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Kazanietz MG, Cooke M. Protein kinase C signaling "in" and "to" the nucleus: Master kinases in transcriptional regulation. J Biol Chem 2024; 300:105692. [PMID: 38301892 PMCID: PMC10907189 DOI: 10.1016/j.jbc.2024.105692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 01/08/2024] [Accepted: 01/09/2024] [Indexed: 02/03/2024] Open
Abstract
PKC is a multifunctional family of Ser-Thr kinases widely implicated in the regulation of fundamental cellular functions, including proliferation, polarity, motility, and differentiation. Notwithstanding their primary cytoplasmic localization and stringent activation by cell surface receptors, PKC isozymes impel prominent nuclear signaling ultimately impacting gene expression. While transcriptional regulation may be wielded by nuclear PKCs, it most often relies on cytoplasmic phosphorylation events that result in nuclear shuttling of PKC downstream effectors, including transcription factors. As expected from the unique coupling of PKC isozymes to signaling effector pathways, glaring disparities in gene activation/repression are observed upon targeting individual PKC family members. Notably, specific PKCs control the expression and activation of transcription factors implicated in cell cycle/mitogenesis, epithelial-to-mesenchymal transition and immune function. Additionally, PKCs isozymes tightly regulate transcription factors involved in stepwise differentiation of pluripotent stem cells toward specific epithelial, mesenchymal, and hematopoietic cell lineages. Aberrant PKC expression and/or activation in pathological conditions, such as in cancer, leads to profound alterations in gene expression, leading to an extensive rewiring of transcriptional networks associated with mitogenesis, invasiveness, stemness, and tumor microenvironment dysregulation. In this review, we outline the current understanding of PKC signaling "in" and "to" the nucleus, with significant focus on established paradigms of PKC-mediated transcriptional control. Dissecting these complexities would allow the identification of relevant molecular targets implicated in a wide spectrum of diseases.
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Affiliation(s)
- Marcelo G Kazanietz
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
| | - Mariana Cooke
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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2
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Affandi T, Haas A, Ohm AM, Wright GM, Black JC, Reyland ME. PKCδ Regulates Chromatin Remodeling and DNA Repair through SIRT6. Mol Cancer Res 2024; 22:181-196. [PMID: 37889141 PMCID: PMC10872792 DOI: 10.1158/1541-7786.mcr-23-0493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 09/07/2023] [Accepted: 10/25/2023] [Indexed: 10/28/2023]
Abstract
Irradiation (IR) is a highly effective cancer therapy; however, IR damage to tumor-adjacent healthy tissues can result in significant comorbidities and potentially limit the course of therapy. We have previously shown that protein kinase C delta (PKCδ) is required for IR-induced apoptosis and that inhibition of PKCδ activity provides radioprotection in vivo. Here we show that PKCδ regulates histone modification, chromatin accessibility, and double-stranded break (DSB) repair through a mechanism that requires Sirtuin 6 (SIRT6). Overexpression of PKCδ promotes genomic instability and increases DNA damage and apoptosis. Conversely, depletion of PKCδ increases DNA repair via nonhomologous end joining (NHEJ) and homologous recombination (HR) as evidenced by increased formation of DNA damage foci, increased expression of DNA repair proteins, and increased repair of NHEJ and HR fluorescent reporter constructs. Nuclease sensitivity indicates that PKCδ depletion is associated with more open chromatin, while overexpression of PKCδ reduces chromatin accessibility. Epiproteome analysis reveals increased chromatin associated H3K36me2 in PKCδ-depleted cells which is accompanied by chromatin disassociation of KDM2A. We identify SIRT6 as a downstream mediator of PKCδ. PKCδ-depleted cells have increased SIRT6 expression, and depletion of SIRT6 reverses changes in chromatin accessibility, histone modification and DSB repair in PKCδ-depleted cells. Furthermore, depletion of SIRT6 reverses radioprotection in PKCδ-depleted cells. Our studies describe a novel pathway whereby PKCδ orchestrates SIRT6-dependent changes in chromatin accessibility to regulate DNA repair, and define a mechanism for regulation of radiation-induced apoptosis by PKCδ. IMPLICATIONS PKCδ controls sensitivity to irradiation by regulating DNA repair.
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Affiliation(s)
- Trisiani Affandi
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Ami Haas
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Angela M. Ohm
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Gregory M. Wright
- Department of Pharmacology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Joshua C. Black
- Department of Pharmacology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Mary E. Reyland
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
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3
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Silnitsky S, Rubin SJS, Zerihun M, Qvit N. An Update on Protein Kinases as Therapeutic Targets-Part I: Protein Kinase C Activation and Its Role in Cancer and Cardiovascular Diseases. Int J Mol Sci 2023; 24:17600. [PMID: 38139428 PMCID: PMC10743896 DOI: 10.3390/ijms242417600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 12/10/2023] [Accepted: 12/12/2023] [Indexed: 12/24/2023] Open
Abstract
Protein kinases are one of the most significant drug targets in the human proteome, historically harnessed for the treatment of cancer, cardiovascular disease, and a growing number of other conditions, including autoimmune and inflammatory processes. Since the approval of the first kinase inhibitors in the late 1990s and early 2000s, the field has grown exponentially, comprising 98 approved therapeutics to date, 37 of which were approved between 2016 and 2021. While many of these small-molecule protein kinase inhibitors that interact orthosterically with the protein kinase ATP binding pocket have been massively successful for oncological indications, their poor selectively for protein kinase isozymes have limited them due to toxicities in their application to other disease spaces. Thus, recent attention has turned to the use of alternative allosteric binding mechanisms and improved drug platforms such as modified peptides to design protein kinase modulators with enhanced selectivity and other pharmacological properties. Herein we review the role of different protein kinase C (PKC) isoforms in cancer and cardiovascular disease, with particular attention to PKC-family inhibitors. We discuss translational examples and carefully consider the advantages and limitations of each compound (Part I). We also discuss the recent advances in the field of protein kinase modulators, leverage molecular docking to model inhibitor-kinase interactions, and propose mechanisms of action that will aid in the design of next-generation protein kinase modulators (Part II).
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Affiliation(s)
- Shmuel Silnitsky
- The Azrieli Faculty of Medicine in the Galilee, Bar-Ilan University, Henrietta Szold St. 8, Safed 1311502, Israel; (S.S.); (M.Z.)
| | - Samuel J. S. Rubin
- Department of Medicine, School of Medicine, Stanford University, 300 Pasteur Drive, Stanford, CA 94305, USA;
| | - Mulate Zerihun
- The Azrieli Faculty of Medicine in the Galilee, Bar-Ilan University, Henrietta Szold St. 8, Safed 1311502, Israel; (S.S.); (M.Z.)
| | - Nir Qvit
- The Azrieli Faculty of Medicine in the Galilee, Bar-Ilan University, Henrietta Szold St. 8, Safed 1311502, Israel; (S.S.); (M.Z.)
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4
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Saiz-Baggetto S, Dolz-Edo L, Méndez E, García-Bolufer P, Marí M, Bañó MC, Fariñas I, Morante-Redolat JM, Igual JC, Quilis I. A Multimodel Study of the Role of Novel PKC Isoforms in the DNA Integrity Checkpoint. Int J Mol Sci 2023; 24:15796. [PMID: 37958781 PMCID: PMC10650207 DOI: 10.3390/ijms242115796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 10/22/2023] [Accepted: 10/29/2023] [Indexed: 11/15/2023] Open
Abstract
The protein kinase C (PKC) family plays important regulatory roles in numerous cellular processes. Saccharomyces cerevisiae contains a single PKC, Pkc1, whereas in mammals, the PKC family comprises nine isoforms. Both Pkc1 and the novel isoform PKCδ are involved in the control of DNA integrity checkpoint activation, demonstrating that this mechanism is conserved from yeast to mammals. To explore the function of PKCδ in a non-tumor cell line, we employed CRISPR-Cas9 technology to obtain PKCδ knocked-out mouse embryonic stem cells (mESCs). This model demonstrated that the absence of PKCδ reduced the activation of the effector kinase CHK1, although it suggested that other isoform(s) might contribute to this function. Therefore, we used yeast to study the ability of each single PKC isoform to activate the DNA integrity checkpoint. Our analysis identified that PKCθ, the closest isoform to PKCδ, was also able to perform this function, although with less efficiency. Then, by generating truncated and mutant versions in key residues, we uncovered differences between the activation mechanisms of PKCδ and PKCθ and identified their essential domains. Our work strongly supports the role of PKC as a key player in the DNA integrity checkpoint pathway and highlights the advantages of combining distinct research models.
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Affiliation(s)
- Sara Saiz-Baggetto
- Departament de Bioquímica i Biologia Molecular, Universitat de València, 46100 Burjassot, Spain; (S.S.-B.); (L.D.-E.); (M.C.B.)
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, 46100 Burjassot, Spain (I.F.); (J.M.M.-R.)
| | - Laura Dolz-Edo
- Departament de Bioquímica i Biologia Molecular, Universitat de València, 46100 Burjassot, Spain; (S.S.-B.); (L.D.-E.); (M.C.B.)
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, 46100 Burjassot, Spain (I.F.); (J.M.M.-R.)
- Departament de Biologia Cellular, Biologia Funcional i Antropologia Física, Universitat de València, 46100 Burjassot, Spain
| | - Ester Méndez
- Departament de Bioquímica i Biologia Molecular, Universitat de València, 46100 Burjassot, Spain; (S.S.-B.); (L.D.-E.); (M.C.B.)
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, 46100 Burjassot, Spain (I.F.); (J.M.M.-R.)
| | - Pau García-Bolufer
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, 46100 Burjassot, Spain (I.F.); (J.M.M.-R.)
- Departament de Biologia Cellular, Biologia Funcional i Antropologia Física, Universitat de València, 46100 Burjassot, Spain
| | - Miquel Marí
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, 46100 Burjassot, Spain (I.F.); (J.M.M.-R.)
- Departament de Biologia Cellular, Biologia Funcional i Antropologia Física, Universitat de València, 46100 Burjassot, Spain
| | - M. Carmen Bañó
- Departament de Bioquímica i Biologia Molecular, Universitat de València, 46100 Burjassot, Spain; (S.S.-B.); (L.D.-E.); (M.C.B.)
