1
|
Panda S, Roychowdhury T, Dutta A, Chakraborty S, Das T, Chatterjee S. ALTering Cancer by Triggering Telomere Replication Stress through the Stabilization of Promoter G-Quadruplex in SMARCAL1. ACS Chem Biol 2024; 19:1433-1439. [PMID: 38959478 DOI: 10.1021/acschembio.4c00285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
Most of the human cancers are dependent on telomerase to extend the telomeres. But ∼10% of all cancers use a telomerase-independent, homologous recombination mediated pathway called alternative lengthening of telomeres (ALT). Due to the poor prognosis, ALT status is not being considered yet in the diagnosis of cancer. No such specific treatment is available to date for ALT positive cancers. ALT positive cancers are dependent on replication stress to deploy DNA repair pathways to the telomeres to execute homologous recombination mediated telomere extension. SMARCAL1 (SWI/SNF related, matrix-associated, actin-dependent regulator of chromatin, subfamily A-like 1) is associated with the ALT telomeres to resolve replication stress thus providing telomere stability. Thus, the dependency on replication stress regulatory factors like SMARCAL1 made it a suitable therapeutic target for the treatment of ALT positive cancers. In this study, we found a significant downregulation of SMARCAL1 expression by stabilizing the G-quadruplex (G4) motif found in the promoter of SMARCAL1 by potent G4 stabilizers, like TMPyP4 and BRACO-19. SMARCAL1 downregulation led toward the increased localization of PML (promyelocytic leukemia) bodies in ALT telomeres and triggered the formation of APBs (ALT-associated promyelocytic leukemia bodies) in ALT positive cell lines, increasing telomere replication stress and DNA damage at a genomic level. Induction of replication stress and hyper-recombinogenic phenotype in ALT positive cells mediated by G4 stabilizing molecules already highlighted their possible application as a new therapeutic window to target ALT positive tumors. In accordance with this, our study will also provide a valuable insight toward the development of G4-based ALT therapeutics targeting SMARCAL1.
Collapse
Affiliation(s)
- Suman Panda
- Department of Biophysics, Bose Institute, EN 80, Sector V, Bidhan Nagar, Kolkata 700091 West Bengal, India
| | - Tanaya Roychowdhury
- Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1275 York Ave, New York, New York 10065, United States of America
| | - Anindya Dutta
- Department of Biophysics, Bose Institute, EN 80, Sector V, Bidhan Nagar, Kolkata 700091 West Bengal, India
| | - Sourio Chakraborty
- Division of Molecular Medicine, Centenary Campus, Bose Institute, P-1/12 C.I.T. Scheme VII-M, Kolkata 700054, India
| | - Tanya Das
- Division of Molecular Medicine, Centenary Campus, Bose Institute, P-1/12 C.I.T. Scheme VII-M, Kolkata 700054, India
| | - Subhrangsu Chatterjee
- Department of Biophysics, Bose Institute, EN 80, Sector V, Bidhan Nagar, Kolkata 700091 West Bengal, India
| |
Collapse
|
2
|
Iachettini S, Biroccio A, Zizza P. Therapeutic Use of G4-Ligands in Cancer: State-of-the-Art and Future Perspectives. Pharmaceuticals (Basel) 2024; 17:771. [PMID: 38931438 PMCID: PMC11206494 DOI: 10.3390/ph17060771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 05/31/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024] Open
Abstract
G-quadruplexes (G4s) are guanine-rich non-canonical secondary structures of nucleic acids that were identified in vitro almost half a century ago. Starting from the early 1980s, these structures were also observed in eukaryotic cells, first at the telomeric level and later in regulatory regions of cancer-related genes, in regulatory RNAs and within specific cell compartments such as lysosomes, mitochondria, and ribosomes. Because of the involvement of these structures in a large number of biological processes and in the pathogenesis of several diseases, including cancer, the interest in G4 targeting has exponentially increased in the last few years, and a great number of novel G4 ligands have been developed. Notably, G4 ligands represent a large family of heterogeneous molecules that can exert their functions by recognizing, binding, and stabilizing G4 structures in multiple ways. Regarding anti-cancer activity, the efficacy of G4 ligands was originally attributed to the capability of these molecules to inhibit the activity of telomerase, an enzyme that elongates telomeres and promotes endless replication in cancer cells. Thereafter, novel mechanisms through which G4 ligands exert their antitumoral activities have been defined, including the induction of DNA damage, control of gene expression, and regulation of metabolic pathways, among others. Here, we provided a perspective on the structure and function of G4 ligands with particular emphasis on their potential role as antitumoral agents. In particular, we critically examined the problems associated with the clinical translation of these molecules, trying to highlight the main aspects that should be taken into account during the phases of drug design and development. Indeed, taking advantage of the successes and failures, and the more recent technological progresses in the field, it would be possible to hypothesize the development of these molecules in the future that would represent a valid option for those cancers still missing effective therapies.
Collapse
Affiliation(s)
| | | | - Pasquale Zizza
- Translational Oncology Research Unit, IRCCS—Regina Elena National Cancer Institute, Via Elio Chianesi, 53, 00144 Roma, Italy; (S.I.); (A.B.)
| |
Collapse
|
3
|
Choudhury SD, Kumar P, Choudhury D. Bioactive nutraceuticals as G4 stabilizers: potential cancer prevention and therapy-a critical review. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2024; 397:3585-3616. [PMID: 38019298 DOI: 10.1007/s00210-023-02857-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 11/13/2023] [Indexed: 11/30/2023]
Abstract
G-quadruplexes (G4) are non-canonical, four-stranded, nucleic acid secondary structures formed in the guanine-rich sequences, where guanine nucleotides associate with each other via Hoogsteen hydrogen bonding. These structures are widely found near the functional regions of the mammalian genome, such as telomeres, oncogenic promoters, and replication origins, and play crucial regulatory roles in replication and transcription. Destabilization of G4 by various carcinogenic agents allows oncogene overexpression and extension of telomeric ends resulting in dysregulation of cellular growth-promoting oncogenesis. Therefore, targeting and stabilizing these G4 structures with potential ligands could aid cancer prevention and therapy. The field of G-quadruplex targeting is relatively nascent, although many articles have demonstrated the effect of G4 stabilization on oncogenic expressions; however, no previous study has provided a comprehensive analysis about the potency of a wide variety of nutraceuticals and some of their derivatives in targeting G4 and the lattice of oncogenic cell signaling cascade affected by them. In this review, we have discussed bioactive G4-stabilizing nutraceuticals, their sources, mode of action, and their influence on cellular signaling, and we believe our insight would bring new light to the current status of the field and motivate researchers to explore this relatively poorly studied arena.
Collapse
Affiliation(s)
- Satabdi Datta Choudhury
- Department of Chemistry and Biochemistry, Thapar Institute of Engineering and Technology, Patiala, Punjab, 147004, India
| | - Prateek Kumar
- School of Basic Sciences, Indian Institute of Technology (IIT), Mandi, Himachal Pradesh, 175005, India
| | - Diptiman Choudhury
- Department of Chemistry and Biochemistry, Thapar Institute of Engineering and Technology, Patiala, Punjab, 147004, India.
