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Santiago JC, Westfall DH, Adams SV, Okuku F, Phipps W, Mullins JI. Variation within major internal repeats of KSHV in vivo. Virus Evol 2023; 9:vead034. [PMID: 37325087 PMCID: PMC10266750 DOI: 10.1093/ve/vead034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 05/09/2023] [Accepted: 05/18/2023] [Indexed: 06/17/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent of Kaposi's sarcoma (KS), yet the viral genetic factors that lead to the development of KS in KSHV-infected individuals have not been fully elucidated. Nearly, all previous analyses of KSHV genomic evolution and diversity have excluded the three major internal repeat regions: the two origins of lytic replication, internal repeats 1 and 2 (IR1 and IR2), and the latency-associated nuclear antigen (LANA) repeat domain (LANAr). These regions encode protein domains that are essential to the KSHV infection cycle but have been rarely sequenced due to their extended repetitive nature and high guanine and cytosine (GC) content. The limited data available suggest that their sequences and repeat lengths are more heterogeneous across individuals than in the remainder of the KSHV genome. To assess their diversity, the full-length IR1, IR2, and LANAr sequences, tagged with unique molecular identifiers (UMIs), were obtained by Pacific Biosciences' single-molecule real-time sequencing (SMRT-UMI) from twenty-four tumors and six matching oral swabs from sixteen adults in Uganda with advanced KS. Intra-host single-nucleotide variation involved an average of 0.16 per cent of base positions in the repeat regions compared to a nearly identical average of 0.17 per cent of base positions in the remainder of the genome. Tandem repeat unit (TRU) counts varied by only one from the intra-host consensus in a majority of individuals. Including the TRU indels, the average intra-host pairwise identity was 98.3 per cent for IR1, 99.6 per cent for IR2 and 98.9 per cent for LANAr. More individuals had mismatches and variable TRU counts in IR1 (twelve/sixteen) than in IR2 (two/sixteen). There were no open reading frames in the Kaposin coding sequence inside IR2 in at least fifty-five of ninety-six sequences. In summary, the KSHV major internal repeats, like the rest of the genome in individuals with KS, have low diversity. IR1 was the most variable among the repeats, and no intact Kaposin reading frames were present in IR2 of the majority of genomes sampled.
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Affiliation(s)
| | - Dylan H Westfall
- Department of Microbiology, University of Washington, 960 Republican St, Seattle, WA 98109-4325, USA
| | - Scott V Adams
- Global Oncology and Vaccine and Infectious Diseases Division,Fred Hutchinson Cancer Center, 1100 Eastlake Ave, Seattle, 98109-4487 WA, USA
| | - Fred Okuku
- Uganda Cancer Institute, Upper Mulago Hill Road, Kampala, Uganda
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2
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Recurrent repeat expansions in human cancer genomes. Nature 2023; 613:96-102. [PMID: 36517591 DOI: 10.1038/s41586-022-05515-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 11/02/2022] [Indexed: 12/16/2022]
Abstract
Expansion of a single repetitive DNA sequence, termed a tandem repeat (TR), is known to cause more than 50 diseases1,2. However, repeat expansions are often not explored beyond neurological and neurodegenerative disorders. In some cancers, mutations accumulate in short tracts of TRs, a phenomenon termed microsatellite instability; however, larger repeat expansions have not been systematically analysed in cancer3-8. Here we identified TR expansions in 2,622 cancer genomes spanning 29 cancer types. In seven cancer types, we found 160 recurrent repeat expansions (rREs), most of which (155/160) were subtype specific. We found that rREs were non-uniformly distributed in the genome with enrichment near candidate cis-regulatory elements, suggesting a potential role in gene regulation. One rRE, a GAAA-repeat expansion, located near a regulatory element in the first intron of UGT2B7 was detected in 34% of renal cell carcinoma samples and was validated by long-read DNA sequencing. Moreover, in preliminary experiments, treating cells that harbour this rRE with a GAAA-targeting molecule led to a dose-dependent decrease in cell proliferation. Overall, our results suggest that rREs may be an important but unexplored source of genetic variation in human cancer, and we provide a comprehensive catalogue for further study.