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, 46100 Burjassot, Spain (I.F.); (J.M.M.-R.)
| | - Isabel Fariñas
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, 46100 Burjassot, Spain (I.F.); (J.M.M.-R.)
- Departament de Biologia Cellular, Biologia Funcional i Antropologia Física, Universitat de València, 46100 Burjassot, Spain
| | - José Manuel Morante-Redolat
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, 46100 Burjassot, Spain (I.F.); (J.M.M.-R.)
- Departament de Biologia Cellular, Biologia Funcional i Antropologia Física, Universitat de València, 46100 Burjassot, Spain
| | - J. Carlos Igual
- Departament de Bioquímica i Biologia Molecular, Universitat de València, 46100 Burjassot, Spain; (S.S.-B.); (L.D.-E.); (M.C.B.)
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, 46100 Burjassot, Spain (I.F.); (J.M.M.-R.)
| | - Inma Quilis
- Departament de Bioquímica i Biologia Molecular, Universitat de València, 46100 Burjassot, Spain; (S.S.-B.); (L.D.-E.); (M.C.B.)
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Universitat de València, 46100 Burjassot, Spain (I.F.); (J.M.M.-R.)
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5
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Affandi T, Haas A, Ohm AM, Wright GM, Black JC, Reyland ME. PKCδ regulates chromatin remodeling and DNA repair through SIRT6. bioRxiv 2023:2023.05.24.541991. [PMID: 37292592 PMCID: PMC10245827 DOI: 10.1101/2023.05.24.541991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Protein kinase C delta (PKCδ) is a ubiquitous kinase whose function is defined in part by localization to specific cellular compartments. Nuclear PKCδ is both necessary and sufficient for IR-induced apoptosis, while inhibition of PKCδ activity provides radioprotection in vivo. How nuclear PKCδ regulates DNA-damage induced cell death is poorly understood. Here we show that PKCδ regulates histone modification, chromatin accessibility, and double stranded break (DSB) repair through a mechanism that requires SIRT6. Overexpression of PKCδ promotes genomic instability and increases DNA damage and apoptosis. Conversely, depletion of PKCδ increases DNA repair via non-homologous end joining (NHEJ) and homologous recombination (HR) as evidenced by more rapid formation of NHEJ (DNA-PK) and HR (Rad51) DNA damage foci, increased expression of repair proteins, and increased repair of NHEJ and HR fluorescent reporter constructs. Nuclease sensitivity indicates that PKCδ depletion is associated with more open chromatin, while overexpression of PKCδ reduces chromatin accessibility. Epiproteome analysis revealed that PKCδ depletion increases chromatin associated H3K36me2, and reduces ribosylation of KDM2A and chromatin bound KDM2A. We identify SIRT6 as a downstream mediator of PKCδ. PKCδ-depleted cells have increased expression of SIRT6, and depletion of SIRT6 reverses the changes in chromatin accessibility, histone modification and NHEJ and HR DNA repair seen with PKCδ-depletion. Furthermore, depletion of SIRT6 reverses radioprotection in PKCδ-depleted cells. Our studies describe a novel pathway whereby PKCδ orchestrates SIRT6-dependent changes in chromatin accessibility to increase DNA repair, and define a mechanism for regulation of radiation-induced apoptosis by PKCδ.
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Affiliation(s)
- Trisiani Affandi
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Ami Haas
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Angela M. Ohm
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Gregory M. Wright
- Department of Pharmacology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Joshua C. Black
- Department of Pharmacology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Mary E. Reyland
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
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6
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Yamada K, Motohashi S, Oikawa T, Tago N, Koizumi R, Ono M, Tachibana T, Yoshida A, Yoshida S, Shimoda M, Oka M, Yoneda Y, Yoshida K. Extended-synaptotagmin 1 engages in unconventional protein secretion mediated via SEC22B(+) vesicle pathway in liver cancer. Proc Natl Acad Sci U S A 2022; 119:e2202730119. [PMID: 36044553 DOI: 10.1073/pnas.2202730119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Protein secretion in cancer cells defines tumor survival and progression by orchestrating the microenvironment. Studies suggest the occurrence of active secretion of cytosolic proteins in liver cancer and their involvement in tumorigenesis. Here, we investigated the identification of extended-synaptotagmin 1 (E-Syt1), an endoplasmic reticulum (ER)-bound protein, as a key mediator for cytosolic protein secretion at the ER-plasma membrane (PM) contact sites. Cytosolic proteins interacted with E-Syt1 on the ER, and then localized spatially inside SEC22B+ vesicles of liver cancer cells. Consequently, SEC22B on the vesicle tethered to the PM via Q-SNAREs (SNAP23, SNX3, and SNX4) for their secretion. Furthermore, inhibiting the interaction of protein kinase Cδ (PKCδ), a liver cancer-specific secretory cytosolic protein, with E-Syt1 by a PKCδ antibody, decreased in both PKCδ secretion and tumorigenicity. Results reveal the role of ER-PM contact sites in cytosolic protein secretion and provide a basis for ER-targeting therapy for liver cancer.
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7
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Black JD, Affandi T, Black AR, Reyland ME. PKCα and PKCδ: Friends and Rivals. J Biol Chem 2022; 298:102194. [PMID: 35760100 PMCID: PMC9352922 DOI: 10.1016/j.jbc.2022.102194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 06/13/2022] [Accepted: 06/21/2022] [Indexed: 01/06/2023] Open
Abstract
PKC comprises a large family of serine/threonine kinases that share a requirement for allosteric activation by lipids. While PKC isoforms have significant homology, functional divergence is evident among subfamilies and between individual PKC isoforms within a subfamily. Here, we highlight these differences by comparing the regulation and function of representative PKC isoforms from the conventional (PKCα) and novel (PKCδ) subfamilies. We discuss how unique structural features of PKCα and PKCδ underlie differences in activation and highlight the similar, divergent, and even opposing biological functions of these kinases. We also consider how PKCα and PKCδ can contribute to pathophysiological conditions and discuss challenges to targeting these kinases therapeutically.
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Affiliation(s)
- Jennifer D Black
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE.
| | - Trisiani Affandi
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus
| | - Adrian R Black
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE
| | - Mary E Reyland
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus.
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Yamada K, Kizawa R, Yoshida A, Koizumi R, Motohashi S, Shimoyama Y, Hannya Y, Yoshida S, Oikawa T, Shimoda M, Yoshida K. Extracellular PKCδ signals to EGF receptor for tumor proliferation in liver cancer cells. Cancer Sci 2022; 113:2378-2385. [PMID: 35490382 PMCID: PMC9277411 DOI: 10.1111/cas.15386] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 04/19/2022] [Accepted: 04/25/2022] [Indexed: 12/24/2022] Open
Abstract
Protein kinase C delta (PKCδ) is a multifunctional PKC family member and has been implicated in many types of cancers, including liver cancer. Recently, we have reported that PKCδ is secreted from liver cancer cells, and involved in cell proliferation and tumor growth. However, it remains unclear whether the extracellular PKCδ directly regulates cell surface growth factor receptors. Here, we identify epidermal growth factor receptor (EGFR) as a novel interacting protein of the cell surface PKCδ in liver cancer cells. Imaging studies showed that secreted PKCδ interacted with EGFR‐expressing cells in both autocrine and paracrine manners. Biochemical analysis revealed that PKCδ bound to the extracellular domain of EGFR. We further found that a part of the amino acid sequence on the C‐terminal region of PKCδ was similar to the putative EGFR binding site of EGF. In this regard, the point mutant of PKCδ in the binding site lacked the ability to bind to the extracellular domain of EGFR. Upon an extracellular PKCδ‐EGFR association, ERK1/2 activation, downstream of EGFR signaling, was apparently induced in liver cancer cells. This study indicates that extracellular PKCδ behaves as a growth factor and provides a molecular basis for extracellular PKCδ‐targeting therapy for liver cancer.
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Affiliation(s)
- Kohji Yamada
- Department of Biochemistry The Jikei University School of Medicine 3‐25‐8 Nishi‐Shinbashi, Minato‐ku Tokyo 105‐8461 Japan
| | - Ryusuke Kizawa
- Department of Biochemistry The Jikei University School of Medicine 3‐25‐8 Nishi‐Shinbashi, Minato‐ku Tokyo 105‐8461 Japan
| | - Ayano Yoshida
- Department of Biochemistry The Jikei University School of Medicine 3‐25‐8 Nishi‐Shinbashi, Minato‐ku Tokyo 105‐8461 Japan
| | - Rei Koizumi
- Department of Biochemistry The Jikei University School of Medicine 3‐25‐8 Nishi‐Shinbashi, Minato‐ku Tokyo 105‐8461 Japan
| | - Saya Motohashi
- Department of Biochemistry The Jikei University School of Medicine 3‐25‐8 Nishi‐Shinbashi, Minato‐ku Tokyo 105‐8461 Japan
| | - Yuya Shimoyama
- Department of Biochemistry The Jikei University School of Medicine 3‐25‐8 Nishi‐Shinbashi, Minato‐ku Tokyo 105‐8461 Japan
| | - Yoshito Hannya
- Department of Biochemistry The Jikei University School of Medicine 3‐25‐8 Nishi‐Shinbashi, Minato‐ku Tokyo 105‐8461 Japan
| | - Saishu Yoshida
- Department of Biochemistry The Jikei University School of Medicine 3‐25‐8 Nishi‐Shinbashi, Minato‐ku Tokyo 105‐8461 Japan
| | - Tsunekazu Oikawa
- Division of Gastroenterology and Hepatology Department of Internal Medicine The Jikei University School of Medicine 3‐25‐8 Nishi‐Shinbashi, Minato‐ku Tokyo 105‐8461 Japan
| | - Masayuki Shimoda
- Department of Pathology The Jikei University School of Medicine 3‐25‐8 Nishi‐Shinbashi, Minato‐ku Tokyo 105‐8461 Japan
| | - Kiyotsugu Yoshida
- Department of Biochemistry The Jikei University School of Medicine 3‐25‐8 Nishi‐Shinbashi, Minato‐ku Tokyo 105‐8461 Japan
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9
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Pradhan S, Gao R, Bush K, Zhang N, Wairkar YP, Sarkar PS. Polyglutamine Expansion in Huntingtin and Mechanism of DNA Damage Repair Defects in Huntington’s Disease. Front Cell Neurosci 2022; 16:837576. [PMID: 35444517 PMCID: PMC9013776 DOI: 10.3389/fncel.2022.837576] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 02/07/2022] [Indexed: 12/27/2022] Open
Abstract
Emerging evidence suggests that DNA repair deficiency and genome instability may be the impending signs of many neurological diseases. Genome-wide association (GWAS) studies have established a strong correlation between genes that play a role in DNA damage repair and many neurodegenerative diseases, including Huntington’s disease (HD), and several other trinucleotides repeat expansion-related hereditary ataxias. Recently, many reports have documented a significant role played by the DNA repair processes in aging and in modifying many neurodegenerative diseases, early during their progression. Studies from our lab and others have now begun to understand the mechanisms that cause defective DNA repair in HD and surprisingly, many proteins that have a strong link to known neurodegenerative diseases seem to be important players in these cellular pathways. Mutations in huntingtin (HTT) gene that lead to polyglutamine repeat expansion at the N-terminal of HTT protein has been shown to disrupt transcription-coupled DNA repair process, a specialized DNA repair process associated with transcription. Due to the recent progress made in understanding the mechanisms of DNA repair in relation to HD, in this review, we will mainly focus on the mechanisms by which the wild-type huntingtin (HTT) protein helps in DNA repair during transcription, and the how polyglutamine expansions in HTT impedes this process in HD. Further studies that identify new players in DNA repair will help in our understanding of this process in neurons. Furthermore, it should help us understand how various DNA repair mechanism(s) coordinate to maintain the normal physiology of neurons, and provide insights for the development of novel drugs at prodromal stages of these neurodegenerative diseases.