- Centre for Excellence in Emerging Materials, Thapar Institute of Engineering and Technology, Patiala, Punjab, 147004, India.
| |
Collapse
|
4
|
Johnson S, Paul T, Sanford S, Schnable BL, Detwiler A, Thosar S, Van Houten B, Myong S, Opresko P. BG4 antibody can recognize telomeric G-quadruplexes harboring destabilizing base modifications and lesions. Nucleic Acids Res 2024; 52:1763-1778. [PMID: 38153143 PMCID: PMC10939409 DOI: 10.1093/nar/gkad1209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 11/30/2023] [Accepted: 12/11/2023] [Indexed: 12/29/2023] Open
Abstract
BG4 is a single-chain variable fragment antibody shown to bind various G-quadruplex (GQ) topologies with high affinity and specificity, and to detect GQ in cells, including GQ structures formed within telomeric TTAGGG repeats. Here, we used ELISA and single-molecule pull-down (SiMPull) detection to test how various lengths and GQ destabilizing base modifications in telomeric DNA constructs alter BG4 binding. We observed high-affinity BG4 binding to telomeric GQ independent of telomere length, although three telomeric repeat constructs that cannot form stable intramolecular GQ showed reduced affinity. A single guanine substitution with 8-aza-7-deaza-G, T, A, or C reduced affinity to varying degrees depending on the location and base type, whereas two G substitutions in the telomeric construct dramatically reduced or abolished binding. Substitution with damaged bases 8-oxoguanine and O6-methylguanine failed to prevent BG4 binding although affinity was reduced depending on lesion location. SiMPull combined with FRET revealed that BG4 binding promotes folding of telomeric GQ harboring a G to T substitution or 8-oxoguanine. Atomic force microscopy revealed that BG4 binds telomeric GQ with a 1:1 stoichiometry. Collectively, our data suggest that BG4 can recognize partially folded telomeric GQ structures and promote telomeric GQ stability.
Collapse
Affiliation(s)
- Samuel A Johnson
- Department of Environmental and Occupational Health, University of Pittsburgh School of Public Health, Pittsburgh, PA 15261, USA
- UPMC Hillman Cancer Center, Pittsburgh, PA 15213, USA
- Molecular Biophysics and Structural Biology Graduate Program, University of Pittsburgh, PA 15260, USA
| | - Tapas Paul
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Samantha L Sanford
- Department of Environmental and Occupational Health, University of Pittsburgh School of Public Health, Pittsburgh, PA 15261, USA
- UPMC Hillman Cancer Center, Pittsburgh, PA 15213, USA
| | - Brittani L Schnable
- UPMC Hillman Cancer Center, Pittsburgh, PA 15213, USA
- Molecular Biophysics and Structural Biology Graduate Program, University of Pittsburgh, PA 15260, USA
| | - Ariana C Detwiler
- Department of Environmental and Occupational Health, University of Pittsburgh School of Public Health, Pittsburgh, PA 15261, USA
- UPMC Hillman Cancer Center, Pittsburgh, PA 15213, USA
| | - Sanjana A Thosar
- Department of Environmental and Occupational Health, University of Pittsburgh School of Public Health, Pittsburgh, PA 15261, USA
- UPMC Hillman Cancer Center, Pittsburgh, PA 15213, USA
| | - Bennett Van Houten
- UPMC Hillman Cancer Center, Pittsburgh, PA 15213, USA
- Molecular Biophysics and Structural Biology Graduate Program, University of Pittsburgh, PA 15260, USA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, PA 15213, USA
| | - Sua Myong
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Patricia L Opresko
- Department of Environmental and Occupational Health, University of Pittsburgh School of Public Health, Pittsburgh, PA 15261, USA
- UPMC Hillman Cancer Center, Pittsburgh, PA 15213, USA
- Molecular Biophysics and Structural Biology Graduate Program, University of Pittsburgh, PA 15260, USA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, PA 15213, USA
| |
Collapse
|
5
|
Thosar SA, Barnes RP, Detwiler A, Bhargava R, Wondisford A, O'Sullivan RJ, Opresko PL. Oxidative guanine base damage plays a dual role in regulating productive ALT-associated homology-directed repair. Cell Rep 2024; 43:113656. [PMID: 38194346 PMCID: PMC10851105 DOI: 10.1016/j.celrep.2023.113656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 11/06/2023] [Accepted: 12/20/2023] [Indexed: 01/10/2024] Open
Abstract
Cancer cells maintain telomeres by upregulating telomerase or alternative lengthening of telomeres (ALT) via homology-directed repair at telomeric DNA breaks. 8-Oxoguanine (8oxoG) is a highly prevalent endogenous DNA lesion in telomeric sequences, altering telomere structure and telomerase activity, but its impact on ALT is unclear. Here, we demonstrate that targeted 8oxoG formation at telomeres stimulates ALT activity and homologous recombination specifically in ALT cancer cells. Mechanistically, an acute 8oxoG induction increases replication stress, as evidenced by increased telomere fragility and ATR kinase activation at ALT telomeres. Furthermore, ALT cells are more sensitive to chronic telomeric 8oxoG damage than telomerase-positive cancer cells, consistent with increased 8oxoG-induced replication stress. However, telomeric 8oxoG production in G2 phase, when ALT telomere elongation occurs, impairs telomeric DNA synthesis. Our study demonstrates that a common oxidative base lesion has a dual role in regulating ALT depending on when the damage arises in the cell cycle.
Collapse
Affiliation(s)
- Sanjana A Thosar
- Department of Environmental and Occupational Health, University of Pittsburgh School of Public Health, Pittsburgh, PA, USA; UPMC Hillman Cancer Center, Pittsburgh, PA, USA
| | - Ryan P Barnes
- Department of Environmental and Occupational Health, University of Pittsburgh School of Public Health, Pittsburgh, PA, USA; UPMC Hillman Cancer Center, Pittsburgh, PA, USA
| | - Ariana Detwiler
- Department of Environmental and Occupational Health, University of Pittsburgh School of Public Health, Pittsburgh, PA, USA; UPMC Hillman Cancer Center, Pittsburgh, PA, USA
| | - Ragini Bhargava
- UPMC Hillman Cancer Center, Pittsburgh, PA, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Anne Wondisford
- UPMC Hillman Cancer Center, Pittsburgh, PA, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Roderick J O'Sullivan
- UPMC Hillman Cancer Center, Pittsburgh, PA, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Patricia L Opresko
- Department of Environmental and Occupational Health, University of Pittsburgh School of Public Health, Pittsburgh, PA, USA; UPMC Hillman Cancer Center, Pittsburgh, PA, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| |
Collapse
|
6
|
Spegg V, Altmeyer M. Genome maintenance meets mechanobiology. Chromosoma 2024; 133:15-36. [PMID: 37581649 PMCID: PMC10904543 DOI: 10.1007/s00412-023-00807-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/20/2023] [Accepted: 07/26/2023] [Indexed: 08/16/2023]
Abstract
Genome stability is key for healthy cells in healthy organisms, and deregulated maintenance of genome integrity is a hallmark of aging and of age-associated diseases including cancer and neurodegeneration. To maintain a stable genome, genome surveillance and repair pathways are closely intertwined with cell cycle regulation and with DNA transactions that occur during transcription and DNA replication. Coordination of these processes across different time and length scales involves dynamic changes of chromatin topology, clustering of fragile genomic regions and repair factors into nuclear repair centers, mobilization of the nuclear cytoskeleton, and activation of cell cycle checkpoints. Here, we provide a general overview of cell cycle regulation and of the processes involved in genome duplication in human cells, followed by an introduction to replication stress and to the cellular responses elicited by perturbed DNA synthesis. We discuss fragile genomic regions that experience high levels of replication stress, with a particular focus on telomere fragility caused by replication stress at the ends of linear chromosomes. Using alternative lengthening of telomeres (ALT) in cancer cells and ALT-associated PML bodies (APBs) as examples of replication stress-associated clustered DNA damage, we discuss compartmentalization of DNA repair reactions and the role of protein properties implicated in phase separation. Finally, we highlight emerging connections between DNA repair and mechanobiology and discuss how biomolecular condensates, components of the nuclear cytoskeleton, and interfaces between membrane-bound organelles and membraneless macromolecular condensates may cooperate to coordinate genome maintenance in space and time.
