601
|
hPso4/hPrp19: a critical component of DNA repair and DNA damage checkpoint complexes. Oncogene 2015; 35:2279-86. [PMID: 26364595 DOI: 10.1038/onc.2015.321] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 07/16/2015] [Accepted: 07/19/2015] [Indexed: 12/15/2022]
Abstract
Genome integrity is vital to cellular homeostasis and its forfeiture is linked to deleterious consequences-cancer, immunodeficiency, genetic disorders and premature aging. The human ubiquitin ligase Pso4/Prp19 has emerged as a critical component of multiple DNA damage response (DDR) signaling networks. It not only senses DNA damage, binds double-stranded DNA in a sequence-independent manner, facilitates processing of damaged DNA, promotes DNA end joining, regulates replication protein A (RPA2) phosphorylation and ubiquitination at damaged DNA, but also regulates RNA splicing and mitotic spindle formation in its integral capacity as a scaffold for a multimeric core complex. Accordingly, by virtue of its regulatory and structural interactions with key proteins critical for genome integrity-DNA double-strand break (DSB) repair, DNA interstrand crosslink repair, repair of stalled replication forks and DNA end joining-it fills a unique niche in restoring genomic integrity after multiple types of DNA damage and thus has a vital role in maintaining chromatin integrity and cellular functions. These properties may underlie its ability to thwart replicative senescence and, not surprisingly, have been linked to the self-renewal and colony-forming ability of murine hematopoietic stem cells. This review highlights recent advances in hPso4 research that provides a fascinating glimpse into the pleiotropic activities of a ubiquitously expressed multifunctional E3 ubiquitin ligase.
Collapse
|
602
|
Wiegmans AP, Yap PY, Ward A, Lim YC, Khanna KK. Differences in Expression of Key DNA Damage Repair Genes after Epigenetic-Induced BRCAness Dictate Synthetic Lethality with PARP1 Inhibition. Mol Cancer Ther 2015; 14:2321-31. [PMID: 26294743 DOI: 10.1158/1535-7163.mct-15-0374] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 08/03/2015] [Indexed: 11/16/2022]
Abstract
The triple-negative breast cancer (TNBC) subtype represents a cancer that is highly aggressive with poor patient outcome. Current preclinical success has been gained through synthetic lethality, targeting genome instability with PARP inhibition in breast cancer cells that harbor silencing of the homologous recombination (HR) pathway. Histone deacetylase inhibitors (HDACi) are a class of drugs that mediate epigenetic changes in expression of HR pathway genes. Here, we compare the activity of the pan-HDAC inhibitor suberoylanilide hydroxamic acid (SAHA), the class I/IIa HDAC inhibitor valproic acid (VPA), and the HDAC1/2-specific inhibitor romidepsin (ROMI) for their capability to regulate DNA damage repair gene expression and in sensitizing TNBC to PARPi. We found that two of the HDACis tested, SAHA and ROMI, but not VPA, indeed inhibit HR repair and that RAD51, BARD1, and FANCD2 represent key proteins whose inhibition is required for HDACi-mediated therapy with PARP inhibition in TNBC. We also observed that restoration of BRCA1 function stabilizes the genome compared with mutant BRCA1 that results in enhanced polyploid population after combination treatment with HDACi and PARPi. Furthermore, we found that overexpression of the key HR protein RAD51 represents a mechanism for this resistance, promoting aberrant repair and the enhanced polyploidy observed. These findings highlight the key components of HR in guiding synthetic lethality with PARP inhibition and support the rationale for utilizing the novel combination of HDACi and PARPi against TNBC in the clinical setting.