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3
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Shukla S, Lazarchuk P, Pavlova MN, Sidorova JM. Genome-wide survey of D/E repeats in human proteins uncovers their instability and aids in identifying their role in the chromatin regulator ATAD2. iScience 2022; 25:105464. [PMCID: PMC9672403 DOI: 10.1016/j.isci.2022.105464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 08/03/2022] [Accepted: 10/26/2022] [Indexed: 11/15/2022] Open
Abstract
D/E repeats are stretches of aspartic and/or glutamic acid residues found in over 150 human proteins. We examined genomic stability of D/E repeats and functional characteristics of D/E repeat-containing proteins vis-à-vis the proteins with poly-Q or poly-A repeats, which are known to undergo pathologic expansions. Mining of tumor sequencing data revealed that D/E repeat-coding regions are similar to those coding poly-Qs and poly-As in increased incidence of trinucleotide insertions/deletions but differ in types and incidence of substitutions. D/E repeat-containing proteins preferentially function in chromatin metabolism and are the more likely to be nuclear and interact with core histones, the longer their repeats are. One of the longest D/E repeats of unknown function is in ATAD2, a bromodomain family ATPase frequently overexpressed in tumors. We demonstrate that D/E repeat deletion in ATAD2 suppresses its binding to nascent and mature chromatin and to the constitutive pericentromeric heterochromatin, where ATAD2 represses satellite transcription. Many human proteins contain runs of aspartic/glutamic acid residues (D/E repeats) D/E repeats show increased incidence of in-frame insertions/deletions in tumors Nuclear and histone-interacting proteins often have long D/E repeats D/E repeat of the oncogene ATAD2 controls its binding to pericentric chromatin
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Affiliation(s)
- Shalabh Shukla
- Department of Laboratory Medicine and Pathology, University of Washington, 1959 NE Pacific St., Box 357705, Seattle, WA 98195, USA
| | - Pavlo Lazarchuk
- Department of Laboratory Medicine and Pathology, University of Washington, 1959 NE Pacific St., Box 357705, Seattle, WA 98195, USA
| | - Maria N. Pavlova
- Department of Laboratory Medicine and Pathology, University of Washington, 1959 NE Pacific St., Box 357705, Seattle, WA 98195, USA
| | - Julia M. Sidorova
- Department of Laboratory Medicine and Pathology, University of Washington, 1959 NE Pacific St., Box 357705, Seattle, WA 98195, USA
- Corresponding author
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Karamycheva S, Wolf YI, Persi E, Koonin EV, Makarova KS. Analysis of lineage-specific protein family variability in prokaryotes combined with evolutionary reconstructions. Biol Direct 2022; 17:22. [PMID: 36042479 PMCID: PMC9425974 DOI: 10.1186/s13062-022-00337-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 08/13/2022] [Indexed: 12/24/2022] Open
Abstract
Background Evolutionary rate is a key characteristic of gene families that is linked to the functional importance of the respective genes as well as specific biological functions of the proteins they encode. Accurate estimation of evolutionary rates is a challenging task that requires precise phylogenetic analysis. Here we present an easy to estimate protein family level measure of sequence variability based on alignment column homogeneity in multiple alignments of protein sequences from Clade-Specific Clusters of Orthologous Genes (csCOGs). Results We report genome-wide estimates of variability for 8 diverse groups of bacteria and archaea and investigate the connection between variability and various genomic and biological features. The variability estimates are based on homogeneity distributions across amino acid sequence alignments and can be obtained for multiple groups of genomes at minimal computational expense. About half of the variance in variability values can be explained by the analyzed features, with the greatest contribution coming from the extent of gene paralogy in the given csCOG. The correlation between variability and paralogy appears to originate, primarily, not from gene duplication, but from acquisition of distant paralogs and xenologs, introducing sequence variants that are more divergent than those that could have evolved in situ during the lifetime of the given group of organisms. Both high-variability and low-variability csCOGs were identified in all functional categories, but as expected, proteins encoded by integrated mobile elements as well as proteins involved in defense functions and cell motility are, on average, more variable than proteins with housekeeping functions. Additionally, using linear discriminant analysis, we found that variability and fraction of genomes carrying a given gene are the two variables that provide the best prediction of gene essentiality as compared to the results of transposon mutagenesis in Sulfolobus islandicus. Conclusions Variability, a measure of sequence diversity within an alignment relative to the overall diversity within a group of organisms, offers a convenient proxy for evolutionary rate estimates and is informative with respect to prediction of functional properties of proteins. In particular, variability is a strong predictor of gene essentiality for the respective organisms and indicative of sub- or neofunctionalization of paralogs. Supplementary Information The online version contains supplementary material available at 10.1186/s13062-022-00337-7.
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Affiliation(s)
- Svetlana Karamycheva
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD, 20894, USA
| | - Yuri I Wolf
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD, 20894, USA
| | - Erez Persi
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD, 20894, USA
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD, 20894, USA
| | - Kira S Makarova
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD, 20894, USA.