Collapse
Affiliation(s)
- Vincent Spegg
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Matthias Altmeyer
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland.
| |
Collapse
|
7
|
Sobinoff AP, Di Maro S, Low RRJ, Benedetti R, Tomassi S, D'Aniello A, Russo R, Baglivo I, Chianese U, Pedone PV, Chambery A, Cesare AJ, Altucci L, Pickett HA, Cosconati S. Irreversible inhibition of TRF2 TRFH recruiting functions by a covalent cyclic peptide induces telomeric replication stress in cancer cells. Cell Chem Biol 2023; 30:1652-1665.e6. [PMID: 38065101 DOI: 10.1016/j.chembiol.2023.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 09/28/2023] [Accepted: 11/13/2023] [Indexed: 12/24/2023]
Abstract
The TRF2 shelterin component is an essential regulator of telomere homeostasis and genomic stability. Mutations in the TRF2TRFH domain physically impair t-loop formation and prevent the recruitment of several factors that promote efficient telomere replication, causing telomeric DNA damage. Here, we design, synthesize, and biologically test covalent cyclic peptides that irreversibly target the TRF2TRFH domain. We identify APOD53 as our most promising compound, as it consistently induces a telomeric DNA damage response in cancer cell lines. APOD53 forms a covalent adduct with a reactive cysteine residue present in the TRF2TRFH domain and induces phenotypes consistent with TRF2TRFH domain mutants. These include induction of a telomeric DNA damage response, increased telomeric replication stress, and impaired recruitment of RTEL1 and SLX4 to telomeres. We demonstrate that APOD53 impairs cancer cell growth and find that co-treatment with APOD53 can exacerbate telomere replication stress caused by the G4 stabilizer RHPS4 and low dose aphidicolin (APH).
Collapse
Affiliation(s)
- Alexander P Sobinoff
- Telomere Length Regulation Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - Salvatore Di Maro
- DiSTABiF, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100 Caserta, Italy
| | - Ronnie R J Low
- Genome Integrity Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - Rosaria Benedetti
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Vico L. De Crecchio 7, 80138 Naples, Italy; Azienda Ospedaliera Universitaria "Luigi Vanvitelli", Medical Epigenetics Program
| | - Stefano Tomassi
- Department of Pharmacy, University of Naples "Federico II", Via D. Montesano 49, 80131 Naples, Italy
| | - Antonia D'Aniello
- DiSTABiF, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100 Caserta, Italy
| | - Rosita Russo
- DiSTABiF, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100 Caserta, Italy
| | - Ilaria Baglivo
- DiSTABiF, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100 Caserta, Italy
| | - Ugo Chianese
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Vico L. De Crecchio 7, 80138 Naples, Italy
| | - Paolo V Pedone
- DiSTABiF, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100 Caserta, Italy
| | - Angela Chambery
- DiSTABiF, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100 Caserta, Italy
| | - Anthony J Cesare
- Genome Integrity Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - Lucia Altucci
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Vico L. De Crecchio 7, 80138 Naples, Italy; BIOGEM, 83031 Ariano Irpino, Italy; Azienda Ospedaliera Universitaria "Luigi Vanvitelli", Medical Epigenetics Program; IEOS CNR, Napoli, Italy
| | - Hilda A Pickett
- Telomere Length Regulation Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia.
| | - Sandro Cosconati
- DiSTABiF, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, 81100 Caserta, Italy.
| |
Collapse
|
8
|
Bai G, Endres T, Kühbacher U, Greer BH, Peacock EM, Crossley MP, Sathirachinda A, Cortez D, Eichman BF, Cimprich KA. HLTF Prevents G4 Accumulation and Promotes G4-induced Fork Slowing to Maintain Genome Stability. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.27.563641. [PMID: 37961428 PMCID: PMC10634870 DOI: 10.1101/2023.10.27.563641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
G-quadruplexes (G4s) form throughout the genome and influence important cellular processes, but their deregulation can challenge DNA replication fork progression and threaten genome stability. Here, we demonstrate an unexpected, dual role for the dsDNA translocase HLTF in G4 metabolism. First, we find that HLTF is enriched at G4s in the human genome and suppresses G4 accumulation throughout the cell cycle using its ATPase activity. This function of HLTF affects telomere maintenance by restricting alternative lengthening of telomeres, a process stimulated by G4s. We also show that HLTF and MSH2, a mismatch repair factor that binds G4s, act in independent pathways to suppress G4s and to promote resistance to G4 stabilization. In a second, distinct role, HLTF restrains DNA synthesis upon G4 stabilization by suppressing PrimPol-dependent repriming. Together, the dual functions of HLTF in the G4 response prevent DNA damage and potentially mutagenic replication to safeguard genome stability.
Collapse
|
9
|
Ali JH, Walter M. Combining old and new concepts in targeting telomerase for cancer therapy: transient, immediate, complete and combinatory attack (TICCA). Cancer Cell Int 2023; 23:197. [PMID: 37679807 PMCID: PMC10483736 DOI: 10.1186/s12935-023-03041-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 08/25/2023] [Indexed: 09/09/2023] Open
Abstract
Telomerase can overcome replicative senescence by elongation of telomeres but is also a specific element in most cancer cells. It is expressed more vastly than any other tumor marker. Telomerase as a tumor target inducing replicative immortality can be overcome by only one other mechanism: alternative lengthening of telomeres (ALT). This limits the probability to develop resistance to treatments. Moreover, telomerase inhibition offers some degree of specificity with a low risk of toxicity in normal cells. Nevertheless, only one telomerase antagonist reached late preclinical studies. The underlying causes, the pitfalls of telomerase-based therapies, and future chances based on recent technical advancements are summarized in this review. Based on new findings and approaches, we propose a concept how long-term survival in telomerase-based cancer therapies can be significantly improved: the TICCA (Transient Immediate Complete and Combinatory Attack) strategy.