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Affiliation(s)
- Subrata Pradhan
- Department of Neurology, University of Texas Medical Branch, Galveston, TX, United States
| | - Rui Gao
- Department of Neurology, University of Texas Medical Branch, Galveston, TX, United States
| | - Keegan Bush
- Department of Neuroscience, Cell Biology and Anatomy, University of Texas Medical Branch, Galveston, TX, United States
| | - Nan Zhang
- Department of Neurology, Houston Methodist Research Institute, Houston, TX, United States
| | - Yogesh P. Wairkar
- Department of Neurology, University of Texas Medical Branch, Galveston, TX, United States
- Department of Neuroscience, Cell Biology and Anatomy, University of Texas Medical Branch, Galveston, TX, United States
| | - Partha S. Sarkar
- Department of Neurology, University of Texas Medical Branch, Galveston, TX, United States
- Department of Neuroscience, Cell Biology and Anatomy, University of Texas Medical Branch, Galveston, TX, United States
- *Correspondence: Partha S. Sarkar,
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Liu Z, Dong L, Zheng Z, Liu S, Gong S, Meng L, Xin Y, Jiang X. Mechanism, Prevention, and Treatment of Radiation-Induced Salivary Gland Injury Related to Oxidative Stress. Antioxidants (Basel) 2021; 10:antiox10111666. [PMID: 34829539 PMCID: PMC8614677 DOI: 10.3390/antiox10111666] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/14/2021] [Accepted: 10/19/2021] [Indexed: 12/24/2022] Open
Abstract
Radiation therapy is a common treatment for head and neck cancers. However, because of the presence of nerve structures (brain stem, spinal cord, and brachial plexus), salivary glands (SGs), mucous membranes, and swallowing muscles in the head and neck regions, radiotherapy inevitably causes damage to these normal tissues. Among them, SG injury is a serious adverse event, and its clinical manifestations include changes in taste, difficulty chewing and swallowing, oral infections, and dental caries. These clinical symptoms seriously reduce a patient’s quality of life. Therefore, it is important to clarify the mechanism of SG injury caused by radiotherapy. Although the mechanism of radiation-induced SG injury has not yet been determined, recent studies have shown that the mechanisms of calcium signaling, microvascular injury, cellular senescence, and apoptosis are closely related to oxidative stress. In this article, we review the mechanism by which radiotherapy causes oxidative stress and damages the SGs. In addition, we discuss effective methods to prevent and treat radiation-induced SG damage.
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Affiliation(s)
- Zijing Liu
- Jilin Provincial Key Laboratory of Radiation Oncology & Therapy, The First Hospital of Jilin University, Changchun 130021, China; (Z.L.); (L.D.); (Z.Z.); (S.L.); (S.G.)
- Department of Radiation Oncology, The First Hospital of Jilin University, Changchun 130021, China
- NHC Key Laboratory of Radiobiology, School of Public Health, Jilin University, Changchun 130021, China
| | - Lihua Dong
- Jilin Provincial Key Laboratory of Radiation Oncology & Therapy, The First Hospital of Jilin University, Changchun 130021, China; (Z.L.); (L.D.); (Z.Z.); (S.L.); (S.G.)
- Department of Radiation Oncology, The First Hospital of Jilin University, Changchun 130021, China
- NHC Key Laboratory of Radiobiology, School of Public Health, Jilin University, Changchun 130021, China
| | - Zhuangzhuang Zheng
- Jilin Provincial Key Laboratory of Radiation Oncology & Therapy, The First Hospital of Jilin University, Changchun 130021, China; (Z.L.); (L.D.); (Z.Z.); (S.L.); (S.G.)
- Department of Radiation Oncology, The First Hospital of Jilin University, Changchun 130021, China
- NHC Key Laboratory of Radiobiology, School of Public Health, Jilin University, Changchun 130021, China
| | - Shiyu Liu
- Jilin Provincial Key Laboratory of Radiation Oncology & Therapy, The First Hospital of Jilin University, Changchun 130021, China; (Z.L.); (L.D.); (Z.Z.); (S.L.); (S.G.)
- Department of Radiation Oncology, The First Hospital of Jilin University, Changchun 130021, China
- NHC Key Laboratory of Radiobiology, School of Public Health, Jilin University, Changchun 130021, China
| | - Shouliang Gong
- Jilin Provincial Key Laboratory of Radiation Oncology & Therapy, The First Hospital of Jilin University, Changchun 130021, China; (Z.L.); (L.D.); (Z.Z.); (S.L.); (S.G.)
- Department of Radiation Oncology, The First Hospital of Jilin University, Changchun 130021, China
- NHC Key Laboratory of Radiobiology, School of Public Health, Jilin University, Changchun 130021, China
| | - Lingbin Meng
- Department of Hematology and Medical Oncology, Moffitt Cancer Center, Tampa, FL 33612, USA;
| | - Ying Xin
- Key Laboratory of Pathobiology, Ministry of Education, Jilin University, Changchun 130021, China;
| | - Xin Jiang
- Jilin Provincial Key Laboratory of Radiation Oncology & Therapy, The First Hospital of Jilin University, Changchun 130021, China; (Z.L.); (L.D.); (Z.Z.); (S.L.); (S.G.)
- Department of Radiation Oncology, The First Hospital of Jilin University, Changchun 130021, China
- NHC Key Laboratory of Radiobiology, School of Public Health, Jilin University, Changchun 130021, China
- Correspondence: ; Tel.: +86-158-0430-2750
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11
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Affandi T, Ohm AM, Gaillard D, Haas A, Reyland ME. Tyrosine kinase inhibitors protect the salivary gland from radiation damage by increasing DNA double-strand break repair. J Biol Chem 2021; 296:100401. [PMID: 33571522 DOI: 10.1016/j.jbc.2021.100401] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/01/2021] [Accepted: 02/05/2021] [Indexed: 11/23/2022] Open
Abstract
We have previously shown that the tyrosine kinase inhibitors (TKIs) dasatinib and imatinib can protect salivary glands from irradiation (IR) damage without impacting tumor therapy. However, how they induce this protection is unknown. Here we show that TKIs mediate radioprotection by increasing the repair of DNA double-stranded breaks. DNA repair in IR-treated parotid cells, but not oral cancer cells, occurs more rapidly following pretreatment with imatinib or dasatinib and is accompanied by faster formation of DNA damage-induced foci. Similar results were observed in the parotid glands of mice pretreated with imatinib prior to IR, suggesting that TKIs "prime" cells for DNA repair. Mechanistically, we observed that TKIs increased IR-induced activation of DNA-PK, but not ATM. Pretreatment of parotid cells with the DNA-PK inhibitor NU7441 reversed the increase in DNA repair induced by TKIs. Reporter assays specific for homologous recombination (HR) or nonhomologous end joining (NHEJ) verified regulatation of both DNA repair pathways by imatinib. Moreover, TKIs also increased basal and IR-induced expression of genes associated with NHEJ (DNA ligase 4, Artemis, XLF) and HR (Rad50, Rad51 and BRCA1); depletion of DNA ligase 4 or BRCA1 reversed the increase in DNA repair mediated by TKIs. In addition, TKIs increased activation of the ERK survival pathway in parotid cells, and ERK was required for the increased survival of TKI-treated cells. Our studies demonstrate a dual mechanism by which TKIs provide radioprotection of the salivary gland tissues and support exploration of TKIs clinically in head and neck cancer patients undergoing IR therapy.