Collapse
Affiliation(s)
- Adrian P Wiegmans
- Signal Transduction Laboratory, QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia. Tumour Microenvironment Laboratory, QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia.
| | - Pei-Yi Yap
- Signal Transduction Laboratory, QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Ambber Ward
- Signal Transduction Laboratory, QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Yi Chieh Lim
- Translational Brain Cancer Laboratory, QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Kum Kum Khanna
- Signal Transduction Laboratory, QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| |
Collapse
|
603
|
Jo U, Kim H. Exploiting the Fanconi Anemia Pathway for Targeted Anti-Cancer Therapy. Mol Cells 2015; 38:669-76. [PMID: 26194820 PMCID: PMC4546938 DOI: 10.14348/molcells.2015.0175] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 06/19/2015] [Indexed: 12/24/2022] Open
Abstract
Genome instability, primarily caused by faulty DNA repair mechanisms, drives tumorigenesis. Therapeutic interventions that exploit deregulated DNA repair in cancer have made considerable progress by targeting tumor-specific alterations of DNA repair factors, which either induces synthetic lethality or augments the efficacy of conventional chemotherapy and radiotherapy. The study of Fanconi anemia (FA), a rare inherited blood disorder and cancer predisposition syndrome, has been instrumental in understanding the extent to which DNA repair defects contribute to tumorigenesis. The FA pathway functions to resolve blocked replication forks in response to DNA interstrand cross-links (ICLs), and accumulating knowledge of its activation by the ubiquitin-mediated signaling pathway has provided promising therapeutic opportunities for cancer treatment. Here, we discuss recent advances in our understanding of FA pathway regulation and its potential application for designing tailored therapeutics that take advantage of deregulated DNA ICL repair in cancer.
Collapse
Affiliation(s)
- Ukhyun Jo
- Department of Pharmacological Sciences, Stony Brook University, New York 11794,
USA
| | - Hyungjin Kim
- Department of Pharmacological Sciences, Stony Brook University, New York 11794,
USA
| |
Collapse
|
604
|
Hopkins TA, Shi Y, Rodriguez LE, Solomon LR, Donawho CK, DiGiammarino EL, Panchal SC, Wilsbacher JL, Gao W, Olson AM, Stolarik DF, Osterling DJ, Johnson EF, Maag D. Mechanistic Dissection of PARP1 Trapping and the Impact on In Vivo Tolerability and Efficacy of PARP Inhibitors. Mol Cancer Res 2015. [PMID: 26217019 DOI: 10.1158/1541-7786.mcr-15-0191-t] [Citation(s) in RCA: 189] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
UNLABELLED Poly(ADP-ribose) polymerases (PARP1, -2, and -3) play important roles in DNA damage repair. As such, a number of PARP inhibitors are undergoing clinical development as anticancer therapies, particularly in tumors with DNA repair deficits and in combination with DNA-damaging agents. Preclinical evidence indicates that PARP inhibitors potentiate the cytotoxicity of DNA alkylating agents. It has been proposed that a major mechanism underlying this activity is the allosteric trapping of PARP1 at DNA single-strand breaks during base excision repair; however, direct evidence of allostery has not been reported. Here the data reveal that veliparib, olaparib, niraparib, and talazoparib (BMN-673) potentiate the cytotoxicity of alkylating agents. Consistent with this, all four drugs possess PARP1 trapping activity. Using biochemical and cellular approaches, we directly probe the trapping mechanism for an allosteric component. These studies indicate that trapping is due to catalytic inhibition and not allostery. The potency of PARP inhibitors with respect to trapping and catalytic inhibition is linearly correlated in biochemical systems but is nonlinear in cells. High-content imaging of γH2Ax levels suggests that this is attributable to differential potentiation of DNA damage in cells. Trapping potency is inversely correlated with tolerability when PARP inhibitors are combined with temozolomide in mouse xenograft studies. As a result, PARP inhibitors with dramatically different trapping potencies elicit comparable in vivo efficacy at maximum tolerated doses. Finally, the impact of trapping on tolerability and efficacy is likely to be context specific. IMPLICATIONS Understanding the context-specific relationships of trapping and catalytic inhibition with both tolerability and efficacy will aid in determining the suitability of a PARP inhibitor for inclusion in a particular clinical regimen.
Collapse
Affiliation(s)
| | - Yan Shi
- AbbVie, Inc., North Chicago, Illinois
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
605
|
Abstract
Although the two B-family human DNA polymerases, pol δ and pol ε, are responsible for the bulk of nuclear genome replication, at least 14 additional polymerases have roles in nuclear DNA repair and replication. In this issue, newly reported crystal structures of two specialized A-family polymerases, pol δ and pol ε, expose these enzymes’ strategies for handling aberrant DNA ends.