Collapse
Affiliation(s)
- Jaber Haj Ali
- Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
- Institute of Clinical Chemistry and Laboratory Medicine, Universitätsmedizin Rostock, Ernst-Heydemann-Straße 6, 18057, Rostock, Germany
| | - Michael Walter
- Institute of Clinical Chemistry and Laboratory Medicine, Universitätsmedizin Rostock, Ernst-Heydemann-Straße 6, 18057, Rostock, Germany.
| |
Collapse
|
10
|
Sohn EJ, Goralsky JA, Shay JW, Min J. The Molecular Mechanisms and Therapeutic Prospects of Alternative Lengthening of Telomeres (ALT). Cancers (Basel) 2023; 15:cancers15071945. [PMID: 37046606 PMCID: PMC10093677 DOI: 10.3390/cancers15071945] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 03/14/2023] [Accepted: 03/15/2023] [Indexed: 04/14/2023] Open
Abstract
As detailed by the end replication problem, the linear ends of a cell's chromosomes, known as telomeres, shorten with each successive round of replication until a cell enters into a state of growth arrest referred to as senescence. To maintain their immortal proliferation capacity, cancer cells must employ a telomere maintenance mechanism, such as telomerase activation or the Alternative Lengthening of Telomeres pathway (ALT). With only 10-15% of cancers utilizing the ALT mechanism, progress towards understanding its molecular components and associated hallmarks has only recently been made. This review analyzes the advances towards understanding the ALT pathway by: (1) detailing the mechanisms associated with engaging the ALT pathway as well as (2) identifying potential therapeutic targets of ALT that may lead to novel cancer therapeutic treatments. Collectively, these studies indicate that the ALT molecular mechanisms involve at least two distinct pathways induced by replication stress and damage at telomeres. We suggest exploiting tumor dependency on ALT is a promising field of study because it suggests new approaches to ALT-specific therapies for cancers with poorer prognosis. While substantial progress has been made in the ALT research field, additional progress will be required to realize these advances into clinical practices to treat ALT cancers and improve patient prognoses.
Collapse
Affiliation(s)
- Eric J Sohn
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Julia A Goralsky
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Jerry W Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039, USA
| | - Jaewon Min
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY 10032, USA
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA
| |
Collapse
|
11
|
Wu S, Jiang L, Lei L, Fu C, Huang J, Hu Y, Dong Y, Chen J, Zeng Q. Crosstalk between G-quadruplex and ROS. Cell Death Dis 2023; 14:37. [PMID: 36653351 PMCID: PMC9849334 DOI: 10.1038/s41419-023-05562-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 12/25/2022] [Accepted: 01/05/2023] [Indexed: 01/19/2023]
Abstract
The excessive production of reactive oxygen species (ROS) can lead to single nucleic acid base damage, DNA strand breakage, inter- and intra-strand cross-linking of nucleic acids, and protein-DNA cross-linking involved in the pathogenesis of cancer, neurodegenerative diseases, and aging. G-quadruplex (G4) is a stacked nucleic acid structure that is ubiquitous across regulatory regions of multiple genes. Abnormal formation and destruction of G4s due to multiple factors, including cations, helicases, transcription factors (TFs), G4-binding proteins, and epigenetic modifications, affect gene replication, transcription, translation, and epigenetic regulation. Due to the lower redox potential of G-rich sequences and unique structural characteristics, G4s are highly susceptible to oxidative damage. Additionally, the formation, stability, and biological regulatory role of G4s are affected by ROS. G4s are involved in regulating gene transcription, translation, and telomere length maintenance, and are therefore key players in age-related degeneration. Furthermore, G4s also mediate the antioxidant process by forming stress granules and activating Nrf2, which is suggestive of their involvement in developing ROS-related diseases. In this review, we have summarized the crosstalk between ROS and G4s, and the possible regulatory mechanisms through which G4s play roles in aging and age-related diseases.
Collapse
Affiliation(s)
- Songjiang Wu
- Department of Dermatology, Third Xiangya Hospital, Central South University, 138 Tongzipo Road, 410013, Changsha, Hunan, PR China
| | - Ling Jiang
- Department of Dermatology, Third Xiangya Hospital, Central South University, 138 Tongzipo Road, 410013, Changsha, Hunan, PR China
| | - Li Lei
- Department of Dermatology, Third Xiangya Hospital, Central South University, 138 Tongzipo Road, 410013, Changsha, Hunan, PR China
| | - Chuhan Fu
- Department of Dermatology, Third Xiangya Hospital, Central South University, 138 Tongzipo Road, 410013, Changsha, Hunan, PR China
| | - Jinhua Huang
- Department of Dermatology, Third Xiangya Hospital, Central South University, 138 Tongzipo Road, 410013, Changsha, Hunan, PR China
| | - Yibo Hu
- Department of Dermatology, Third Xiangya Hospital, Central South University, 138 Tongzipo Road, 410013, Changsha, Hunan, PR China
| | - Yumeng Dong
- Department of Dermatology, Third Xiangya Hospital, Central South University, 138 Tongzipo Road, 410013, Changsha, Hunan, PR China
| | - Jing Chen
- Department of Dermatology, Third Xiangya Hospital, Central South University, 138 Tongzipo Road, 410013, Changsha, Hunan, PR China.
| | - Qinghai Zeng
- Department of Dermatology, Third Xiangya Hospital, Central South University, 138 Tongzipo Road, 410013, Changsha, Hunan, PR China.
| |
Collapse
|
12
|
Vinayagamurthy S, Bagri S, Mergny JL, Chowdhury S. Telomeres expand sphere of influence: emerging molecular impact of telomeres in non-telomeric functions. Trends Genet 2023; 39:59-73. [PMID: 36404192 PMCID: PMC7614491 DOI: 10.1016/j.tig.2022.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 09/12/2022] [Accepted: 10/26/2022] [Indexed: 11/18/2022]
Abstract
Although the impact of telomeres on physiology stands well established, a question remains: how do telomeres impact cellular functions at a molecular level? This is because current understanding limits the influence of telomeres to adjacent subtelomeric regions despite the wide-ranging impact of telomeres. Emerging work in two distinct aspects offers opportunities to bridge this gap. First, telomere-binding factors were found with non-telomeric functions. Second, locally induced DNA secondary structures called G-quadruplexes are notably abundant in telomeres, and gene regulatory regions genome wide. Many telomeric factors bind to G-quadruplexes for non-telomeric functions. Here we discuss a more general model of how telomeres impact the non-telomeric genome - through factors that associate at telomeres and genome wide - and influence cell-intrinsic functions, particularly aging, cancer, and pluripotency.
Collapse
Affiliation(s)
- Soujanya Vinayagamurthy
- Integrative and Functional Biology Unit, CSIR Institute of Genomics and Integrative Biology, New Delhi 110025, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Sulochana Bagri
- Integrative and Functional Biology Unit, CSIR Institute of Genomics and Integrative Biology, New Delhi 110025, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Jean-Louis Mergny
- Institute of Biophysics of the CAS, v.v.i. Královopolská 135, 612 65 Brno, Czech Republic; Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS, INSERM, Institut Polytechnique de Paris, 91128 Palaiseau, France
| | - Shantanu Chowdhury
- Integrative and Functional Biology Unit, CSIR Institute of Genomics and Integrative Biology, New Delhi 110025, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India; GNR Knowledge Centre for Genome and Informatics, CSIR Institute of Genomics and Integrative Biology, New Delhi 110025, India.
| |
Collapse
|
13
|
Udroiu I, Marinaccio J, Sgura A. Many Functions of Telomerase Components: Certainties, Doubts, and Inconsistencies. Int J Mol Sci 2022; 23:ijms232315189. [PMID: 36499514 PMCID: PMC9736166 DOI: 10.3390/ijms232315189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/23/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022] Open
Abstract
A growing number of studies have evidenced non-telomeric functions of "telomerase". Almost all of them, however, investigated the non-canonical effects of the catalytic subunit TERT, and not the telomerase ribonucleoprotein holoenzyme. These functions mainly comprise signal transduction, gene regulation and the increase of anti-oxidative systems. Although less studied, TERC (the RNA component of telomerase) has also been shown to be involved in gene regulation, as well as other functions. All this has led to the publication of many reviews on the subject, which, however, are often disseminating personal interpretations of experimental studies of other researchers as original proofs. Indeed, while some functions such as gene regulation seem ascertained, especially because mechanistic findings have been provided, other ones remain dubious and/or are contradicted by other direct or indirect evidence (e.g., telomerase activity at double-strand break site, RNA polymerase activity of TERT, translation of TERC, mitochondrion-processed TERC). In a critical study of the primary evidence so far obtained, we show those functions for which there is consensus, those showing contradictory results and those needing confirmation. The resulting picture, together with some usually neglected aspects, seems to indicate a link between TERT and TERC functions and cellular stemness and gives possible directions for future research.