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12
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Yamada K, Oikawa T, Kizawa R, Motohashi S, Yoshida S, Kumamoto T, Saeki C, Nakagawa C, Shimoyama Y, Aoki K, Tachibana T, Saruta M, Ono M, Yoshida K. Unconventional Secretion of PKCδ Exerts Tumorigenic Function via Stimulation of ERK1/2 Signaling in Liver Cancer. Cancer Res 2020; 81:414-425. [PMID: 33318039 DOI: 10.1158/0008-5472.can-20-2009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 10/02/2020] [Accepted: 11/18/2020] [Indexed: 11/16/2022]
Abstract
Expression of human protein kinase C delta (PKCδ) protein has been linked to many types of cancers. PKCδ is known to be a multifunctional PKC family member and has been rigorously studied as an intracellular signaling molecule. Here we show that PKCδ is a secretory protein that regulates cell growth of liver cancer. Full-length PKCδ was secreted to the extracellular space in living liver cancer cells under normal cell culture conditions and in xenograft mouse models. Patients with liver cancer showed higher levels of serum PKCδ than patients with chronic hepatitis or liver cirrhosis or healthy individuals. In liver cancer cells, PKCδ secretion was executed in an endoplasmic reticulum (ER)-Golgi-independent manner, and the inactivation status of cytosolic PKCδ was required for its secretion. Furthermore, colocalization studies showed that extracellular PKCδ was anchored on the cell surface of liver cancer cells via association with glypican 3, a liver cancer-related heparan sulfate proteoglycan. Addition of exogenous PKCδ activated IGF-1 receptor (IGF1R) activation and subsequently enhanced activation of ERK1/2, which led to accelerated cell growth in liver cancer cells. Conversely, treatment with anti-PKCδ antibody attenuated activation of both IGF1R and ERK1/2 and reduced cell proliferation and spheroid formation of liver cancer cells and tumor growth in xenograft mouse models. This study demonstrates the presence of PKCδ at the extracellular space and the function of PKCδ as a growth factor and provides a rationale for the extracellular PKCδ-targeting therapy of liver cancer. SIGNIFICANCE: PKCδ secretion from liver cancer cells behaves as a humoral growth factor that contributes to cell growth via activation of proliferative signaling molecules, which may be potential diagnostic or therapeutic targets.
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Affiliation(s)
- Kohji Yamada
- Department of Biochemistry, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Tsunekazu Oikawa
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Ryusuke Kizawa
- Department of Biochemistry, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Saya Motohashi
- Department of Biochemistry, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Saishu Yoshida
- Department of Biochemistry, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Tomotaka Kumamoto
- Department of Biochemistry, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Chisato Saeki
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Chika Nakagawa
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Yuya Shimoyama
- Department of Biochemistry, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Katsuhiko Aoki
- Department of Biochemistry, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Toshiaki Tachibana
- Core Research Facilities for Basic Science, Research Center for Medical Sciences, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Masayuki Saruta
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Masaya Ono
- Department of Clinical Proteomics, National Cancer Center Research Institute, Chuo-ku, Tokyo, Japan
| | - Kiyotsugu Yoshida
- Department of Biochemistry, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan.
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13
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Speidel JT, Affandi T, Jones DNM, Ferrara SE, Reyland ME. Functional proteomic analysis reveals roles for PKCδ in regulation of cell survival and cell death: Implications for cancer pathogenesis and therapy. Adv Biol Regul 2020; 78:100757. [PMID: 33045516 PMCID: PMC8294469 DOI: 10.1016/j.jbior.2020.100757] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 09/18/2020] [Accepted: 09/21/2020] [Indexed: 12/18/2022]
Abstract
Protein Kinase C-δ (PKCδ), regulates a broad group of biological functions and disease processes, including well-defined roles in immune function, cell survival and apoptosis. PKCδ primarily regulates apoptosis in normal tissues and non-transformed cells, and genetic disruption of the PRKCD gene in mice is protective in many diseases and tissue damage models. However pro-survival/pro-proliferative functions have also been described in some transformed cells and in mouse models of cancer. Recent evidence suggests that the contribution of PKCδ to specific cancers may depend in part on the oncogenic context of the tumor, consistent with its paradoxical role in cell survival and cell death. Here we will discuss what is currently known about biological functions of PKCδ and potential paradigms for PKCδ function in cancer. To further understand mechanisms of regulation by PKCδ, and to gain insight into the plasticity of PKCδ signaling, we have used functional proteomics to identify pathways that are dependent on PKCδ. Understanding how these distinct functions of PKCδ are regulated will be critical for the logical design of therapeutics to target this pathway.
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Affiliation(s)
- Jordan T Speidel
- Department of Craniofacial Biology, School of Dental Medicine, USA
| | - Trisiani Affandi
- Department of Craniofacial Biology, School of Dental Medicine, USA
| | | | - Sarah E Ferrara
- University of Colorado Comprehensive Cancer Center, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Mary E Reyland
- Department of Craniofacial Biology, School of Dental Medicine, USA.
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14
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Tsai JY, Rédei D, Hohmann J, Wu CC. 12-Deoxyphorbol Esters Induce Growth Arrest and Apoptosis in Human Lung Cancer A549 Cells Via Activation of PKC-δ/PKD/ERK Signaling Pathway. Int J Mol Sci 2020; 21:E7579. [PMID: 33066446 DOI: 10.3390/ijms21207579] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/09/2020] [Accepted: 10/13/2020] [Indexed: 12/16/2022] Open
Abstract
Prostratin, a non-tumor promoting 12-deoxyphorbol ester, has been reported as a protein kinase C (PKC) activator and is shown to have anti-proliferative activity in certain cancer cell types. Here we show that GRC-2, a prostratin analogue isolated from Euphorbia grandicornis, is ten-fold more potent than prostratin for inhibiting the growth of human non-small cell lung cancer (NSCLC) A549 cells. Flow cytometry assay revealed that GRC-2 and prostratin inhibited cell cycle progression at the G2/M phase and induced apoptosis. The cytotoxic effect of GRC-2 and prostratin was accompanied by activation and nuclear translocation of PKC-δ and PKD as well as hyperactivation of extracellular signal-related kinase (ERK). Knockdown of either PKC-δ, PKD or ERK significantly protected A549 cancer cells from GRC-2- and prostratin-induced growth arrest as well as apoptosis. Taken together, our results have shown that prostratin and a more potent analogue GRC-2 reduce cell viability in NSCLC A549 cells, at least in part, through activation of the PKC-δ/PKD/ERK pathway, suggesting the potential of prostratin and GRC-2 as anticancer agents.
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15
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Jego G, Hermetet F, Girodon F, Garrido C. Chaperoning STAT3/5 by Heat Shock Proteins: Interest of Their Targeting in Cancer Therapy. Cancers (Basel) 2019; 12:cancers12010021. [PMID: 31861612 PMCID: PMC7017265 DOI: 10.3390/cancers12010021] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 12/05/2019] [Accepted: 12/13/2019] [Indexed: 01/16/2023] Open
Abstract
While cells from multicellular organisms are dependent upon exogenous signals for their survival, growth, and proliferation, commitment to a specific cell fate requires the correct folding and maturation of proteins, as well as the degradation of misfolded or aggregated proteins within the cell. This general control of protein quality involves the expression and the activity of molecular chaperones such as heat shock proteins (HSPs). HSPs, through their interaction with the STAT3/STAT5 transcription factor pathway, can be crucial both for the tumorigenic properties of cancer cells (cell proliferation, survival) and for the microenvironmental immune cell compartment (differentiation, activation, cytokine secretion) that contributes to immunosuppression, which, in turn, potentially promotes tumor progression. Understanding the contribution of chaperones such as HSP27, HSP70, HSP90, and HSP110 to the STAT3/5 signaling pathway has raised the possibility of targeting such HSPs to specifically restrain STAT3/5 oncogenic functions. In this review, we present how HSPs control STAT3 and STAT5 activation, and vice versa, how the STAT signaling pathways modulate HSP expression. We also discuss whether targeting HSPs is a valid therapeutic option and which HSP would be the best candidate for such a strategy.
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Affiliation(s)
- Gaëtan Jego
- INSERM, LNC UMR1231, team HSP-Pathies, University of Bourgogne Franche-Comté, F-21000 Dijon, France; (F.H.); (F.G.)
- UFR des Sciences de Santé, University of Burgundy and Franche-Comté, F-21000 Dijon, France
- Correspondence: (C.G.); (G.J.); Tel.: +33-3-8039-3345 (G.J.); Fax: +33-3-8039-3434 (C.G. & G.J.)
| | - François Hermetet
- INSERM, LNC UMR1231, team HSP-Pathies, University of Bourgogne Franche-Comté, F-21000 Dijon, France; (F.H.); (F.G.)
- UFR des Sciences de Santé, University of Burgundy and Franche-Comté, F-21000 Dijon, France
| | - François Girodon
- INSERM, LNC UMR1231, team HSP-Pathies, University of Bourgogne Franche-Comté, F-21000 Dijon, France; (F.H.); (F.G.)
- UFR des Sciences de Santé, University of Burgundy and Franche-Comté, F-21000 Dijon, France
- Haematology laboratory, Dijon University Hospital, F-21000 Dijon, France
| | - Carmen Garrido
- INSERM, LNC UMR1231, team HSP-Pathies, University of Bourgogne Franche-Comté, F-21000 Dijon, France; (F.H.); (F.G.)
- UFR des Sciences de Santé, University of Burgundy and Franche-Comté, F-21000 Dijon, France
- Centre Georges François Leclerc, 21000 Dijon, France
- Correspondence: (C.G.); (G.J.); Tel.: +33-3-8039-3345 (G.J.); Fax: +33-3-8039-3434 (C.G. & G.J.)
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16
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Liebl MC, Hofmann TG. Cell Fate Regulation upon DNA Damage: p53 Serine 46 Kinases Pave the Cell Death Road. Bioessays 2019; 41:e1900127. [PMID: 31621101 DOI: 10.1002/bies.201900127] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 09/16/2019] [Indexed: 12/20/2022]
Abstract
Mild and massive DNA damage are differentially integrated into the cellular signaling networks and, in consequence, provoke different cell fate decisions. After mild damage, the tumor suppressor p53 directs the cellular response to cell cycle arrest, DNA repair, and cell survival, whereas upon severe damage, p53 drives the cell death response. One posttranslational modification of p53, phosphorylation at Serine 46, selectively occurs after severe DNA damage and is envisioned as a marker of the cell death response. However, the molecular mechanism of action of the p53 Ser46 phospho-isomer, the molecular timing of this phosphorylation event, and its activating effects on apoptosis and ferroptosis still await exploration. In this essay, the current body of evidence on the molecular function of this deadly p53 mark, its evolutionary conservation, and the regulation of the key players of this response, the p53 Serine 46 kinases, are reviewed and dissected.