Collapse
|
606
|
van Schendel R, Roerink SF, Portegijs V, van den Heuvel S, Tijsterman M. Polymerase Θ is a key driver of genome evolution and of CRISPR/Cas9-mediated mutagenesis. Nat Commun 2015; 6:7394. [PMID: 26077599 PMCID: PMC4490562 DOI: 10.1038/ncomms8394] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 05/04/2015] [Indexed: 12/22/2022] Open
Abstract
Cells are protected from toxic DNA double-stranded breaks (DSBs) by a number of DNA repair mechanisms, including some that are intrinsically error prone, thus resulting in mutations. To what extent these mechanisms contribute to evolutionary diversification remains unknown. Here, we demonstrate that the A-family polymerase theta (POLQ) is a major driver of inheritable genomic alterations in Caenorhabditis elegans. Unlike somatic cells, which use non-homologous end joining (NHEJ) to repair DNA transposon-induced DSBs, germ cells use polymerase theta-mediated end joining, a conceptually simple repair mechanism requiring only one nucleotide as a template for repair. Also CRISPR/Cas9-induced genomic changes are exclusively generated through polymerase theta-mediated end joining, refuting a previously assumed requirement for NHEJ in their formation. Finally, through whole-genome sequencing of propagated populations, we show that only POLQ-proficient animals accumulate genomic scars that are abundantly present in genomes of wild C. elegans, pointing towards POLQ as a major driver of genome diversification.
Collapse
Affiliation(s)
- Robin van Schendel
- Department of Human Genetics, Leiden University Medical Center, PO Box 9600, 2300 RC, Leiden, The Netherlands
| | - Sophie F. Roerink
- Department of Human Genetics, Leiden University Medical Center, PO Box 9600, 2300 RC, Leiden, The Netherlands
| | - Vincent Portegijs
- Department of Biology, Division of Developmental Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Sander van den Heuvel
- Department of Biology, Division of Developmental Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Marcel Tijsterman
- Department of Human Genetics, Leiden University Medical Center, PO Box 9600, 2300 RC, Leiden, The Netherlands
| |
Collapse
|
607
|
Sistigu A, Manic G, Obrist F, Vitale I. Trial watch - inhibiting PARP enzymes for anticancer therapy. Mol Cell Oncol 2015; 3:e1053594. [PMID: 27308587 DOI: 10.1080/23723556.2015.1053594] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 05/16/2015] [Accepted: 05/18/2015] [Indexed: 12/25/2022]
Abstract
Poly(ADP-ribose) polymerases (PARPs) are a members of family of enzymes that catalyze poly(ADP-ribosyl)ation (PARylation) and/or mono(ADP-ribosyl)ation (MARylation), two post-translational protein modifications involved in crucial cellular processes including (but not limited to) the DNA damage response (DDR). PARP1, the most abundant family member, is a nuclear protein that is activated upon sensing distinct types of DNA damage and contributes to their resolution by PARylating multiple DDR players. Recent evidence suggests that, along with DDR, activated PARP1 mediates a series of prosurvival and proapoptotic processes aimed at preserving genomic stability. Despite this potential oncosuppressive role, upregulation and/or overactivation of PARP1 or other PARP enzymes has been reported in a variety of human neoplasms. Over the last few decades, several pharmacologic inhibitors of PARP1 and PARP2 have been assessed in preclinical and clinical studies showing potent antineoplastic activity, particularly against homologous recombination (HR)-deficient ovarian and breast cancers. In this Trial Watch, we describe the impact of PARP enzymes and PARylation in cancer, discuss the mechanism of cancer cell killing by PARP1 inactivation, and summarize the results of recent clinical studies aimed at evaluating the safety and therapeutic profile of PARP inhibitors in cancer patients.