Collapse
|
14
|
Judasz E, Lisiak N, Kopczyński P, Taube M, Rubiś B. The Role of Telomerase in Breast Cancer's Response to Therapy. Int J Mol Sci 2022; 23:12844. [PMID: 36361634 PMCID: PMC9654063 DOI: 10.3390/ijms232112844] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 10/13/2022] [Accepted: 10/24/2022] [Indexed: 11/26/2023] Open
Abstract
Currently, breast cancer appears to be the most widespread cancer in the world and the most common cause of cancer deaths. This specific type of cancer affects women in both developed and developing countries. Prevention and early diagnosis are very important factors for good prognosis. A characteristic feature of cancer cells is the ability of unlimited cell division, which makes them immortal. Telomeres, which are shortened with each cell division in normal cells, are rebuilt in cancer cells by the enzyme telomerase, which is expressed in more than 85% of cancers (up to 100% of adenocarcinomas, including breast cancer). Telomerase may have different functions that are related to telomeres or unrelated. It has been shown that high activity of the enzyme in cancer cells is associated with poor cell sensitivity to therapies. Therefore, telomerase has become a potential target for cancer therapies. The low efficacy of therapies has resulted in the search for new combined and more effective therapeutic methods, including the involvement of telomerase inhibitors and telomerase-targeted immunotherapy.
Collapse
Affiliation(s)
- Eliza Judasz
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 60-806 Poznan, Poland
| | - Natalia Lisiak
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 60-806 Poznan, Poland
| | - Przemysław Kopczyński
- Centre for Orthodontic Mini-Implants at the Department and Clinic of Maxillofacial Orthopedics and Orthodontics, Poznan University of Medical Sciences, 60-812 Poznan, Poland
| | - Magdalena Taube
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 60-806 Poznan, Poland
| | - Błażej Rubiś
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 60-806 Poznan, Poland
| |
Collapse
|
15
|
Gao J, Pickett HA. Targeting telomeres: advances in telomere maintenance mechanism-specific cancer therapies. Nat Rev Cancer 2022; 22:515-532. [PMID: 35790854 DOI: 10.1038/s41568-022-00490-1] [Citation(s) in RCA: 70] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/25/2022] [Indexed: 12/31/2022]
Abstract
Cancer cells establish replicative immortality by activating a telomere-maintenance mechanism (TMM), be it telomerase or the alternative lengthening of telomeres (ALT) pathway. Targeting telomere maintenance represents an intriguing opportunity to treat the vast majority of all cancer types. Whilst telomerase inhibitors have historically been heralded as promising anticancer agents, the reality has been more challenging, and there are currently no therapeutic options for cancer types that use ALT despite their aggressive nature and poor prognosis. In this Review, we discuss the mechanistic differences between telomere maintenance by telomerase and ALT, the current methods used to detect each mechanism, the utility of these tests for clinical diagnosis, and recent developments in the therapeutic strategies being employed to target both telomerase and ALT. We present notable developments in repurposing established therapeutic agents and new avenues that are emerging to target cancer types according to which TMM they employ. These opportunities extend beyond inhibition of telomere maintenance, by finding and exploiting inherent weaknesses in the telomeres themselves to trigger rapid cellular effects that lead to cell death.
Collapse
Affiliation(s)
- Jixuan Gao
- Telomere Length Regulation Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW, Australia
| | - Hilda A Pickett
- Telomere Length Regulation Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW, Australia.
| |
Collapse
|
16
|
Petermann E, Lan L, Zou L. Sources, resolution and physiological relevance of R-loops and RNA-DNA hybrids. Nat Rev Mol Cell Biol 2022; 23:521-540. [PMID: 35459910 DOI: 10.1038/s41580-022-00474-x] [Citation(s) in RCA: 109] [Impact Index Per Article: 54.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2022] [Indexed: 12/12/2022]
Abstract
RNA-DNA hybrids are generated during transcription, DNA replication and DNA repair and are crucial intermediates in these processes. When RNA-DNA hybrids are stably formed in double-stranded DNA, they displace one of the DNA strands and give rise to a three-stranded structure called an R-loop. R-loops are widespread in the genome and are enriched at active genes. R-loops have important roles in regulating gene expression and chromatin structure, but they also pose a threat to genomic stability, especially during DNA replication. To keep the genome stable, cells have evolved a slew of mechanisms to prevent aberrant R-loop accumulation. Although R-loops can cause DNA damage, they are also induced by DNA damage and act as key intermediates in DNA repair such as in transcription-coupled repair and RNA-templated DNA break repair. When the regulation of R-loops goes awry, pathological R-loops accumulate, which contributes to diseases such as neurodegeneration and cancer. In this Review, we discuss the current understanding of the sources of R-loops and RNA-DNA hybrids, mechanisms that suppress and resolve these structures, the impact of these structures on DNA repair and genome stability, and opportunities to therapeutically target pathological R-loops.
Collapse
Affiliation(s)
- Eva Petermann
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK
- Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, UK
| | - Li Lan
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA, USA
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Lee Zou
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA, USA.
- Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| |
Collapse
|
17
|
Alessandrini I, Percio S, Naghshineh E, Zuco V, Stacchiotti S, Gronchi A, Pasquali S, Zaffaroni N, Folini M. Telomere as a Therapeutic Target in Dedifferentiated Liposarcoma. Cancers (Basel) 2022; 14:2624. [PMID: 35681604 PMCID: PMC9179266 DOI: 10.3390/cancers14112624] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 05/20/2022] [Accepted: 05/23/2022] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Well-differentiated (WD)/dedifferentiated (DD) liposarcoma (LPS) accounts for ~60% of retroperitoneal sarcomas. WDLPS and DDLPS divergently evolve from a common precursor and are both marked by the amplification of the 12q13-q15 region, leading to the abnormal expression of MDM2, CDK4, and HMGA2 genes. DDLPS is a non-lipogenic disease associated with aggressive clinical behavior. Patients have limited therapeutic options, especially for advanced disease, and their outcome remains largely unsatisfactory. This evidence underlines the need for identifying and validating DDLPS-specific actionable targets to design novel biology-driven therapies. METHODS Following gene expression profiling of DDLPS clinical specimens, we observed the up-regulation of "telomere maintenance" (TMM) pathways in paired DD and WD components of DDLPS. Considering the relevance of TMM for LPS onset and progression, the activity of a telomeric G-quadruplex binder (RHPS4) was assessed in DDLPS patient-derived cell lines. RESULTS Equitoxic concentrations of RHPS4 in DDLPS cells altered telomeric c-circle levels, induced DNA damage, and resulted in the accumulation of γ-H2AX-stained micronuclei. This evidence was paralleled by an RHPS4-mediated reduction of in vitro cell migration and induction of apoptosis/autophagy. CONCLUSIONS Our findings support telomere as an intriguing therapeutic target in DDLPS and suggest G-quadruplex binders as innovative therapeutic agents.