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Affiliation(s)
- Magdalena C Liebl
- Institute of Toxicology, University Medical Center of the Johannes Gutenberg, University Mainz, Obere Zahlbacher Str. 67, 55131, Mainz, Germany
| | - Thomas G Hofmann
- Institute of Toxicology, University Medical Center of the Johannes Gutenberg, University Mainz, Obere Zahlbacher Str. 67, 55131, Mainz, Germany
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17
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Ohm AM, Affandi T, Reyland ME. EGF receptor and PKCδ kinase activate DNA damage-induced pro-survival and pro-apoptotic signaling via biphasic activation of ERK and MSK1 kinases. J Biol Chem 2019; 294:4488-4497. [PMID: 30679314 DOI: 10.1074/jbc.ra118.006944] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 01/16/2019] [Indexed: 01/18/2023] Open
Abstract
DNA damage-mediated activation of extracellular signal-regulated kinase (ERK) can regulate both cell survival and cell death. We show here that ERK activation in this context is biphasic and that early and late activation events are mediated by distinct upstream signals that drive cell survival and apoptosis, respectively. We identified the nuclear kinase mitogen-sensitive kinase 1 (MSK1) as a downstream target of both early and late ERK activation. We also observed that activation of ERK→MSK1 up to 4 h after DNA damage depends on epidermal growth factor receptor (EGFR), as EGFR or mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK)/ERK inhibitors or short hairpin RNA-mediated MSK1 depletion enhanced cell death. This prosurvival response was partially mediated through enhanced DNA repair, as EGFR or MEK/ERK inhibitors delayed DNA damage resolution. In contrast, the second phase of ERK→MSK1 activation drove apoptosis and required protein kinase Cδ (PKCδ) but not EGFR. Genetic disruption of PKCδ reduced ERK activation in an in vivo irradiation model, as did short hairpin RNA-mediated depletion of PKCδ in vitro In both models, PKCδ inhibition preferentially suppressed late activation of ERK. We have shown previously that nuclear localization of PKCδ is necessary and sufficient for apoptosis. Here we identified a nuclear PKCδ→ERK→MSK1 signaling module that regulates apoptosis. We also show that expression of nuclear PKCδ activates ERK and MSK1, that ERK activation is required for MSK1 activation, and that both ERK and MSK1 activation are required for apoptosis. Our findings suggest that location-specific activation by distinct upstream regulators may enable distinct functional outputs from common signaling pathways.
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Affiliation(s)
- Angela M Ohm
- From the Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
| | - Trisiani Affandi
- From the Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
| | - Mary E Reyland
- From the Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
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18
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Liu Z, Khalil RA. Evolving mechanisms of vascular smooth muscle contraction highlight key targets in vascular disease. Biochem Pharmacol 2018; 153:91-122. [PMID: 29452094 PMCID: PMC5959760 DOI: 10.1016/j.bcp.2018.02.012] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 02/12/2018] [Indexed: 12/11/2022]
Abstract
Vascular smooth muscle (VSM) plays an important role in the regulation of vascular function. Identifying the mechanisms of VSM contraction has been a major research goal in order to determine the causes of vascular dysfunction and exaggerated vasoconstriction in vascular disease. Major discoveries over several decades have helped to better understand the mechanisms of VSM contraction. Ca2+ has been established as a major regulator of VSM contraction, and its sources, cytosolic levels, homeostatic mechanisms and subcellular distribution have been defined. Biochemical studies have also suggested that stimulation of Gq protein-coupled membrane receptors activates phospholipase C and promotes the hydrolysis of membrane phospholipids into inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG). IP3 stimulates initial Ca2+ release from the sarcoplasmic reticulum, and is buttressed by Ca2+ influx through voltage-dependent, receptor-operated, transient receptor potential and store-operated channels. In order to prevent large increases in cytosolic Ca2+ concentration ([Ca2+]c), Ca2+ removal mechanisms promote Ca2+ extrusion via the plasmalemmal Ca2+ pump and Na+/Ca2+ exchanger, and Ca2+ uptake by the sarcoplasmic reticulum and mitochondria, and the coordinated activities of these Ca2+ handling mechanisms help to create subplasmalemmal Ca2+ domains. Threshold increases in [Ca2+]c form a Ca2+-calmodulin complex, which activates myosin light chain (MLC) kinase, and causes MLC phosphorylation, actin-myosin interaction, and VSM contraction. Dissociations in the relationships between [Ca2+]c, MLC phosphorylation, and force have suggested additional Ca2+ sensitization mechanisms. DAG activates protein kinase C (PKC) isoforms, which directly or indirectly via mitogen-activated protein kinase phosphorylate the actin-binding proteins calponin and caldesmon and thereby enhance the myofilaments force sensitivity to Ca2+. PKC-mediated phosphorylation of PKC-potentiated phosphatase inhibitor protein-17 (CPI-17), and RhoA-mediated activation of Rho-kinase (ROCK) inhibit MLC phosphatase and in turn increase MLC phosphorylation and VSM contraction. Abnormalities in the Ca2+ handling mechanisms and PKC and ROCK activity have been associated with vascular dysfunction in multiple vascular disorders. Modulators of [Ca2+]c, PKC and ROCK activity could be useful in mitigating the increased vasoconstriction associated with vascular disease.
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Affiliation(s)
- Zhongwei Liu
- Vascular Surgery Research Laboratories, Division of Vascular and Endovascular Surgery, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA 02115, USA
| | - Raouf A Khalil
- Vascular Surgery Research Laboratories, Division of Vascular and Endovascular Surgery, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA 02115, USA.
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19
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Wie SM, Wellberg E, Karam SD, Reyland ME. Tyrosine Kinase Inhibitors Protect the Salivary Gland from Radiation Damage by Inhibiting Activation of Protein Kinase C-δ. Mol Cancer Ther 2017. [PMID: 28637715 DOI: 10.1158/1535-7163.mct-17-0267] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In patients undergoing irradiation (IR) therapy, injury to nontumor tissues can result in debilitating, and sometimes permanent, side effects. We have defined protein kinase C-δ (PKCδ) as a regulator of DNA damage-induced apoptosis and have shown that phosphorylation of PKCδ by c-Abl and c-Src activates its proapoptotic function. Here, we have explored the use of tyrosine kinase inhibitors (TKI) of c-Src and c-Abl to block activation of PKCδ for radioprotection of the salivary gland. Dasatinib, imatinib, and bosutinib all suppressed tyrosine phosphorylation of PKCδ and inhibited IR-induced apoptosis in vitro To determine whether TKIs can provide radioprotection of salivary gland function in vivo, mice were treated with TKIs and a single or fractionated doses of irradiation. Delivery of dasatinib or imatinib within 3 hours of a single or fractionated dose of irradiation resulted in >75% protection of salivary gland function at 60 days. Continuous dosing with dasatinib extended protection to at least 5 months and correlated with histologic evidence of salivary gland acinar cell regeneration. Pretreatment with TKIs had no impact on clonogenic survival of head and neck squamous cell carcinoma (HNSCC) cells, and in mice harboring HNSCC cell-derived xenografts, combining dasatinib or imatinib with fractionated irradiation did not enhance tumor growth. Our studies indicate that TKIs may be useful clinically to protect nontumor tissue in HNC patients undergoing radiotherapy, without negatively impacting cancer treatment. Mol Cancer Ther; 16(9); 1989-98. ©2017 AACR.
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Affiliation(s)
- Sten M Wie
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado, Anschutz Medical Campus, Aurora, Colorado
| | - Elizabeth Wellberg
- Department of Pathology, School of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, Colorado
| | - Sana D Karam
- Department of IR Oncology, School of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, Colorado
| | - Mary E Reyland
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado, Anschutz Medical Campus, Aurora, Colorado.
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20
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Isakov N. Protein kinase C (PKC) isoforms in cancer, tumor promotion and tumor suppression. Semin Cancer Biol 2017; 48:36-52. [PMID: 28571764 DOI: 10.1016/j.semcancer.2017.04.012] [Citation(s) in RCA: 157] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 03/22/2017] [Accepted: 04/25/2017] [Indexed: 12/27/2022]
Abstract
The AGC family of serine/threonine kinases (PKA, PKG, PKC) includes more than 60 members that are critical regulators of numerous cellular functions, including cell cycle and differentiation, morphogenesis, and cell survival and death. Mutation and/or dysregulation of AGC kinases can lead to malignant cell transformation and contribute to the pathogenesis of many human diseases. Members of one subgroup of AGC kinases, the protein kinase C (PKC), have been singled out as critical players in carcinogenesis, following their identification as the intracellular receptors of phorbol esters, which exhibit tumor-promoting activities. This observation attracted the attention of researchers worldwide and led to intense investigations on the role of PKC in cell transformation and the potential use of PKC as therapeutic drug targets in cancer diseases. Studies demonstrated that many cancers had altered expression and/or mutation of specific PKC genes. However, the causal relationships between the changes in PKC gene expression and/or mutation and the direct cause of cancer remain elusive. Independent studies in normal cells demonstrated that activation of PKC is essential for the induction of cell activation and proliferation, differentiation, motility, and survival. Based on these observations and the general assumption that PKC isoforms play a positive role in cell transformation and/or cancer progression, many PKC inhibitors have entered clinical trials but the numerous attempts to target PKC in cancer has so far yielded only very limited success. More recent studies demonstrated that PKC function as tumor suppressors, and suggested that future clinical efforts should focus on restoring, rather than inhibiting, PKC activity. The present manuscript provides some historical perspectives on the tumor promoting function of PKC, reviewing some of the observations linking PKC to cancer progression, and discusses the role of PKC in the pathogenesis of cancer diseases and its potential usage as a therapeutic target.
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Affiliation(s)
- Noah Isakov
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences and the Cancer Research Center, Ben Gurion University of the Negev, P.O.B. 653, Beer Sheva 84105, Israel.