Collapse
Affiliation(s)
| | - Gwenola Manic
- Regina Elena National Cancer Institute , Rome, Italy
| | - Florine Obrist
- Université Paris-Sud/Paris XI, Le Kremlin-Bicêtre, France; INSERM, UMRS1138, Paris, France; Equipe 11 labelisée par la Ligue Nationale contre le Cancer, Center de Recherche des Cordeliers, Paris, France; Gustave Roussy Cancer Campus, Villejuif, France
| | - Ilio Vitale
- Regina Elena National Cancer Institute, Rome, Italy; Department of Biology, University of Rome "TorVergata", Rome, Italy
| |
Collapse
|
608
|
Lee JS, Grav LM, Lewis NE, Faustrup Kildegaard H. CRISPR/Cas9-mediated genome engineering of CHO cell factories: Application and perspectives. Biotechnol J 2015; 10:979-94. [PMID: 26058577 DOI: 10.1002/biot.201500082] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 04/10/2015] [Accepted: 05/11/2015] [Indexed: 12/13/2022]
Abstract
Chinese hamster ovary (CHO) cells are the most widely used production host for therapeutic proteins. With the recent emergence of CHO genome sequences, CHO cell line engineering has taken on a new aspect through targeted genome editing. The bacterial clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) system enables rapid, easy and efficient engineering of mammalian genomes. It has a wide range of applications from modification of individual genes to genome-wide screening or regulation of genes. Facile genome editing using CRISPR/Cas9 empowers researchers in the CHO community to elucidate the mechanistic basis behind high level production of proteins and product quality attributes of interest. In this review, we describe the basis of CRISPR/Cas9-mediated genome editing and its application for development of next generation CHO cell factories while highlighting both future perspectives and challenges. As one of the main drivers for the CHO systems biology era, genome engineering with CRISPR/Cas9 will pave the way for rational design of CHO cell factories.
Collapse
Affiliation(s)
- Jae Seong Lee
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark
| | - Lise Marie Grav
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark
| | - Nathan E Lewis
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA.,The Novo Nordisk Foundation Center for Biosustainability at the University of California, San Diego School of Medicine, CA, USA
| | - Helene Faustrup Kildegaard
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark.
| |
Collapse
|
609
|
Abstract
The BRCA1 tumor suppressor protein is a central constituent of several distinct macromolecular protein complexes that execute homology-directed DNA damage repair and cell cycle checkpoints. Recent years have borne witness to an exciting phase of discovery at the basic molecular level for how this network of DNA repair proteins acts to maintain genome stability and suppress cancer. The clinical dividends of this investment are now being realized with the approval of first-in-class BRCA-targeted therapies for ovarian cancer and identification of molecular events that determine responsiveness to these agents. Further delineation of the basic science underlying BRCA network function holds promise to maximally exploit genome instability for hereditary and sporadic cancer therapy.
Collapse
Affiliation(s)
- Qinqin Jiang
- Departments of Cancer Biology and Pathology, Abramson Family Cancer Research Institute, and Basser Research Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Roger A Greenberg
- Departments of Cancer Biology and Pathology, Abramson Family Cancer Research Institute, and Basser Research Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104.
| |
Collapse
|
610
|
Javadekar SM, Raghavan SC. Snaps and mends: DNA breaks and chromosomal translocations. FEBS J 2015; 282:2627-45. [PMID: 25913527 DOI: 10.1111/febs.13311] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 03/29/2015] [Accepted: 04/23/2015] [Indexed: 01/11/2023]
Abstract
Integrity in entirety is the preferred state of any organism. The temporal and spatial integrity of the genome ensures continued survival of a cell. DNA breakage is the first step towards creation of chromosomal translocations. In this review, we highlight the factors contributing towards the breakage of chromosomal DNA. It has been well-established that the structure and sequence of DNA play a critical role in selective fragility of the genome. Several non-B-DNA structures such as Z-DNA, cruciform DNA, G-quadruplexes, R loops and triplexes have been implicated in generation of genomic fragility leading to translocations. Similarly, specific sequences targeted by proteins such as Recombination Activating Genes and Activation Induced Cytidine Deaminase are involved in translocations. Processes that ensure the integrity of the genome through repair may lead to persistence of breakage and eventually translocations if their actions are anomalous. An insufficient supply of nucleotides and chromatin architecture may also play a critical role. This review focuses on a range of events with the potential to threaten the genomic integrity of a cell, leading to cancer.
