqing Wan
- Center Lab of Longhua Branch and Department of Infectious Disease, Shenzhen People's Hospital, 2Nd Clinical Medical College, Jinan University, Guangzhou, People's Republic of China
- Guangdong Provincial Key Laboratory of Regional Immunity and Diseases, Medicine School, Guangdong Province, Shenzhen University, Shenzhen, 518037, People's Republic of China
| | - Feng Guo
- Department of Medicine, Stanford School of Medicine, Stanford, CA, 94305, USA
| | - Xiaobin Zeng
- Center Lab of Longhua Branch and Department of Infectious Disease, Shenzhen People's Hospital, 2Nd Clinical Medical College, Jinan University, Guangzhou, People's Republic of China.
- Guangdong Provincial Key Laboratory of Regional Immunity and Diseases, Medicine School, Guangdong Province, Shenzhen University, Shenzhen, 518037, People's Republic of China.
| | - Ping Shi
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China.
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10
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Sannino S, Yates ME, Schurdak ME, Oesterreich S, Lee AV, Wipf P, Brodsky JL. Unique integrated stress response sensors regulate cancer cell susceptibility when Hsp70 activity is compromised. eLife 2021; 10:64977. [PMID: 34180400 PMCID: PMC8275131 DOI: 10.7554/elife.64977] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 06/27/2021] [Indexed: 12/11/2022] Open
Abstract
Molecular chaperones, such as Hsp70, prevent proteotoxicity and maintain homeostasis. This is perhaps most evident in cancer cells, which overexpress Hsp70 and thrive even when harboring high levels of misfolded proteins. To define the response to proteotoxic challenges, we examined adaptive responses in breast cancer cells in the presence of an Hsp70 inhibitor. We discovered that the cells bin into distinct classes based on inhibitor sensitivity. Strikingly, the most resistant cells have higher autophagy levels, and autophagy was maximally activated only in resistant cells upon Hsp70 inhibition. In turn, resistance to compromised Hsp70 function required the integrated stress response transducer, GCN2, which is commonly associated with amino acid starvation. In contrast, sensitive cells succumbed to Hsp70 inhibition by activating PERK. These data reveal an unexpected route through which breast cancer cells adapt to proteotoxic insults and position GCN2 and autophagy as complementary mechanisms to ensure survival when proteostasis is compromised.
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Affiliation(s)
- Sara Sannino
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, United States
| | - Megan E Yates
- Women's Cancer Research Center, UPMC Hillman Cancer Center, Magee-Women Research Institute, Pittsburgh, United States.,Integrative Systems Biology Program, University of Pittsburgh, Pittsburgh, United States.,Medical Scientist Training Program, University of Pittsburgh School of Medicine, Pittsburgh, United States
| | - Mark E Schurdak
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, United States.,University of Pittsburgh Drug Discovery Institute, Pittsburgh, United States
| | - Steffi Oesterreich
- Women's Cancer Research Center, UPMC Hillman Cancer Center, Magee-Women Research Institute, Pittsburgh, United States.,Integrative Systems Biology Program, University of Pittsburgh, Pittsburgh, United States.,Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, United States
| | - Adrian V Lee
- Women's Cancer Research Center, UPMC Hillman Cancer Center, Magee-Women Research Institute, Pittsburgh, United States.,Integrative Systems Biology Program, University of Pittsburgh, Pittsburgh, United States.,Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, United States
| | - Peter Wipf
- Department of Chemistry, University of Pittsburgh, Pittsburgh, United States
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, United States
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11
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Reovirus and the Host Integrated Stress Response: On the Frontlines of the Battle to Survive. Viruses 2021; 13:v13020200. [PMID: 33525628 PMCID: PMC7910986 DOI: 10.3390/v13020200] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/22/2021] [Accepted: 01/26/2021] [Indexed: 12/17/2022] Open
Abstract
Cells are continually exposed to stressful events, which are overcome by the activation of a number of genetic pathways. The integrated stress response (ISR) is a large component of the overall cellular response to stress, which ultimately functions through the phosphorylation of the alpha subunit of eukaryotic initiation factor-2 (eIF2α) to inhibit the energy-taxing process of translation. This response is instrumental in the inhibition of viral infection and contributes to evolution in viruses. Mammalian orthoreovirus (MRV), an oncolytic virus that has shown promise in over 30 phase I–III clinical trials, has been shown to induce multiple arms within the ISR pathway, but it successfully evades, modulates, or subverts each cellular attempt to inhibit viral translation. MRV has not yet received Food and Drug Administration (FDA) approval for general use in the clinic; therefore, researchers continue to study virus interactions with host cells to identify circumstances where MRV effectiveness in tumor killing can be improved. In this review, we will discuss the ISR, MRV modulation of the ISR, and discuss ways in which MRV interaction with the ISR may increase the effectiveness of cancer therapeutics whose modes of action are altered by the ISR.