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Kaplun D, Starshin A, Sharko F, Gainova K, Filonova G, Zhigalova N, Mazur A, Prokhortchouk E, Zhenilo S. Kaiso Regulates DNA Methylation Homeostasis. Int J Mol Sci 2021; 22:7587. [PMID: 34299205 PMCID: PMC8307659 DOI: 10.3390/ijms22147587] [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: 05/31/2021] [Revised: 07/09/2021] [Accepted: 07/13/2021] [Indexed: 01/31/2023] Open
Abstract
Gain and loss of DNA methylation in cells is a dynamic process that tends to achieve an equilibrium. Many factors are involved in maintaining the balance between DNA methylation and demethylation. Previously, it was shown that methyl-DNA protein Kaiso may attract NCoR, SMRT repressive complexes affecting histone modifications. On the other hand, the deficiency of Kaiso resulted in reduced methylation of ICR in H19/Igf2 locus and Oct4 promoter in mouse embryonic fibroblasts. However, nothing is known about how Kaiso influences DNA methylation at the genome level. Here we show that deficiency of Kaiso led to whole-genome hypermethylation, using Kaiso deficient human renal cancer cell line obtained via CRISPR/CAS9 genome editing. However, Kaiso serves to protect genic regions, enhancers, and regions with a low level of histone modifications from demethylation. We detected hypomethylation of binding sites for Oct4 and Nanog in Kaiso deficient cells. Kaiso immunoprecipitated with de novo DNA methyltransferases DNMT3a/3b, but not with maintenance methyltransferase DNMT1. Thus, Kaiso may attract methyltransferases to surrounding regions and modulate genome methylation in renal cancer cells apart from being methyl DNA binding protein.
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Affiliation(s)
- Darya Kaplun
- Federal State Institution «Federal Research Centre «Fundamentals of Biotechnology» of the Russian Academy of Sciences», 119071 Moscow, Russia; (D.K.); (A.S.); (F.S.); (G.F.); (N.Z.); (A.M.)
- Institute of Gene Biology RAS, 119071 Moscow, Russia
| | - Alexey Starshin
- Federal State Institution «Federal Research Centre «Fundamentals of Biotechnology» of the Russian Academy of Sciences», 119071 Moscow, Russia; (D.K.); (A.S.); (F.S.); (G.F.); (N.Z.); (A.M.)
| | - Fedor Sharko
- Federal State Institution «Federal Research Centre «Fundamentals of Biotechnology» of the Russian Academy of Sciences», 119071 Moscow, Russia; (D.K.); (A.S.); (F.S.); (G.F.); (N.Z.); (A.M.)
| | - Kristina Gainova
- Centre for Strategic Planning of FMBA of Russia, 119071 Moscow, Russia;
| | - Galina Filonova
- Federal State Institution «Federal Research Centre «Fundamentals of Biotechnology» of the Russian Academy of Sciences», 119071 Moscow, Russia; (D.K.); (A.S.); (F.S.); (G.F.); (N.Z.); (A.M.)
| | - Nadezhda Zhigalova
- Federal State Institution «Federal Research Centre «Fundamentals of Biotechnology» of the Russian Academy of Sciences», 119071 Moscow, Russia; (D.K.); (A.S.); (F.S.); (G.F.); (N.Z.); (A.M.)
| | - Alexander Mazur
- Federal State Institution «Federal Research Centre «Fundamentals of Biotechnology» of the Russian Academy of Sciences», 119071 Moscow, Russia; (D.K.); (A.S.); (F.S.); (G.F.); (N.Z.); (A.M.)
- Institute of Gene Biology RAS, 119071 Moscow, Russia
| | - Egor Prokhortchouk
- Federal State Institution «Federal Research Centre «Fundamentals of Biotechnology» of the Russian Academy of Sciences», 119071 Moscow, Russia; (D.K.); (A.S.); (F.S.); (G.F.); (N.Z.); (A.M.)
- Institute of Gene Biology RAS, 119071 Moscow, Russia
| | - Svetlana Zhenilo
- Federal State Institution «Federal Research Centre «Fundamentals of Biotechnology» of the Russian Academy of Sciences», 119071 Moscow, Russia; (D.K.); (A.S.); (F.S.); (G.F.); (N.Z.); (A.M.)