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Ohm AM, Tan AC, Heasley LE, Reyland ME. Co-dependency of PKCδ and K-Ras: inverse association with cytotoxic drug sensitivity in KRAS mutant lung cancer. Oncogene 2017; 36:4370-8. [PMID: 28368426 DOI: 10.1038/onc.2017.27] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 12/15/2016] [Accepted: 01/11/2017] [Indexed: 12/29/2022]
Abstract
Recent studies suggest that the presence of a KRAS mutation may be insufficient for defining a clinically homogenous molecular group, as many KRAS mutant tumors lose reliance on K-Ras for survival. Identifying pathways that support K-Ras dependency may define clinically relevant KRAS sub-groups and lead to the identification of new drug targets. We have analyzed a panel of 17 KRAS mutant lung cancer cell lines classified as K-Ras dependent or independent, for co-dependency on PKCδ. We show that functional dependency on K-Ras and PKCδ co-segregate, and that dependency correlates with a more epithelial-like phenotype. Furthermore, we show that the pro-apoptotic and pro-tumorigenic functions of PKCδ also segregate based on K-Ras dependency, as K-Ras independent cells are more sensitive to topoisomerase inhibitors, and depletion of PKCδ in this sub-group suppresses apoptosis through increased activation of ERK. In contrast, K-Ras dependent lung cancer cells are largely insensitive to topoisomerase inhibitors, and depletion of PKCδ can increase apoptosis and decrease activation of ERK in this sub-group. We have previously shown that nuclear translocation of PKCδ is necessary and sufficient for pro-apoptotic signaling. Our current studies show that K-Ras dependent cells are refractive to PKCδ driven apoptosis. Analysis of this sub-group showed increased PKCδ expression and an increase in the nuclear:cytoplasmic ratio of PKCδ. In addition, targeting PKCδ to the nucleus induces apoptosis in K-Ras independent, but not K-Ras dependent NSCLC cells. Our studies provide tools for identification of the subset of patients with KRAS mutant tumors most amenable to targeting of the K-Ras pathway, and identify PKCδ as a potential target in this tumor population. These sub-groups are likely to be of clinical relevance, as high PKCδ expression correlates with increased overall survival and a more epithelial tumor phenotype in patients with KRAS mutant lung adenocarcinomas.
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Misuth M, Joniova J, Horvath D, Dzurova L, Nichtova Z, Novotova M, Miskovsky P, Stroffekova K, Huntosova V. The flashlights on a distinct role of protein kinase C δ: Phosphorylation of regulatory and catalytic domain upon oxidative stress in glioma cells. Cell Signal 2017; 34:11-22. [PMID: 28237688 DOI: 10.1016/j.cellsig.2017.02.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 02/07/2017] [Accepted: 02/20/2017] [Indexed: 01/02/2023]
Abstract
Glioblastoma multiforme are considered to be aggressive high-grade tumors with poor prognosis for patient survival. Photodynamic therapy is one of the adjuvant therapies which has been used for glioblastoma multiforme during last decade. Hypericin, a photosensitizer, can be employed in this treatment. We have studied the effect of hypericin on PKCδ phosphorylation in U87 MG cells before and after light application. Hypericin increased PKCδ phosphorylation at tyrosine 155 in the regulatory domain and serine 645 in the catalytic domain. However, use of the light resulted in apoptosis, decreased phosphorylation of tyrosine 155 and enhanced serine 645. The PKCδ localization and phosphorylation of regulatory and catalytic domains were shown to play a distinct role in the anti-apoptotic response of glioma cells. We hypothesized that PKCδ phosphorylated at the regulatory domain is primarily present in the cytoplasm and in mitochondria before irradiation, and it may participate in Bcl-2 phosphorylation. After hypericin and light application, PKCδ phosphorylated at a regulatory domain which is in the nucleus. In contrast, PKCδ phosphorylated at the catalytic domain may be mostly active in the nucleus before irradiation, but active in the cytoplasm after the irradiation. In summary, light-induced oxidative stress significantly regulates PKCδ pro-survival and pro-apoptotic activity in glioma cells by its phosphorylation at serine 645 and tyrosine 155.
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Affiliation(s)
- Matus Misuth
- Department of Biophysics, Faculty of Sciences, P. J. Safarik University in Kosice, Jesenna 5, 041 54, Kosice, Slovakia
| | - Jaroslava Joniova
- Department of Biophysics, Faculty of Sciences, P. J. Safarik University in Kosice, Jesenna 5, 041 54, Kosice, Slovakia
| | - Denis Horvath
- Center for Interdisciplinary Biosciences, Faculty of Sciences, P.J. Safarik University in Kosice, Jesenna 5, 041 54, Kosice, Slovakia
| | - Lenka Dzurova
- Department of Biophysics, Faculty of Sciences, P. J. Safarik University in Kosice, Jesenna 5, 041 54, Kosice, Slovakia
| | - Zuzana Nichtova
- Department of Muscle Cell Research, Institute of Molecular Physiology and Genetics, Centre of Biosciences, Slovak Academy of Science, Bratislava, Slovakia
| | - Marta Novotova
- Department of Muscle Cell Research, Institute of Molecular Physiology and Genetics, Centre of Biosciences, Slovak Academy of Science, Bratislava, Slovakia
| | - Pavol Miskovsky
- Center for Interdisciplinary Biosciences, Faculty of Sciences, P.J. Safarik University in Kosice, Jesenna 5, 041 54, Kosice, Slovakia; SAFTRA Photonics Ltd., Jesenna 5, 041 54, Kosice, Slovakia
| | - Katarina Stroffekova
- Department of Biophysics, Faculty of Sciences, P. J. Safarik University in Kosice, Jesenna 5, 041 54, Kosice, Slovakia; Center for Interdisciplinary Biosciences, Faculty of Sciences, P.J. Safarik University in Kosice, Jesenna 5, 041 54, Kosice, Slovakia
| | - Veronika Huntosova
- Center for Interdisciplinary Biosciences, Faculty of Sciences, P.J. Safarik University in Kosice, Jesenna 5, 041 54, Kosice, Slovakia.
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Ringvold HC, Khalil RA. Protein Kinase C as Regulator of Vascular Smooth Muscle Function and Potential Target in Vascular Disorders. Adv Pharmacol 2017; 78:203-301. [PMID: 28212798 DOI: 10.1016/bs.apha.2016.06.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Vascular smooth muscle (VSM) plays an important role in maintaining vascular tone. In addition to Ca2+-dependent myosin light chain (MLC) phosphorylation, protein kinase C (PKC) is a major regulator of VSM function. PKC is a family of conventional Ca2+-dependent α, β, and γ, novel Ca2+-independent δ, ɛ, θ, and η, and atypical ξ, and ι/λ isoforms. Inactive PKC is mainly cytosolic, and upon activation it undergoes phosphorylation, maturation, and translocation to the surface membrane, the nucleus, endoplasmic reticulum, and other cell organelles; a process facilitated by scaffold proteins such as RACKs. Activated PKC phosphorylates different substrates including ion channels, pumps, and nuclear proteins. PKC also phosphorylates CPI-17 leading to inhibition of MLC phosphatase, increased MLC phosphorylation, and enhanced VSM contraction. PKC could also initiate a cascade of protein kinases leading to phosphorylation of the actin-binding proteins calponin and caldesmon, increased actin-myosin interaction, and VSM contraction. Increased PKC activity has been associated with vascular disorders including ischemia-reperfusion injury, coronary artery disease, hypertension, and diabetic vasculopathy. PKC inhibitors could test the role of PKC in different systems and could reduce PKC hyperactivity in vascular disorders. First-generation PKC inhibitors such as staurosporine and chelerythrine are not very specific. Isoform-specific PKC inhibitors such as ruboxistaurin have been tested in clinical trials. Target delivery of PKC pseudosubstrate inhibitory peptides and PKC siRNA may be useful in localized vascular disease. Further studies of PKC and its role in VSM should help design isoform-specific PKC modulators that are experimentally potent and clinically safe to target PKC in vascular disease.
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Holmgren C, Cornmark L, Lønne GK, Masoumi KC, Larsson C. Molecular characterization of protein kinase C delta (PKCδ)-Smac interactions. BMC Biochem 2016; 17:11. [PMID: 27216037 PMCID: PMC4877760 DOI: 10.1186/s12858-016-0065-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 05/17/2016] [Indexed: 12/12/2022]
Abstract
Background Protein kinase C δ (PKCδ) is known to be an important regulator of apoptosis, having mainly pro- but also anti-apoptotic effects depending on context. In a previous study, we found that PKCδ interacts with the pro-apoptotic protein Smac. Smac facilitates apoptosis by suppressing inhibitor of apoptosis proteins (IAPs). We previously established that the PKCδ-Smac complex dissociates during induction of apoptosis indicating a functional importance. Because the knowledge on the molecular determinants of the interaction is limited, we aimed at characterizing the interactions between PKCδ and Smac. Results We found that PKCδ binds directly to Smac through its regulatory domain. The interaction is enhanced by the PKC activator TPA and seems to be independent of PKCδ catalytic activity since the PKC kinase inhibitor GF109203X did not inhibit the interaction. In addition, we found that C1 and C2 domains from several PKC isoforms have Smac-binding capacity. Conclusions Our data demonstrate that the Smac-PKCδ interaction is direct and that it is facilitated by an open conformation of PKCδ. The binding is mediated via the PKCδ regulatory domain and both the C1 and C2 domains have Smac-binding capacity. With this study we thereby provide molecular information on an interaction between two apoptosis-regulating proteins.
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Affiliation(s)
- Christian Holmgren
- Lund University, Translational Cancer Research, Medicon Village, Building 404:C3, SE-22363, Lund, Sweden
| | - Louise Cornmark
- Lund University, Translational Cancer Research, Medicon Village, Building 404:C3, SE-22363, Lund, Sweden
| | - Gry Kalstad Lønne
- Lund University, Translational Cancer Research, Medicon Village, Building 404:C3, SE-22363, Lund, Sweden
| | | | - Christer Larsson
- Lund University, Translational Cancer Research, Medicon Village, Building 404:C3, SE-22363, Lund, Sweden.
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Abstract
The serine-threonine protein kinase, protein kinase C-δ (PKCδ), is emerging as a bi-functional regulator of cell death and proliferation. Studies in PKCδ-/- mice have confirmed a pro-apoptotic role for this kinase in response to DNA damage and a tumor promoter role in some oncogenic contexts. In non-transformed cells, inhibition of PKCδ suppresses the release of cytochrome c and caspase activation, indicating a function upstream of apoptotic pathways. Data from PKCδ-/- mice demonstrate a role for PKCδ in the execution of DNA damage-induced and physiologic apoptosis. This has led to the important finding that inhibitors of PKCδ can be used therapeutically to reduce irradiation and chemotherapy-induced toxicity. By contrast, PKCδ is a tumor promoter in mouse models of mammary gland and lung cancer, and increased PKCδ expression is a negative prognostic indicator in Her2+ and other subtypes of human breast cancer. Understanding how these distinct functions of PKCδ are regulated is critical for the design of therapeutics to target this pathway. This review will discuss what is currently known about biological roles of PKCδ and prospects for targeting PKCδ in human disease.