Collapse
Affiliation(s)
- Saniya M Javadekar
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| |
Collapse
|
611
|
Scott CL, Swisher EM, Kaufmann SH. Poly (ADP-ribose) polymerase inhibitors: recent advances and future development. J Clin Oncol 2015; 33:1397-406. [PMID: 25779564 PMCID: PMC4517072 DOI: 10.1200/jco.2014.58.8848] [Citation(s) in RCA: 274] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Poly (ADP-ribose) polymerase (PARP) inhibitors have shown promising activity in epithelial ovarian cancers, especially relapsed platinum-sensitive high-grade serous disease. Consistent with preclinical studies, ovarian cancers and a number of other solid tumor types occurring in patients with deleterious germline mutations in BRCA1 or BRCA2 seem to be particularly sensitive. However, it is also becoming clear that germline BRCA1/2 mutations are neither necessary nor sufficient for patients to derive benefit from PARP inhibitors. We provide an update on PARP inhibitor clinical development, describe recent advances in our understanding of PARP inhibitor mechanism of action, and discuss current issues in the development of these agents.
Collapse
Affiliation(s)
- Clare L Scott
- Clare L. Scott, Walter and Eliza Hall Institute of Medical Research and Royal Melbourne Hospital, Parkville, Victoria, Australia; Elizabeth M. Swisher, University of Washington, Seattle, WA; and Scott H. Kaufmann, Mayo Clinic, Rochester, MN
| | - Elizabeth M Swisher
- Clare L. Scott, Walter and Eliza Hall Institute of Medical Research and Royal Melbourne Hospital, Parkville, Victoria, Australia; Elizabeth M. Swisher, University of Washington, Seattle, WA; and Scott H. Kaufmann, Mayo Clinic, Rochester, MN
| | - Scott H Kaufmann
- Clare L. Scott, Walter and Eliza Hall Institute of Medical Research and Royal Melbourne Hospital, Parkville, Victoria, Australia; Elizabeth M. Swisher, University of Washington, Seattle, WA; and Scott H. Kaufmann, Mayo Clinic, Rochester, MN.
| |
Collapse
|
612
|
Zahn KE, Averill AM, Aller P, Wood RD, Doublié S. Human DNA polymerase θ grasps the primer terminus to mediate DNA repair. Nat Struct Mol Biol 2015; 22:304-11. [PMID: 25775267 PMCID: PMC4385486 DOI: 10.1038/nsmb.2993] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 02/13/2015] [Indexed: 01/14/2023]
Abstract
DNA polymerase θ protects against genomic instability via an alternative end-joining repair pathway for DNA double-strand breaks. Polymerase θ is overexpressed in breast, lung and oral cancers, and reduction of its activity in mammalian cells increases sensitivity to double-strand break-inducing agents, including ionizing radiation. Reported here are crystal structures of the C-terminal polymerase domain from human polymerase θ, illustrating two potential modes of dimerization. One structure depicts insertion of ddATP opposite an abasic-site analog during translesion DNA synthesis. The second structure describes a cognate ddGTP complex. Polymerase θ uses a specialized thumb subdomain to establish unique upstream contacts to the primer DNA strand, including an interaction with the 3'-terminal phosphate from one of five distinctive insertion loops. These observations demonstrate how polymerase θ grasps the primer to bypass DNA lesions or extend poorly annealed DNA termini to mediate end-joining.
Collapse
Affiliation(s)
- Karl E Zahn
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont, USA
| | - April M Averill
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont, USA
| | | | - Richard D Wood
- Department of Epigenetics &Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Smithville, Texas, USA
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont, USA
| |
Collapse
|
613
|
|
614
|
Killock D. Targeted therapies: DNA polymerase θ-a new target for synthetic lethality? Nat Rev Clin Oncol 2015; 12:125. [PMID: 25687907 DOI: 10.1038/nrclinonc.2015.23] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
615
|
Affiliation(s)
- Nam Woo Cho
- Departments of Cancer Biology and Pathology, Abramson Family Cancer Research Institute, Basser Research Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6160, USA
| | - Roger A Greenberg
- Departments of Cancer Biology and Pathology, Abramson Family Cancer Research Institute, Basser Research Center for BRCA, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6160, USA
| |
Collapse
|