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12
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Smith RCL, Kanellos G, Vlahov N, Alexandrou C, Willis AE, Knight JRP, Sansom OJ. Translation initiation in cancer at a glance. J Cell Sci 2021; 134:jcs248476. [PMID: 33441326 DOI: 10.1242/jcs.248476] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cell division, differentiation and function are largely dependent on accurate proteome composition and regulated gene expression. To control this, protein synthesis is an intricate process governed by upstream signalling pathways. Eukaryotic translation is a multistep process and can be separated into four distinct phases: initiation, elongation, termination and recycling of ribosomal subunits. Translation initiation, the focus of this article, is highly regulated to control the activity and/or function of eukaryotic initiation factors (eIFs) and permit recruitment of mRNAs to the ribosomes. In this Cell Science at a Glance and accompanying poster, we outline the mechanisms by which tumour cells alter the process of translation initiation and discuss how this benefits tumour formation, proliferation and metastasis.
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Affiliation(s)
- Rachael C L Smith
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
- Institute of Cancer Sciences, University of Glasgow, G61 1QH, UK
| | - Georgios Kanellos
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
| | - Nikola Vlahov
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
| | | | - Anne E Willis
- MRC Toxicology Unit, University of Cambridge, Cambridge CB2 1QW, UK
| | - John R P Knight
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
| | - Owen J Sansom
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
- Institute of Cancer Sciences, University of Glasgow, G61 1QH, UK
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13
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Mukherjee T, Ramaglia V, Abdel-Nour M, Bianchi AA, Tsalikis J, Chau HN, Kalia SK, Kalia LV, Chen JJ, Arnoult D, Gommerman JL, Philpott DJ, Girardin SE. The eIF2α kinase HRI triggers the autophagic clearance of cytosolic protein aggregates. J Biol Chem 2021; 296:100050. [PMID: 33168630 PMCID: PMC7948985 DOI: 10.1074/jbc.ra120.014415] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 10/27/2020] [Accepted: 11/09/2020] [Indexed: 12/21/2022] Open
Abstract
Large cytosolic protein aggregates are removed by two main cellular processes, autophagy and the ubiquitin-proteasome system, and defective clearance of these protein aggregates results in proteotoxicity and cell death. Recently, we found that the eIF2α kinase heme-regulated inhibitory (HRI) induced a cytosolic unfolded protein response to prevent aggregation of innate immune signalosomes, but whether HRI acts as a general sensor of proteotoxicity in the cytosol remains unclear. Here we show that HRI controls autophagy to clear cytosolic protein aggregates when the ubiquitin-proteasome system is inhibited. We further report that silencing the expression of HRI resulted in decreased levels of BAG3 and HSPB8, two proteins involved in chaperone-assisted selective autophagy, suggesting that HRI may control proteostasis in the cytosol at least in part through chaperone-assisted selective autophagy. Moreover, knocking down the expression of HRI resulted in cytotoxic accumulation of overexpressed α-synuclein, a protein known to aggregate in Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. In agreement with these data, protein aggregate accumulation and microglia activation were observed in the spinal cord white matter of 7-month-old Hri-/- mice as compared with Hri+/+ littermates. Moreover, aged Hri-/- mice showed accumulation of misfolded α-synuclein in the lateral collateral pathway, a region of the sacral spinal cord horn that receives visceral sensory afferents from the bladder and distal colon, a pathological feature common to α-synucleinopathies in humans. Together, these results suggest that HRI contributes to a general cytosolic unfolded protein response that could be leveraged to bolster the clearance of cytotoxic protein aggregates.