- Institute of Gene Biology RAS, 119071 Moscow, Russia
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6
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Persi E, Wolf YI, Horn D, Ruppin E, Demichelis F, Gatenby RA, Gillies RJ, Koonin EV. Mutation-selection balance and compensatory mechanisms in tumour evolution. Nat Rev Genet 2020; 22:251-262. [PMID: 33257848 DOI: 10.1038/s41576-020-00299-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/16/2020] [Indexed: 12/11/2022]
Abstract
Intratumour heterogeneity and phenotypic plasticity, sustained by a range of somatic aberrations, as well as epigenetic and metabolic adaptations, are the principal mechanisms that enable cancers to resist treatment and survive under environmental stress. A comprehensive picture of the interplay between different somatic aberrations, from point mutations to whole-genome duplications, in tumour initiation and progression is lacking. We posit that different genomic aberrations generally exhibit a temporal order, shaped by a balance between the levels of mutations and selective pressures. Repeat instability emerges first, followed by larger aberrations, with compensatory effects leading to robust tumour fitness maintained throughout the tumour progression. A better understanding of the interplay between genetic aberrations, the microenvironment, and epigenetic and metabolic cellular states is essential for early detection and prevention of cancer as well as development of efficient therapeutic strategies.
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Affiliation(s)
- Erez Persi
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA.
| | - Yuri I Wolf
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - David Horn
- School of Physics and Astronomy, Raymond & Beverly Sackler Faculty of Exact Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Eytan Ruppin
- Cancer Data Science Lab, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Francesca Demichelis
- Department for Cellular, Computational and Integrative Biology, University of Trento, Trento, Italy.,Caryl and Israel Englander Institute for Precision Medicine, New York Presbyterian Hospital, Weill Cornell Medicine, New York, NY, USA
| | - Robert A Gatenby
- Integrated Mathematical Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA
| | - Robert J Gillies
- Department of Cancer Physiology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA.
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA.
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7
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Chavali S, Singh AK, Santhanam B, Babu MM. Amino acid homorepeats in proteins. Nat Rev Chem 2020; 4:420-434. [PMID: 37127972 DOI: 10.1038/s41570-020-0204-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2020] [Indexed: 12/16/2022]
Abstract
Amino acid homorepeats, or homorepeats, are polypeptide segments found in proteins that contain stretches of identical amino acid residues. Although abnormal homorepeat expansions are linked to pathologies such as neurodegenerative diseases, homorepeats are prevalent in eukaryotic proteomes, suggesting that they are important for normal physiology. In this Review, we discuss recent advances in our understanding of the biological functions of homorepeats, which range from facilitating subcellular protein localization to mediating interactions between proteins across diverse cellular pathways. We explore how the functional diversity of homorepeat-containing proteins could be linked to the ability of homorepeats to adopt different structural conformations, an ability influenced by repeat composition, repeat length and the nature of flanking sequences. We conclude by highlighting how an understanding of homorepeats will help us better characterize and develop therapeutics against the human diseases to which they contribute.
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Affiliation(s)
- Sreenivas Chavali
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK.
- Department of Biology, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, India.
| | - Anjali K Singh
- Department of Biology, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, India
| | - Balaji Santhanam
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK
- Department of Structural Biology and Center for Data Driven Discovery, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - M Madan Babu
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK.
- Department of Structural Biology and Center for Data Driven Discovery, St. Jude Children's Research Hospital, Memphis, TN, USA.
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8
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FOLR1 was up-regulated in cervical squamous cell carcinoma and correlated with the patients’ progression free survival. Pteridines 2020. [DOI: 10.1515/pteridines-2020-0014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
Objective The aim of the present work was to evaluate the folate-receptor 1 (FOLR1) expression in cervical squamous cell carcinoma and its clinical significance.
Methods
FOLR1 mRNA expression level was detected in the cancer genome atlas (TCGA) database for multiple carcinomas. The FOLR1 mRNA relative expression between tumor tissue and normal cervix tissue of the cervical squamous cell cancer patients was compared by the online data analysis tool of GEPIA. The overall survival (OS) and progression free survival (PFS) between the FOLR1 high and low expression groups were compared by the log-rank test. Thirty one cervical squamous cancer patients and 20 healthy controls were included in and tested for serum FOLR1 protein level detection. Eighty one cervical squamous cell cancer patients who received surgery were included for FOLR1 protein expression detected by immunohistochemistry assay (IHC). The correlation between FOLR1 protein expression and patients’ clinical features was analyzed.