Collapse
Affiliation(s)
- Irene Alessandrini
- Molecular Pharmacology Unit, Department of Applied Research and Technological Development, Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Via G.A. Amadeo 42, 20133 Milan, Italy; (I.A.); (S.P.); (E.N.); (V.Z.); (S.P.)
| | - Stefano Percio
- Molecular Pharmacology Unit, Department of Applied Research and Technological Development, Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Via G.A. Amadeo 42, 20133 Milan, Italy; (I.A.); (S.P.); (E.N.); (V.Z.); (S.P.)
| | - Eisa Naghshineh
- Molecular Pharmacology Unit, Department of Applied Research and Technological Development, Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Via G.A. Amadeo 42, 20133 Milan, Italy; (I.A.); (S.P.); (E.N.); (V.Z.); (S.P.)
| | - Valentina Zuco
- Molecular Pharmacology Unit, Department of Applied Research and Technological Development, Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Via G.A. Amadeo 42, 20133 Milan, Italy; (I.A.); (S.P.); (E.N.); (V.Z.); (S.P.)
| | - Silvia Stacchiotti
- Adult Mesenchymal Tumor and Rare Cancer Unit, Department of Cancer Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Via Venezian 1, 20133 Milan, Italy;
| | - Alessandro Gronchi
- Sarcoma Service, Department of Surgery, Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Via Venezian 1, 20133 Milan, Italy;
| | - Sandro Pasquali
- Molecular Pharmacology Unit, Department of Applied Research and Technological Development, Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Via G.A. Amadeo 42, 20133 Milan, Italy; (I.A.); (S.P.); (E.N.); (V.Z.); (S.P.)
- Sarcoma Service, Department of Surgery, Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Via Venezian 1, 20133 Milan, Italy;
| | - Nadia Zaffaroni
- Molecular Pharmacology Unit, Department of Applied Research and Technological Development, Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Via G.A. Amadeo 42, 20133 Milan, Italy; (I.A.); (S.P.); (E.N.); (V.Z.); (S.P.)
| | - Marco Folini
- Molecular Pharmacology Unit, Department of Applied Research and Technological Development, Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Via G.A. Amadeo 42, 20133 Milan, Italy; (I.A.); (S.P.); (E.N.); (V.Z.); (S.P.)
| |
Collapse
|
18
|
Li D, Hou K, Zhang K, Jia S. Regulation of Replication Stress in Alternative Lengthening of Telomeres by Fanconi Anaemia Protein. Genes (Basel) 2022; 13:genes13020180. [PMID: 35205225 PMCID: PMC8872277 DOI: 10.3390/genes13020180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/17/2022] [Accepted: 01/19/2022] [Indexed: 02/04/2023] Open
Abstract
Fanconi anaemia (FA)-related proteins function in interstrand crosslink (ICL) repair pathways and multiple damage repair pathways. Recent studies have found that FA proteins are involved in the regulation of replication stress (RS) in alternative lengthening of telomeres (ALT). Since ALT cells often exhibit high-frequency ATRX mutations and high levels of telomeric secondary structure, high levels of DNA damage and replicative stress exist in ALT cells. Persistent replication stress is required to maintain the activity of ALT mechanistically, while excessive replication stress causes ALT cell death. FA proteins such as FANCD2 and FANCM are involved in the regulation of this balance by resolving or inhibiting the formation of telomere secondary structures to stabilize stalled replication forks and promote break-induced repair (BIR) to maintain the survival of ALT tumour cells. Therefore, we review the role of FA proteins in replication stress in ALT cells, providing a rationale and direction for the targeted treatment of ALT tumours.
Collapse
|
19
|
Bellon M, Yuan Y, Nicot C. Transcription Independent Stimulation of Telomerase Enzymatic Activity by HTLV-I Tax Through Stimulation of IKK. JOURNAL OF CANCER SCIENCES 2021; 8. [PMID: 34938859 PMCID: PMC8691565 DOI: 10.13188/2377-9292.1000024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The persistence and spreading of HTLV-I infected cells relies upon their clonal expansion through cellular replication. The development of adult T cell leukemia (ATLL) occurs decades following primary infection by HTLV-I. Moreover, identical provirus integration sites have been found in samples recovered several years apart from infected individuals. These observations suggest that infected cells persist in the host for an extended period of time. To endure long term proliferation, HTLV-I pre-leukemic cells must acquire critical oncogenic events, two of which are the bypassing of apoptosis and replicative senescence. In the early stages of disease, interleukin-2 (IL-2)/IL-2R signaling likely plays a major role in combination with activation of anti-apoptotic pathways. Avoidance of replicative senescence in HTLV-I infected cells is achieved through reactivation of human telomerase (hTERT). We have previously shown that HTLV-I viral Tax transcriptionally activates the hTERT promoter. In this study we demonstrate that Tax can stimulate hTERT enzymatic activity independently of its transcriptional effects. We further show that this occurs through Tax-mediated NF-KB activating functions. Our results suggest that in ATLL cells acquire Tax-transcriptional and post-transcriptional events to elevate telomerase activity.
Collapse
Affiliation(s)
- M Bellon
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, USA
| | - Y Yuan
- Department of Pharmacology, Baylor College of Medicine, USA
| | - C Nicot
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, USA
| |
Collapse
|
20
|
Kent T, Clynes D. Alternative Lengthening of Telomeres: Lessons to Be Learned from Telomeric DNA Double-Strand Break Repair. Genes (Basel) 2021; 12:1734. [PMID: 34828344 PMCID: PMC8619803 DOI: 10.3390/genes12111734] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 10/22/2021] [Accepted: 10/28/2021] [Indexed: 12/25/2022] Open
Abstract
The study of the molecular pathways underlying cancer has given us important insights into how breaks in our DNA are repaired and the dire consequences that can occur when these processes are perturbed. Extensive research over the past 20 years has shown that the key molecular event underpinning a subset of cancers involves the deregulated repair of DNA double-strand breaks (DSBs) at telomeres, which in turn leads to telomere lengthening and the potential for replicative immortality. Here we discuss, in-depth, recent major breakthroughs in our understanding of the mechanisms underpinning this pathway known as the alternative lengthening of telomeres (ALT). We explore how this gives us important insights into how DSB repair at telomeres is regulated, with relevance to the cell-cycle-dependent regulation of repair, repair of stalled replication forks and the spatial regulation of DSB repair.