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Affiliation(s)
- Tapas Mukherjee
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada; Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Valeria Ramaglia
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Mena Abdel-Nour
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Athanasia A Bianchi
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Jessica Tsalikis
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Hien N Chau
- Krembil Research Institute, Toronto Western Hospital, University Health Network, Toronto, Canada
| | - Suneil K Kalia
- Krembil Research Institute, Toronto Western Hospital, University Health Network, Toronto, Canada
| | - Lorraine V Kalia
- Krembil Research Institute, Toronto Western Hospital, University Health Network, Toronto, Canada
| | - Jane-Jane Chen
- Institute of Medical Engineering & Science, MIT, Cambridge, Massachusetts, USA
| | - Damien Arnoult
- INSERM U1197, Hôpital Paul Brousse, Bâtiment Lavoisier, Villejuif Cedex, France; Université Paris-Saclay, Paris, France
| | | | - Dana J Philpott
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Stephen E Girardin
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada; Department of Immunology, University of Toronto, Toronto, Ontario, Canada.
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14
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Proteotoxic Stress and Cell Death in Cancer Cells. Cancers (Basel) 2020; 12:cancers12092385. [PMID: 32842524 PMCID: PMC7563887 DOI: 10.3390/cancers12092385] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/19/2020] [Accepted: 08/20/2020] [Indexed: 02/06/2023] Open
Abstract
To maintain proteostasis, cells must integrate information and activities that supervise protein synthesis, protein folding, conformational stability, and also protein degradation. Extrinsic and intrinsic conditions can both impact normal proteostasis, causing the appearance of proteotoxic stress. Initially, proteotoxic stress elicits adaptive responses aimed at restoring proteostasis, allowing cells to survive the stress condition. However, if the proteostasis restoration fails, a permanent and sustained proteotoxic stress can be deleterious, and cell death ensues. Many cancer cells convive with high levels of proteotoxic stress, and this condition could be exploited from a therapeutic perspective. Understanding the cell death pathways engaged by proteotoxic stress is instrumental to better hijack the proliferative fate of cancer cells.
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15
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Pellegrini P, Selvaraju K, Faustini E, Mofers A, Zhang X, Ternerot J, Schubert A, Linder S, D′Arcy P. Induction of ER Stress in Acute Lymphoblastic Leukemia Cells by the Deubiquitinase Inhibitor VLX1570. Int J Mol Sci 2020; 21:ijms21134757. [PMID: 32635430 PMCID: PMC7369842 DOI: 10.3390/ijms21134757] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 07/02/2020] [Indexed: 02/08/2023] Open
Abstract
The proteasome is a validated target of cancer therapeutics. Inhibition of proteasome activity results in the activation of the unfolded protein response (UPR) characterized by phosphorylation of eukaryotic initiation factor 2α (eIF2α), global translational arrest, and increased expression of the proapoptotic CHOP (C/EBP homologous protein) protein. Defects in the UPR response has been reported to result in altered sensitivity of tumor cells to proteasome inhibitors. Here, we characterized the effects of the deubiquitinase (DUB) inhibitor VLX1570 on protein homeostasis, both at the level of the UPR and on protein translation, in acute lymphoblastic leukemia (ALL). Similar to the 20S inhibitor bortezomib, VLX1570 induced accumulation of polyubiquitinated proteins and increased expression of the chaperone Grp78/Bip in ALL cells. Both compounds induced cleavage of PARP (Poly (ADP-ribose) polymerase) in ALL cells, consistent with induction of apoptosis. However, and in contrast to bortezomib, VLX1570 treatment resulted in limited induction of the proapoptotic CHOP protein. Translational inhibition was observed by both bortezomib and VLX1570. We report that in distinction to bortezomib, suppression of translation by VXL1570 occurred at the level of elongation. Increased levels of Hsc70/Hsp70 proteins were observed on polysomes following exposure to VLX1570, possibly suggesting defects in nascent protein folding. Our findings demonstrate apoptosis induction in ALL cells that appears to be uncoupled from CHOP induction, and show that VLX1570 suppresses protein translation by a mechanism distinct from that of bortezomib.