Results
FOLR1 mRNA was up-regulated in tumor tissue compared to corresponding normal cervical tissue of cervical squamous cell carcinoma. Top 20 genes interacted with FOLR1 was identified through the network with the edges of 146. UBXN10 (r=0.668, P<0.01) and GBP6 (r-=0.606, P<0.01) were the top 2 genes that most correlated with FOLR1. The serum level of FR-α (FOLR1 coding protein) were 275.50±83.79 and 161.70±66.62 (ng/L) for the cervical cancer and healthy control subjects respectively with significant statistical difference (P<0.05). Using the serum FR-α as serological marker for cervical cancer detection, the diagnostic sensitivity, specificity and AUC were 80.0% (58.40% to 91.93%), 80.65% (63.72% to 90.81%) and 0.85(95%CI:0.74-0.96), respectively. Immunohistochemical assay indicated that of the 81 cancer tissue samples, 45 (55.6%) was FOLR1 protein positive. FOLR1 protein positive expression rate in FIGO stage Ⅲ/Ⅳ was significant higher than in the stage Ⅰ/Ⅱ with statistical difference (P<0.05). The progression free survival (PFS) was significant different between FOLR1 high and low expression group (HR=2.48, 95%CI:1.1-5.58, P=0.023). However, the overall survival (OS) was not statistical different between the two groups (HR=1.34, 95%CI:0.84-2.15, P=0.22).
Conclusion: FOLR1 was up-regulated in both serum and cancer tissue of cervical squamous cell carcinoma which may act as diagnostic and prognostic maker for cervical squamous cell cancer.
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9
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Khristich AN, Mirkin SM. On the wrong DNA track: Molecular mechanisms of repeat-mediated genome instability. J Biol Chem 2020; 295:4134-4170. [PMID: 32060097 PMCID: PMC7105313 DOI: 10.1074/jbc.rev119.007678] [Citation(s) in RCA: 160] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Expansions of simple tandem repeats are responsible for almost 50 human diseases, the majority of which are severe, degenerative, and not currently treatable or preventable. In this review, we first describe the molecular mechanisms of repeat-induced toxicity, which is the connecting link between repeat expansions and pathology. We then survey alternative DNA structures that are formed by expandable repeats and review the evidence that formation of these structures is at the core of repeat instability. Next, we describe the consequences of the presence of long structure-forming repeats at the molecular level: somatic and intergenerational instability, fragility, and repeat-induced mutagenesis. We discuss the reasons for gender bias in intergenerational repeat instability and the tissue specificity of somatic repeat instability. We also review the known pathways in which DNA replication, transcription, DNA repair, and chromatin state interact and thereby promote repeat instability. We then discuss possible reasons for the persistence of disease-causing DNA repeats in the genome. We describe evidence suggesting that these repeats are a payoff for the advantages of having abundant simple-sequence repeats for eukaryotic genome function and evolvability. Finally, we discuss two unresolved fundamental questions: (i) why does repeat behavior differ between model systems and human pedigrees, and (ii) can we use current knowledge on repeat instability mechanisms to cure repeat expansion diseases?
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Affiliation(s)
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, Massachusetts 02155.
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10
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Liu N, Guo XH, Liu JP, Cong YS. Role of telomerase in the tumour microenvironment. Clin Exp Pharmacol Physiol 2019; 47:357-364. [PMID: 31799699 DOI: 10.1111/1440-1681.13223] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 11/28/2019] [Accepted: 12/01/2019] [Indexed: 12/14/2022]
Abstract
Telomeres are specialized genomic structures that protect chromosomal ends to maintain genomic stability. Telomeric length is primarily regulated by the telomerase complex, essentially consisting of an RNA template (TERC), an enzymatic subunit (telomerase reverse transcriptase, TERT). In humans, telomerase activity is repressed during embryonic differentiation and is absent in most somatic cells. However, it is upregulated or reactivated in 80%-90% of the primary tumours in humans. The human TERT (hTERT) plays a pivotal role in cellular immortality and tumourigenesis. However, the molecular mechanisms of telomerase functioning in cancer have not been fully understood beyond the telomere maintenance. Several research groups, including ours, have demonstrated that hTERT possesses vital functions independent of its telomere maintenance, including angiogenesis, inflammation, cancer cell stemness, and epithelial-mesenchymal transformation (EMT). All these telomere-independent activities of hTERT may contribute to the regulation of the dynamics and homeostasis of the tumour microenvironment (TME), thereby promoting tumour growth and development. Cancer progression and metastasis largely depend upon the interactions between cancer cells and their microenvironment. In this review, the involvement of TERT in the tumour microenvironment and the underlying implications in cancer therapeutics have been summarized.
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Affiliation(s)
- Ning Liu
- College of Food Sciences and Technology, Shanghai Ocean University, Shanghai, China
| | - Xue-Hua Guo
- College of Food Sciences and Technology, Shanghai Ocean University, Shanghai, China
| | - Jun-Ping Liu
- Institute of Aging Research, Hangzhou Normal University School of Medicine, Hangzhou, China
| | - Yu-Sheng Cong
- Institute of Aging Research, Hangzhou Normal University School of Medicine, Hangzhou, China.,Key Laboratory of Aging and Cancer Biology of Zhejiang Province, Hangzhou, China
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