Collapse
Affiliation(s)
- Thomas Kent
- Molecular Haematology Unit, Radcliffe Department of Medicine, The MRC Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK;
| | - David Clynes
- Department of Oncology, The MRC Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK
| |
Collapse
|
21
|
Yang SY, Chang EYC, Lim J, Kwan HH, Monchaud D, Yip S, Stirling PC, Wong JMY. G-quadruplexes mark alternative lengthening of telomeres. NAR Cancer 2021; 3:zcab031. [PMID: 34316718 PMCID: PMC8294677 DOI: 10.1093/narcan/zcab031] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 06/29/2021] [Accepted: 07/05/2021] [Indexed: 11/12/2022] Open
Abstract
About 10-15% of all human cancer cells employ a telomerase-independent recombination-based telomere maintenance method, known as alternative lengthening of telomere (ALT), of which the full mechanism remains incompletely understood. While implicated in previous studies as the initiating signals for ALT telomere repair, the prevalence of non-canonical nucleic acid structures in ALT cancers remains unclear. Extending earlier reports, we observe higher levels of DNA/RNA hybrids (R-loops) in ALT-positive (ALT+) compared to telomerase-positive (TERT+) cells. Strikingly, we observe even more pronounced differences for an associated four-stranded nucleic acid structure, G-quadruplex (G4). G4 signals are found at the telomere and are broadly associated with telomere length and accompanied by DNA damage markers. We establish an interdependent relationship between ALT-associated G4s and R-loops and confirm that these two structures can be spatially linked into unique structures, G-loops, at the telomere. Additionally, stabilization of G4s and R-loops cooperatively enhances ALT-activity. However, co-stabilization at higher doses resulted in cytotoxicity in a synergistic manner. Nuclear G4 signals are significantly and reproducibly different between ALT+ and TERT+ low-grade glioma tumours. Together, we present G4 as a novel hallmark of ALT cancers with potential future applications as a convenient biomarker for identifying ALT+ tumours and as therapeutic targets.
Collapse
Affiliation(s)
- Sunny Y Yang
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, V6T 1Z3, Canada
| | | | - Joanne Lim
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, V6T 1Z3, Canada
| | - Harwood H Kwan
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, V6T 1Z3, Canada
| | - David Monchaud
- Institut de Chimie Moléculaire, ICMUB CNRS UMR 6302, UBFC Dijon, 21078 Dijon, France
| | - Stephen Yip
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, V6T 2B5 Canada
| | | | - Judy M Y Wong
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, V6T 1Z3, Canada
| |
Collapse
|
22
|
MacKenzie D, Watters AK, To JT, Young MW, Muratori J, Wilkoff MH, Abraham RG, Plummer MM, Zhang D. ALT Positivity in Human Cancers: Prevalence and Clinical Insights. Cancers (Basel) 2021; 13:2384. [PMID: 34069193 PMCID: PMC8156225 DOI: 10.3390/cancers13102384] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/07/2021] [Accepted: 05/11/2021] [Indexed: 02/08/2023] Open
Abstract
Many exciting advances in cancer-related telomere biology have been made in the past decade. Of these recent advances, great progress has also been made with respect to the Alternative Lengthening of Telomeres (ALT) pathway. Along with a better understanding of the molecular mechanism of this unique telomere maintenance pathway, many studies have also evaluated ALT activity in various cancer subtypes. We first briefly review and assess a variety of commonly used ALT biomarkers. Then, we provide both an update on ALT-positive (ALT+) tumor prevalence as well as a systematic clinical assessment of the presently studied ALT+ malignancies. Additionally, we discuss the pathogenetic alterations in ALT+ cancers, for example, the mutation status of ATRX and DAXX, and their correlations with the activation of the ALT pathway. Finally, we highlight important ALT+ clinical associations within each cancer subtype and subdivisions within, as well as their prognoses. We hope this alternative perspective will allow scientists, clinicians, and drug developers to have greater insight into the ALT cancers so that together, we may develop more efficacious treatments and improved management strategies to meet the urgent needs of cancer patients.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Maria M. Plummer
- Department of Biomedical Sciences, College of Osteopathic Medicine, New York Institute of Technology, Old Westbury, NY 11568, USA; (D.M.J.); (A.K.W.); (J.T.T.); (M.W.Y.); (J.M.); (M.H.W.); (R.G.A.)
| | - Dong Zhang
- Department of Biomedical Sciences, College of Osteopathic Medicine, New York Institute of Technology, Old Westbury, NY 11568, USA; (D.M.J.); (A.K.W.); (J.T.T.); (M.W.Y.); (J.M.); (M.H.W.); (R.G.A.)
| |
Collapse
|
23
|
The Multiple Facets of ATRX Protein. Cancers (Basel) 2021; 13:cancers13092211. [PMID: 34062956 PMCID: PMC8124985 DOI: 10.3390/cancers13092211] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/30/2021] [Accepted: 05/02/2021] [Indexed: 12/21/2022] Open
Abstract
Simple Summary The gene encoding for the epigenetic regulator ATRX is gaining a prominent position among the most important oncosuppressive genes of the human genome. ATRX gene somatic mutations are found across a number of diverse cancer types, suggesting its relevance in tumor induction and progression. In the present review, the multiple activities of ATRX protein are described in the light of the most recent literature available highlighting its multifaceted role in the caretaking of the human genome. Abstract ATRX gene codifies for a protein member of the SWI-SNF family and was cloned for the first time over 25 years ago as the gene responsible for a rare developmental disorder characterized by α-thalassemia and intellectual disability called Alpha Thalassemia/mental Retardation syndrome X-linked (ATRX) syndrome. Since its discovery as a helicase involved in alpha-globin gene transcriptional regulation, our understanding of the multiple roles played by the ATRX protein increased continuously, leading to the recognition of this multifaceted protein as a central “caretaker” of the human genome involved in cancer suppression. In this review, we report recent advances in the comprehension of the ATRX manifold functions that encompass heterochromatin epigenetic regulation and maintenance, telomere function, replicative stress response, genome stability, and the suppression of endogenous transposable elements and exogenous viral genomes.
Collapse
|
24
|
Zhang JM, Genois MM, Ouyang J, Lan L, Zou L. Alternative lengthening of telomeres is a self-perpetuating process in ALT-associated PML bodies. Mol Cell 2021; 81:1027-1042.e4. [PMID: 33453166 PMCID: PMC8245000 DOI: 10.1016/j.molcel.2020.12.030] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 11/03/2020] [Accepted: 12/15/2020] [Indexed: 01/16/2023]
Abstract
Alternative lengthening of telomeres (ALT) is mediated by break-induced replication (BIR), but how BIR is regulated at telomeres is poorly understood. Here, we show that telomeric BIR is a self-perpetuating process. By tethering PML-IV to telomeres, we induced telomere clustering in ALT-associated PML bodies (APBs) and a POLD3-dependent ATR response at telomeres, showing that BIR generates replication stress. Ablation of BLM helicase activity in APBs abolishes telomere synthesis but causes multiple chromosome bridges between telomeres, revealing a function of BLM in processing inter-telomere BIR intermediates. Interestingly, the accumulation of BLM in APBs requires its own helicase activity and POLD3, suggesting that BIR triggers a feedforward loop to further recruit BLM. Enhancing BIR induces PIAS4-mediated TRF2 SUMOylation, and PIAS4 loss deprives APBs of repair proteins and compromises ALT telomere synthesis. Thus, a BLM-driven and PIAS4-mediated feedforward loop operates in APBs to perpetuate BIR, providing a critical mechanism to extend ALT telomeres.