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Affiliation(s)
- Paola Pellegrini
- Department of Biomedical and Clinical Sciences, Linköping University, S-58183 Linköping, Sweden; (P.P.); (K.S.); (E.F.); (A.M.); (J.T.); (A.S.); (S.L.)
| | - Karthik Selvaraju
- Department of Biomedical and Clinical Sciences, Linköping University, S-58183 Linköping, Sweden; (P.P.); (K.S.); (E.F.); (A.M.); (J.T.); (A.S.); (S.L.)
| | - Elena Faustini
- Department of Biomedical and Clinical Sciences, Linköping University, S-58183 Linköping, Sweden; (P.P.); (K.S.); (E.F.); (A.M.); (J.T.); (A.S.); (S.L.)
| | - Arjan Mofers
- Department of Biomedical and Clinical Sciences, Linköping University, S-58183 Linköping, Sweden; (P.P.); (K.S.); (E.F.); (A.M.); (J.T.); (A.S.); (S.L.)
| | - Xiaonan Zhang
- Department of Immunology, Genetics and Pathology, Uppsala University, 751 85 Uppsala, Sweden;
| | - Jens Ternerot
- Department of Biomedical and Clinical Sciences, Linköping University, S-58183 Linköping, Sweden; (P.P.); (K.S.); (E.F.); (A.M.); (J.T.); (A.S.); (S.L.)
| | - Alice Schubert
- Department of Biomedical and Clinical Sciences, Linköping University, S-58183 Linköping, Sweden; (P.P.); (K.S.); (E.F.); (A.M.); (J.T.); (A.S.); (S.L.)
| | - Stig Linder
- Department of Biomedical and Clinical Sciences, Linköping University, S-58183 Linköping, Sweden; (P.P.); (K.S.); (E.F.); (A.M.); (J.T.); (A.S.); (S.L.)
- Department of Oncology-Pathology, Karolinska Institute, S-17176 Stockholm, Sweden
| | - Pádraig D′Arcy
- Department of Biomedical and Clinical Sciences, Linköping University, S-58183 Linköping, Sweden; (P.P.); (K.S.); (E.F.); (A.M.); (J.T.); (A.S.); (S.L.)
- Correspondence:
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16
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Heme-regulated eIF2α kinase in erythropoiesis and hemoglobinopathies. Blood 2020; 134:1697-1707. [PMID: 31554636 DOI: 10.1182/blood.2019001915] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 09/11/2019] [Indexed: 12/12/2022] Open
Abstract
As essential components of hemoglobin, iron and heme play central roles in terminal erythropoiesis. The impairment of this process in iron/heme deficiency results in microcytic hypochromic anemia, the most prevalent anemia globally. Heme-regulated eIF2α kinase, also known as heme-regulated inhibitor (HRI), is a key heme-binding protein that senses intracellular heme concentrations to balance globin protein synthesis with the amount of heme available for hemoglobin production. HRI is activated during heme deficiency to phosphorylate eIF2α (eIF2αP), which simultaneously inhibits the translation of globin messenger RNAs (mRNAs) and selectively enhances the translation of activating transcription factor 4 (ATF4) mRNA to induce stress response genes. This coordinated translational regulation is a universal hallmark across the eIF2α kinase family under various stress conditions and is termed the integrated stress response (ISR). Inhibition of general protein synthesis by HRI-eIF2αP in erythroblasts is necessary to prevent proteotoxicity and maintain protein homeostasis in the cytoplasm and mitochondria. Additionally, the HRI-eIF2αP-ATF4 pathway represses mechanistic target of rapamycin complex 1 (mTORC1) signaling, specifically in the erythroid lineage as a feedback mechanism of erythropoietin-stimulated erythropoiesis during iron/heme deficiency. Furthermore, ATF4 target genes are most highly activated during iron deficiency to maintain mitochondrial function and redox homeostasis, as well as to enable erythroid differentiation. Thus, heme and translation regulate erythropoiesis through 2 key signaling pathways, ISR and mTORC1, which are coordinated by HRI to circumvent ineffective erythropoiesis (IE). HRI-ISR is also activated to reduce the severity of β-thalassemia intermedia in the Hbbth1/th1 murine model. Recently, HRI has been implicated in the regulation of human fetal hemoglobin production. Therefore, HRI-ISR has emerged as a potential therapeutic target for hemoglobinopathies.