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Affiliation(s)
- Mary E Reyland
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.
| | - David N M Jones
- Department of Pharmacology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
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Jacobsen AV, Lowes KN, Tanzer MC, Lucet IS, Hildebrand JM, Petrie EJ, van Delft MF, Liu Z, Conos SA, Zhang JG, Huang DC, Silke J, Lessene G, Murphy JM. HSP90 activity is required for MLKL oligomerisation and membrane translocation and the induction of necroptotic cell death. Cell Death Dis 2016; 7:e2051. [PMID: 26775703 DOI: 10.1038/cddis.2015.386] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 11/30/2015] [Accepted: 12/02/2015] [Indexed: 01/02/2023]
Abstract
Necroptosis is a caspase-independent form of regulated cell death that has been implicated in the development of a range of inflammatory, autoimmune and neurodegenerative diseases. The pseudokinase, Mixed Lineage Kinase Domain-Like (MLKL), is the most terminal known obligatory effector in the necroptosis pathway, and is activated following phosphorylation by Receptor Interacting Protein Kinase-3 (RIPK3). Activated MLKL translocates to membranes, leading to membrane destabilisation and subsequent cell death. However, the molecular interactions governing the processes downstream of RIPK3 activation remain poorly defined. Using a phenotypic screen, we identified seven heat-shock protein 90 (HSP90) inhibitors that inhibited necroptosis in both wild-type fibroblasts and fibroblasts expressing an activated mutant of MLKL. We observed a modest reduction in MLKL protein levels in human and murine cells following HSP90 inhibition, which was only apparent after 15 h of treatment. The delayed reduction in MLKL protein abundance was unlikely to completely account for defective necroptosis, and, consistent with this, we also found inhibition of HSP90 blocked membrane translocation of activated MLKL. Together, these findings implicate HSP90 as a modulator of necroptosis at the level of MLKL, a function that complements HSP90's previously demonstrated modulation of the upstream necroptosis effector kinases, RIPK1 and RIPK3.
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Lim PS, Sutton CR, Rao S. Protein kinase C in the immune system: from signalling to chromatin regulation. Immunology 2015; 146:508-22. [PMID: 26194700 DOI: 10.1111/imm.12510] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 06/29/2015] [Accepted: 07/15/2015] [Indexed: 12/12/2022] Open
Abstract
Protein kinase C (PKC) form a key family of enzymes involved in signalling pathways that specifically phosphorylates substrates at serine/threonine residues. Phosphorylation by PKC is important in regulating a variety of cellular events such as cell proliferation and the regulation of gene expression. In the immune system, PKCs are involved in regulating signal transduction pathways important for both innate and adaptive immunity, ultimately resulting in the expression of key immune genes. PKCs act as mediators during immune cell signalling through the immunological synapse. PKCs are traditionally known to be cytoplasmic signal transducers and are well embedded in the signalling pathways of cells to mediate the cells' response to a stimulus from the plasma membrane to the nucleus. PKCs are also found to transduce signals within the nucleus, a process that is distinct from the cytoplasmic signalling pathway. There is now growing evidence suggesting that PKC can directly regulate gene expression programmes through a non-traditional role as nuclear kinases. In this review, we will focus on the role of PKCs as key cytoplasmic signal transducers in immune cell signalling, as well as its role in nuclear signal transduction. We will also highlight recent evidence for its newly discovered regulatory role in the nucleus as a chromatin-associated kinase.
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Affiliation(s)
- Pek Siew Lim
- Discipline of Biomedical Sciences, Faculty of Applied Science, University of Canberra, Canberra, ACT, Australia
| | - Christopher Ray Sutton
- Discipline of Biomedical Sciences, Faculty of Applied Science, University of Canberra, Canberra, ACT, Australia
| | - Sudha Rao
- Discipline of Biomedical Sciences, Faculty of Applied Science, University of Canberra, Canberra, ACT, Australia
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28
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Abstract
Precise control of the amplitude of protein kinase C (PKC) signalling is essential for cellular homoeostasis, and disruption of this control leads to pathophysiological states such as cancer, neurodegeneration and diabetes. For conventional and novel PKC, this amplitude is meticulously tuned by multiple inputs that regulate the amount of enzyme in the cell, its ability to sense its allosteric activator diacylglycerol, and protein scaffolds that co-ordinate access to substrates. Key to regulation of the signalling output of most PKC isoenzymes is the ability of cytosolic enzyme to respond to the membrane-embedded lipid second messenger, diacylglycerol, in a dynamic range that prevents signalling in the absence of agonists but allows efficient activation in response to small changes in diacylglycerol levels. The present review discusses the regulatory inputs that control the spatiotemporal dynamics of PKC signalling, with a focus on conventional and novel PKC isoenzymes.
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29
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Abstract
Protein kinase C (PKC) is comprised of a family of signal-regulated enzymes that play pleiotropic roles in the control of many physiological and pathological responses. PKC isoforms are traditionally viewed as allosterically activated enzymes that are recruited to membranes by growth factor receptor-generated lipid cofactors. An inherent assumption of this conventional model of PKC isoform activation is that PKCs act exclusively at membrane-delimited substrates and that PKC catalytic activity is an inherent property of each enzyme that is not altered by the activation process. This traditional model of PKC activation does not adequately explain the many well-documented actions of PKC enzymes in mitochondrial, nuclear, and cardiac sarcomeric (non-sarcolemmal) subcellular compartments. Recent studies address this dilemma by identifying stimulus-specific differences in the mechanisms for PKC isoform activation during growth factor activation versus oxidative stress. This review discusses a number of non-canonical redox-triggered mechanisms that can alter the catalytic properties and subcellular compartmentation patterns of PKC enzymes. While some redox-activated mechanisms act at structural determinants that are common to all PKCs, the redox-dependent mechanism for PKCδ activation requires Src-dependent tyrosine phosphorylation of a unique phosphorylation motif on this enzyme and is isoform specific. Since oxidative stress contributes to pathogenesis of a wide range of clinical disorders, these stimulus-specific differences in the controls and consequences of PKC activation have important implications for the design and evaluation of PKC-targeted therapeutics.
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Affiliation(s)
- Susan F Steinberg
- Department of Pharmacology, College of Physicians and Surgeons, Columbia University New York, NY, USA
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30
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Gao R, Liu Y, Silva-Fernandes A, Fang X, Paulucci-Holthauzen A, Chatterjee A, Zhang HL, Matsuura T, Choudhary S, Ashizawa T, Koeppen AH, Maciel P, Hazra TK, Sarkar PS. Inactivation of PNKP by mutant ATXN3 triggers apoptosis by activating the DNA damage-response pathway in SCA3. PLoS Genet 2015; 11:e1004834. [PMID: 25590633 DOI: 10.1371/journal.pgen.1004834] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 10/16/2014] [Indexed: 12/30/2022] Open
Abstract
Spinocerebellar ataxia type 3 (SCA3), also known as Machado-Joseph disease (MJD), is an untreatable autosomal dominant neurodegenerative disease, and the most common such inherited ataxia worldwide. The mutation in SCA3 is the expansion of a polymorphic CAG tri-nucleotide repeat sequence in the C-terminal coding region of the ATXN3 gene at chromosomal locus 14q32.1. The mutant ATXN3 protein encoding expanded glutamine (polyQ) sequences interacts with multiple proteins in vivo, and is deposited as aggregates in the SCA3 brain. A large body of literature suggests that the loss of function of the native ATNX3-interacting proteins that are deposited in the polyQ aggregates contributes to cellular toxicity, systemic neurodegeneration and the pathogenic mechanism in SCA3. Nonetheless, a significant understanding of the disease etiology of SCA3, the molecular mechanism by which the polyQ expansions in the mutant ATXN3 induce neurodegeneration in SCA3 has remained elusive. In the present study, we show that the essential DNA strand break repair enzyme PNKP (polynucleotide kinase 3’-phosphatase) interacts with, and is inactivated by, the mutant ATXN3, resulting in inefficient DNA repair, persistent accumulation of DNA damage/strand breaks, and subsequent chronic activation of the DNA damage-response ataxia telangiectasia-mutated (ATM) signaling pathway in SCA3. We report that persistent accumulation of DNA damage/strand breaks and chronic activation of the serine/threonine kinase ATM and the downstream p53 and protein kinase C-δ pro-apoptotic pathways trigger neuronal dysfunction and eventually neuronal death in SCA3. Either PNKP overexpression or pharmacological inhibition of ATM dramatically blocked mutant ATXN3-mediated cell death. Discovery of the mechanism by which mutant ATXN3 induces DNA damage and amplifies the pro-death signaling pathways provides a molecular basis for neurodegeneration due to PNKP inactivation in SCA3, and for the first time offers a possible approach to treatment. Spinocerebellar ataxia type 3 (SCA3) is an untreatable neurodegenerative disease, and the most common dominantly inherited ataxia worldwide. SCA3 is caused by expansion of a CAG tri-nucleotide repeat sequence in the ATXN3 gene’s coding region. The expanded CAG sequences encode a run of the amino acid glutamine; the mutant ATXN3 interacts with multiple proteins in vivo to create insoluble aggregates in SCA3 brains. It is thought that the loss of function of the aggregated proteins contributes to cellular toxicity and neurodegeneration in SCA3. Despite significant progress in understanding SCA3’s etiology, the molecular mechanism by which the mutant protein triggers the death of neurons in SCA3 brains remains unknown. We now report that the mutant ATXN3 protein interacts with and inactivates PNKP (polynucleotide kinase 3’-phosphatase), an essential DNA strand break repair enzyme. This inactivation results in persistent accumulation of DNA damage, and chronic activation of the DNA damage-response ATM signaling pathway in SCA3. Our work suggests that persistent DNA damage/strand breaks and chronic activation of ATM trigger neuronal death in SCA3. Discovery of the mechanism by which mutant ATXN3 induces DNA damage and amplifies the pro-death pathways provides a molecular basis for neurodegeneration in SCA3, and perhaps ultimately for its treatment.