Collapse
Affiliation(s)
- Jia-Min Zhang
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Marie-Michelle Genois
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Jian Ouyang
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Li Lan
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA; Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Lee Zou
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA; Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
| |
Collapse
|
25
|
Shen M, Young A, Autexier C. PCNA, a focus on replication stress and the alternative lengthening of telomeres pathway. DNA Repair (Amst) 2021; 100:103055. [PMID: 33581499 DOI: 10.1016/j.dnarep.2021.103055] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 01/25/2021] [Indexed: 12/16/2022]
Abstract
The maintenance of telomeres, which are specialized stretches of DNA found at the ends of linear chromosomes, is a crucial step for the immortalization of cancer cells. Approximately 10-15 % of cancer cells use a homologous recombination-based mechanism known as the Alternative Lengthening of Telomeres (ALT) pathway to maintain their telomeres. Telomeres in general pose a challenge to DNA replication owing to their repetitive nature and potential for forming secondary structures. Telomeres in ALT+ cells especially are subject to elevated levels of replication stress compared to telomeres that are maintained by the enzyme telomerase, in part due to the incorporation of telomeric variant repeats at ALT+ telomeres, their on average longer lengths, and their modified chromatin states. Many DNA metabolic strategies exist to counter replication stress and to protect stalled replication forks. The role of proliferating cell nuclear antigen (PCNA) as a platform for recruiting protein partners that participate in several of these DNA replication and repair pathways has been well-documented. We propose that many of these pathways may be active at ALT+ telomeres, either to facilitate DNA replication, to manage replication stress, or during telomere extension. Here, we summarize recent evidence detailing the role of PCNA in pathways including DNA secondary structure resolution, DNA damage bypass, replication fork restart, and DNA damage synthesis. We propose that an examination of PCNA and its post-translational modifications (PTMs) may offer a unique lens by which we might gain insight into the DNA metabolic landscape that is distinctively present at ALT+ telomeres.
Collapse
Affiliation(s)
- Michelle Shen
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, H3A 0C7, Canada; Jewish General Hospital, Lady Davis Institute, Montreal, Quebec, H3T 1E2, Canada
| | - Adrian Young
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, H3A 0C7, Canada; Jewish General Hospital, Lady Davis Institute, Montreal, Quebec, H3T 1E2, Canada
| | - Chantal Autexier
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, H3A 0C7, Canada; Jewish General Hospital, Lady Davis Institute, Montreal, Quebec, H3T 1E2, Canada.
| |
Collapse
|
26
|
[Are telomeres and telomerase still relevant targets in oncology?]. Bull Cancer 2020; 108:30-38. [PMID: 33256968 DOI: 10.1016/j.bulcan.2020.10.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 10/18/2020] [Indexed: 02/07/2023]
|
27
|
Photosensitizers Based on G-Quadruplex Ligand for Cancer Photodynamic Therapy. Genes (Basel) 2020; 11:genes11111340. [PMID: 33198362 PMCID: PMC7697063 DOI: 10.3390/genes11111340] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/09/2020] [Accepted: 11/10/2020] [Indexed: 12/12/2022] Open
Abstract
G-quadruplex (G4) is the non-canonical secondary structure of DNA and RNA formed by guanine-rich sequences. G4-forming sequences are abundantly located in telomeric regions and in the promoter and untranslated regions (UTR) of cancer-related genes, such as RAS and MYC. Extensive research has suggested that G4 is a potential molecular target for cancer therapy. Here, we reviewed G4 ligands as photosensitizers for cancer photodynamic therapy (PDT), which is a minimally invasive therapeutic approach. The photosensitizers, such as porphyrins, were found to be highly toxic against cancer cells via the generation of reactive oxidative species (ROS) upon photo-irradiation. Several porphyrin derivatives and analogs, such as phthalocyanines, which can generate ROS upon photo-irradiation, have been reported to act as G4 ligands. Therefore, they have been implicated as promising photosensitizers that can selectively break down cancer-related DNA and RNA forming G4. In this review, we majorly focused on the potential application of G4 ligands as photosensitizers, which would provide a novel strategy for PDT, especially molecularly targeted PDT (mtPDT).
Collapse
|
28
|
Bryan TM. G-Quadruplexes at Telomeres: Friend or Foe? Molecules 2020; 25:molecules25163686. [PMID: 32823549 PMCID: PMC7464828 DOI: 10.3390/molecules25163686] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/09/2020] [Accepted: 08/10/2020] [Indexed: 12/28/2022] Open
Abstract
Telomeres are DNA-protein complexes that cap and protect the ends of linear chromosomes. In almost all species, telomeric DNA has a G/C strand bias, and the short tandem repeats of the G-rich strand have the capacity to form into secondary structures in vitro, such as four-stranded G-quadruplexes. This has long prompted speculation that G-quadruplexes play a positive role in telomere biology, resulting in selection for G-rich tandem telomere repeats during evolution. There is some evidence that G-quadruplexes at telomeres may play a protective capping role, at least in yeast, and that they may positively affect telomere maintenance by either the enzyme telomerase or by recombination-based mechanisms. On the other hand, G-quadruplex formation in telomeric DNA, as elsewhere in the genome, can form an impediment to DNA replication and a source of genome instability. This review summarizes recent evidence for the in vivo existence of G-quadruplexes at telomeres, with a focus on human telomeres, and highlights some of the many unanswered questions regarding the location, form, and functions of these structures.
Collapse
Affiliation(s)
- Tracy M Bryan
- Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| |
Collapse
|
29
|
Abstract
Several decades elapsed between the first descriptions of G-quadruplex nucleic acid structures (G4s) assembled in vitro and the emergence of experimental findings indicating that such structures can form and function in living systems. A large body of evidence now supports roles for G4s in many aspects of nucleic acid biology, spanning processes from transcription and chromatin structure, mRNA processing, protein translation, DNA replication and genome stability, and telomere and mitochondrial function. Nonetheless, it must be acknowledged that some of this evidence is tentative, which is not surprising given the technical challenges associated with demonstrating G4s in biology. Here I provide an overview of evidence for G4 biology, focusing particularly on the many potential pitfalls that can be encountered in its investigation, and briefly discuss some of broader biological processes that may be impacted by G4s including cancer.
Collapse
Affiliation(s)
- F. Brad Johnson
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States
| |
Collapse
|
30
|
Bajaj S, Kumar MS, Peters GJ, Mayur YC. Targeting telomerase for its advent in cancer therapeutics. Med Res Rev 2020; 40:1871-1919. [PMID: 32391613 DOI: 10.1002/med.21674] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 04/19/2020] [Accepted: 04/21/2020] [Indexed: 12/24/2022]
Abstract
Telomerase has emerged as an important primary target in anticancer therapy. It is a distinctive reverse transcriptase enzyme, which extends the length of telomere at the 3' chromosomal end, and uses telomerase reverse transcriptase (TERT) and telomerase RNA template-containing domains. Telomerase has a vital role and is a contributing factor in human health, mainly affecting cell aging and cell proliferation. Due to its unique feature, it ensures unrestricted cell proliferation in malignancy and plays a major role in cancer disease. The development of telomerase inhibitors with increased specificity and better pharmacokinetics is being considered to design and develop newer potent anticancer agents. Use of natural and synthetic compounds for the inhibition of telomerase activity can lead to an opening of new vistas in cancer treatment. This review details about the telomerase biochemistry, use of natural and synthetic compounds; vaccines and oncolytic virus in therapy that suppress the telomerase activity. We have discussed structure-activity relationships of various natural and synthetic telomerase inhibitors to help medicinal chemists and chemical biology researchers with a ready reference and updated status of their clinical trials. Suppression of human TERT (hTERT) activity through inhibition of hTERT promoter is an important approach for telomerase inhibition.
Collapse
Affiliation(s)
| | | | - G J Peters
- Department of Medical Oncology, VU University Medical Centre, Amsterdam, The Netherlands
| | - Y C Mayur
- SPPSPTM, SVKM's NMIMS, Mumbai, India
| |
Collapse
|