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17
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Szwed M, Sønstevold T, Øverbye A, Engedal N, Grallert B, Mørch Ý, Sulheim E, Iversen TG, Skotland T, Sandvig K, Torgersen ML. Small variations in nanoparticle structure dictate differential cellular stress responses and mode of cell death. Nanotoxicology 2019; 13:761-782. [PMID: 30760074 DOI: 10.1080/17435390.2019.1576238] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
For optimal exploitation of nanoparticles (NPs) in biomedicine, and to predict nanotoxicity, detailed knowledge of the cellular responses to cell-bound or internalized NPs is imperative. The final outcome of NP-cell interaction is dictated by the type and magnitude of the NP insult and the cellular response. Here, this has been systematically studied by using poly(alkylcyanoacrylate) (PACA) particles differing only in their alkyl side chains; butyl (PBCA), ethylbutyl (PEBCA), or octyl (POCA), respectively. Surprisingly, these highly similar NPs induced different stress responses and modes of cell death in human cell lines. The POCA particles generally induced endoplasmic reticulum stress and apoptosis. In contrast, PBCA and PEBCA particles induced oxidative stress and lipid peroxidation depending on the level of the glutathione precursor cystine and transcription of the cystine transporter SLC7A11. The latter was induced as a protective response by the transcription factors ATF4 and Nrf2. PBCA particles strongly activated ATF4 downstream of the eIF2α kinase HRI, whereas PEBCA particles more potently induced Nrf2 antioxidant responses. Intriguingly, PBCA particles activated the cell death mechanism ferroptosis; a promising option for targeting multidrug-resistant cancers. Our findings highlight that even minor differences in NP composition can severely impact the cellular response to NPs. This may have important implications in therapeutic settings.
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Affiliation(s)
- Marzena Szwed
- a Department of Molecular Cell Biology , Institute for Cancer Research, Oslo University Hospital , Oslo , Norway
| | - Tonje Sønstevold
- a Department of Molecular Cell Biology , Institute for Cancer Research, Oslo University Hospital , Oslo , Norway.,b Faculty of Mathematics and Natural Sciences, Department of Biosciences , University of Oslo , Oslo , Norway
| | - Anders Øverbye
- a Department of Molecular Cell Biology , Institute for Cancer Research, Oslo University Hospital , Oslo , Norway
| | - Nikolai Engedal
- c Centre for Molecular Medicine Norway (NCMM), Nordic EMBL Partnership, University of Oslo , Oslo , Norway
| | - Beata Grallert
- d Department of Radiation Biology , Institute for Cancer Research, Oslo University Hospital , Oslo , Norway
| | - Ýrr Mørch
- e Department of Biotechnology and Nanomedicine , SINTEF AS , Trondheim , Norway
| | - Einar Sulheim
- e Department of Biotechnology and Nanomedicine , SINTEF AS , Trondheim , Norway.,f Faculty of Natural Sciences, Department of Physics , The Norwegian University of Science and Technology (NTNU) , Trondheim , Norway
| | - Tore-Geir Iversen
- a Department of Molecular Cell Biology , Institute for Cancer Research, Oslo University Hospital , Oslo , Norway
| | - Tore Skotland
- a Department of Molecular Cell Biology , Institute for Cancer Research, Oslo University Hospital , Oslo , Norway
| | - Kirsten Sandvig
- a Department of Molecular Cell Biology , Institute for Cancer Research, Oslo University Hospital , Oslo , Norway.,b Faculty of Mathematics and Natural Sciences, Department of Biosciences , University of Oslo , Oslo , Norway
| | - Maria L Torgersen
- a Department of Molecular Cell Biology , Institute for Cancer Research, Oslo University Hospital , Oslo , Norway
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