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Hoque M, Rentero C, Cairns R, Tebar F, Enrich C, Grewal T. Annexins — Scaffolds modulating PKC localization and signaling. Cell Signal 2014; 26:1213-25. [DOI: 10.1016/j.cellsig.2014.02.012] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 02/22/2014] [Indexed: 12/15/2022]
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Wie SM, Adwan TS, DeGregori J, Anderson SM, Reyland ME. Inhibiting tyrosine phosphorylation of protein kinase Cδ (PKCδ) protects the salivary gland from radiation damage. J Biol Chem 2014; 289:10900-10908. [PMID: 24569990 DOI: 10.1074/jbc.m114.551366] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Radiation therapy for head and neck cancer can result in extensive damage to normal adjacent tissues such as the salivary gland and oral mucosa. We have shown previously that tyrosine phosphorylation at Tyr-64 and Tyr-155 activates PKCδ in response to apoptotic stimuli by facilitating its nuclear import. Here we have identified the tyrosine kinases that mediate activation of PKCδ in apoptotic cells and have explored the use of tyrosine kinase inhibitors for suppression of irradiation-induced apoptosis. We identify the damage-inducible kinase, c-Abl, as the PKCδ Tyr-155 kinase and c-Src as the Tyr-64 kinase. Depletion of c-Abl or c-Src with shRNA decreased irradiation- and etoposide-induced apoptosis, suggesting that inhibitors of these kinases may be useful therapeutically. Pretreatment with dasatinib, a broad spectrum tyrosine kinase inhibitor, blocked phosphorylation of PKCδ at both Tyr-64 and Tyr-155. Expression of "gate-keeper" mutants of c-Abl or c-Src that are active in the presence of dasatinib restored phosphorylation of PKCδ at Tyr-155 and Tyr-64, respectively. Imatinib, a c-Abl-selective inhibitor, also specifically blocked PKCδ Tyr-155 phosphorylation. Dasatinib and imatinib both blocked binding of PKCδ to importin-α and nuclear import, demonstrating that tyrosine kinase inhibitors can inhibit nuclear accumulation of PKCδ. Likewise, pretreatment with dasatinib also suppressed etoposide and radiation induced apoptosis in vitro. In vivo, pre-treatment of mice with dasatinib blocked radiation-induced apoptosis in the salivary gland by >60%. These data suggest that tyrosine kinase inhibitors may be useful prophylactically for protection of nontumor tissues in patients undergoing radiotherapy of the head and neck.
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Affiliation(s)
- Sten M Wie
- Program in Structural Biology and Biochemistry; Department of Craniofacial Biology, School of Dental Medicine, University of Colorado, Anschutz Medical Campus, Aurora, Colorado 80045
| | - Tariq S Adwan
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado, Anschutz Medical Campus, Aurora, Colorado 80045
| | - James DeGregori
- Department of Biochemistry and Molecular Genetics, University of Colorado, Anschutz Medical Campus, Aurora, Colorado 80045
| | - Steven M Anderson
- Department of Pathology, School of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, Colorado 80045
| | - Mary E Reyland
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado, Anschutz Medical Campus, Aurora, Colorado 80045.
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Erlejman AG, Lagadari M, Toneatto J, Piwien-pilipuk G, Galigniana MD. Regulatory role of the 90-kDa-heat-shock protein (Hsp90) and associated factors on gene expression. Biochimica et Biophysica Acta (BBA) - Gene Regulatory Mechanisms 2014; 1839:71-87. [DOI: 10.1016/j.bbagrm.2013.12.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Revised: 12/23/2013] [Accepted: 12/26/2013] [Indexed: 12/31/2022]
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Abstract
Protein kinase C (PKC) has been a tantalizing target for drug discovery ever since it was first identified as the receptor for the tumour promoter phorbol ester in 1982. Although initial therapeutic efforts focused on cancer, additional indications--including diabetic complications, heart failure, myocardial infarction, pain and bipolar disorder--were targeted as researchers developed a better understanding of the roles of eight conventional and novel PKC isozymes in health and disease. Unfortunately, both academic and pharmaceutical efforts have yet to result in the approval of a single new drug that specifically targets PKC. Why does PKC remain an elusive drug target? This Review provides a short account of some of the efforts, challenges and opportunities in developing PKC modulators to address unmet clinical needs.
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35
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Allen-Petersen BL, Carter CJ, Ohm AM, Reyland ME. Protein kinase Cδ is required for ErbB2-driven mammary gland tumorigenesis and negatively correlates with prognosis in human breast cancer. Oncogene 2013; 33:1306-15. [PMID: 23474764 DOI: 10.1038/onc.2013.59] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 12/04/2012] [Accepted: 12/21/2012] [Indexed: 02/07/2023]
Abstract
Protein kinase C δ (PKCδ) regulates apoptosis in the mammary gland, however, the functional contribution of PKCδ to the development or progression of breast cancer has yet to be determined. Meta-analysis of ErbB2-positive breast cancers shows increased PKCδ expression, and a negative correlation between PKCδ expression and prognosis. Here, we present in-vivo evidence that PKCδ is essential for the development of mammary gland tumors in a ErbB2-overexpressing transgenic mouse model, and in-vitro evidence that PKCδ is required for proliferative signaling downstream of the ErbB2 receptor. Mouse mammary tumor virus (MMTV)-ErbB2 mice lacking PKCδ (δKO) have increased tumor latency compared with MMTV-ErbB2 wild-type (δWT) mice, and the tumors show a dramatic decrease in Ki-67 staining. To explore the relationship between PKCδ and ErbB2-driven proliferation more directly, we used MCF-10A cells engineered to express a synthetic ligand-inducible form of the ErbB2 receptor. Depletion of PKCδ with short hairpin RNA inhibited ligand-induced growth in both two-dimensional (2D) (plastic) and three-dimensional (3D) (Matrigel) culture, and correlated with decreased phosphorylation of the ErbB2 receptor and reduced activation of Src and MAPK/ERK pathways. Similarly, in human breast cancer cell lines in which ErbB2 is overexpressed, depletion of PKCδ suppresses proliferation, Src and ERK activation. PKCδ appears to drive proliferation through the formation of an active ErbB2/PKCδ/Src signaling complex, as depletion of PKCδ disrupts association of Src with the ErbB2 receptor. Taken together, our studies present the first evidence that PKCδ is a critical regulator of ErbB2-mediated tumorigenesis, and suggest further investigation of PKCδ as a target in ErbB2-positive breast cancer.
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Affiliation(s)
- B L Allen-Petersen
- Program in Cell Biology, Stem Cells and Development, School of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
| | - C J Carter
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
| | - A M Ohm
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
| | - M E Reyland
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
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36
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Wu-Zhang AX, Murphy AN, Bachman M, Newton AC. Isozyme-specific interaction of protein kinase Cδ with mitochondria dissected using live cell fluorescence imaging. J Biol Chem 2012; 287:37891-906. [PMID: 22988234 DOI: 10.1074/jbc.m112.412635] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
PKCδ signaling to mitochondria has been implicated in both mitochondrial apoptosis and metabolism. However, the mechanism by which PKCδ interacts with mitochondria is not well understood. Using FRET-based imaging, we show that PKCδ interacts with mitochondria by a novel and isozyme-specific mechanism distinct from its canonical recruitment to other membranes such as the plasma membrane or Golgi. Specifically, we show that PKCδ interacts with mitochondria following stimulation with phorbol esters or, in L6 myocytes, with insulin via a mechanism that requires two steps. In the first step, PKCδ translocates acutely to mitochondria by a mechanism that requires its C1A and C1B domains and a Leu-Asn sequence in its turn motif. In the second step, PKCδ is retained at mitochondria by a mechanism that depends on its C2 domain, a unique Glu residue in its activation loop, intrinsic catalytic activity, and the mitochondrial membrane potential. In contrast, of these determinants, only the C1B domain is required for the phorbol ester-stimulated translocation of PKCδ to other membranes. PKCδ also basally localizes to mitochondria and increases mitochondrial respiration via many of the same determinants that promote its agonist-evoked interaction. PKCδ localized to mitochondria has robust activity, as revealed by a FRET reporter of PKCδ-specific activity (δCKAR). These data support a model in which multiple determinants unique to PKCδ drive a specific interaction with mitochondria that promotes mitochondrial respiration.
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Affiliation(s)
- Alyssa X Wu-Zhang
- Department of Pharmacology, University of California San Diego, La Jolla, California 92093, USA
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da Silva VCH, Ramos CHI. The network interaction of the human cytosolic 90 kDa heat shock protein Hsp90: A target for cancer therapeutics. J Proteomics 2012; 75:2790-802. [PMID: 22236519 DOI: 10.1016/j.jprot.2011.12.028] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 12/18/2011] [Accepted: 12/19/2011] [Indexed: 10/14/2022]
Abstract
In the cell, proteins interact within a network in which a small number of proteins are highly connected nodes or hubs. A disturbance in the hub proteins usually has a higher impact on the cell physiology than a disturbance in poorly connected nodes. In eukaryotes, the cytosolic Hsp90 is considered to be a hub protein as it interacts with molecular chaperones and co-chaperones, and has key regulatory proteins as clients, such as transcriptional factors, protein kinases and hormone receptors. The large number of Hsp90 partners suggests that Hsp90 is involved in very important functions, such as signaling, proteostasis and epigenetics. Some of these functions are dysregulated in cancer, making Hsp90 a potential target for therapeutics. The number of Hsp90 interactors appears to be so large that a precise answer to the question of how many proteins interact with this chaperone has no definitive answer yet, not even if the question refers to specific Hsp90s as one of the human cytosolic forms. Here we review the major chaperones and co-chaperones that interact with cytosolic Hsp90s, highlighting the latest findings regarding client proteins and the role that posttranslational modifications have on the function and interactions of these molecular chaperones. This article is part of a Special Issue entitled: Proteomics: The clinical link.
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Affiliation(s)
- Viviane C H da Silva
- Institute of Chemistry, University of Campinas-UNICAMP. P.O. Box 6154, 13083-970, Campinas, SP, Brazil
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