REVIEW | doi:10.20944/preprints202110.0407.v1
Subject: Life Sciences, Genetics Keywords: Cancer; Telomerase; hTERT; Telomere; Therapeutics; Genomic Integrity
Online: 27 October 2021 (12:39:22 CEST)
Telomerase is an enzyme which is culpable for the aliment and stability of telomeres. It also maintains the genomic integrity and chromosomal stability. The progressive shortening of telomeres may cause chromosomal instability and alternation in the telomerase. It may cause telomere attrition which can lead to oncogenic incidence in human. Cancer is a disease which is induced by genetic alternations in genes. The genetic mutation within the hTERT is a common type of scenario which is generally found above 90 percent of cancer. In cancer, the length of telomere and the activity of telomerase are very important for cancer cells to proliferate and also for the survival of tumors. Cancer cells regulate through several pathways to increase telomerase activity. There have been several advancements developed to inhibit the telomerase activity in cancer cell but the repercussion of those has demonstrated many adverse effects. Research on AAVs mediated telomerase gene therapy has demonstrated prominent outcomes in animal trials. Thus, it has the potential to bring significance shine in the telomerase cancer therapeutics. Here, in this review article we have analyzed studies related to telomerase gene therapeutics to cure cancer. We also have summarized the telomerase function and mechanism of action to cause cancer. Moreover, other current development in the clinical advances of telomerase inhibition in cancer is described.
BRIEF REPORT | doi:10.20944/preprints202103.0551.v1
Subject: Life Sciences, Biochemistry Keywords: Telomere attrition in covid19; telomerase and spike RNA
Online: 22 March 2021 (15:48:20 CET)
In this letter we investigate if SARS-CoV-2 RNA is involved in the increased ageing of alveolar cells. Our in silico study is explorative. With the results we are able to outline experiments with AEC2 repair of bleomycin damaged alveolar cells. If AEC2 repair capability is diminished by spike RNA then perhaps this result provides a first step on a route to treat immortal lung cancer cells.
ARTICLE | doi:10.20944/preprints202301.0374.v1
Subject: Medicine & Pharmacology, Other Keywords: Telomerase; leukocyte telomere length; vitamin D; aging; serum levels; geroscience
Online: 22 January 2023 (03:36:34 CET)
Background: Shorter leukocyte telomere length (LTL) is observed in multiple age-related diseases, which are also associated with vitamin D deficiency (i.e., osteosarcopenia, neurocognitive disorders, cancer, osteoarthritis, etc.), which suggests a close association. In this study, we examined the relationship between vitamin D levels and LTL in older participants of the UK Biobank. Methods: Data were collected from the UK Biobank. Participants aged 60 and older (n=148,321) were included. Baseline LTL was measured using a multiplex qPCR technique and expressed as the ratio of the telomere amplification product (T) to that of a single-copy gene (S) (T/S ratio). Se-rum 25-hydroxyvitamin D (25OHD) was stratified by z score and linked to LTL in a linear regression model adjusting for covariates. Results: Compared to the medium level, a low (in the range of 16.6 nmol/L, 29.7 nmol/L) or extremely low (≤ 16.6 nmol/L) level of serum 25OHD was associated with shorter LTL: 0.018 SD (standardized β= -0.018, 95% CI -0.033 to -0.003, P=0.022) and 0.048 SD (standardized β= -0.048, 95% CI -0.083 to -0.014, P=0.006), respectively. Additionally, the high serum 25OHD groups (> 95.9 nmol/L) had 0.038 SD (standardized β= -0.038, 95% CI -0.072 to -0.004, P=0.030) shorter mean LTL than the group with medium 25OHD levels. The associations above were adjusted for multiple variables. Conclusion: In this population-based study, we identified an inverted U-shape relationship between LTL and vitamin D status. Whether high or low vitamin D-associated shorter LTL is mechanistically related to age-related conditions remains to be elucidated.
REVIEW | doi:10.20944/preprints202211.0255.v1
Subject: Medicine & Pharmacology, Other Keywords: Anti-aging therapy; lipofuscin; SENS; oncolytic vector; telomerase; TFEB; intracellular microbe
Online: 14 November 2022 (11:05:02 CET)
Aging kills 100,000 people a day - more than any other cause of death combined. The exact causes of aging have been much discussed, but the most pressing issue with regard to aging appears to me to be lipofuscin accumulation. That is, the accumulation of indigestible cellular garbage that needs to be removed from our cells, then the body. In this piece, I will explain why I think “getting rid of the garbage” should be at least one of our main goals with regard to longevity research for now.
ARTICLE | doi:10.20944/preprints202208.0364.v1
Subject: Biology, Other Keywords: TMPyP4 1; Thymoquinone 2; cell viability 3; cell adhesion 4; telomerase
Online: 19 August 2022 (10:46:07 CEST)
G‐quadruplexes (G4) are structures formed at the ends of the telomere, these are rich in guanines and were stabilized by molecules that bind to specific sites. TMPyP4 and Thymoquinone (TQ) are small molecules that bind to the G4, they have drawn attention because of their role as telomerase inhibitors. The aim of this study was to evaluate the effects of telomerase inhibitors on cellular proliferation, senescence, and death. Two cell lines LC‐HK2 (NSCLC) and RPE‐1 were treated with TMPyP4 (5μM) and TQ (10μM). Both inhibitors were effective in decreasing telomerase activity. TMPyP4 increased the percentage of cells with membrane damage associated with cell death and decreased the frequency of cells in the S‐phase. TMPyP4 changed the cell adhesion ability and modified the pattern of focal adhesion. TQ acted in a dose‐dependent manner, increasing the frequency of senescent cells, and inducing cell cycle arrest in the G1. In conclusion, the effects of both drugs on LC-HK2 and RPE-1 cell lines were different although both are telomerase inhibitors, because TMPyP4 decreased proteins of cell adhesion and TQ induces a decrease in cell viability.
ARTICLE | doi:10.20944/preprints202007.0268.v1
Subject: Medicine & Pharmacology, Pathology & Pathobiology Keywords: cardiovascular disease; inflammation; aging; senectome, telomerase; alternative splicing; relaxation response; microRNA
Online: 12 July 2020 (16:57:10 CEST)
Mental stress represents a pivotal factor in cardiovascular diseases. The mechanism by which stress produces its deleterious effects is still under study but one of the most explored pathway is cell senescence. In this scenario, circulating microRNAs appear to be mobile regulatory elements of the telomerase activity and alternative splicing within the ”senectome” network. Anti-stress techniques seem to be able to slow-down aging process. As we have recently verified how the practice of Relaxation Response (RR), counteracting psychological stress, determines favorable changes of some inflammatory genes expression, of some neurotransmitters, hormones, cytokines and inflammatory circulating microRNAs, we aimed to verify a possible change even in serum levels of 4 senectome micro-RNAs (SE-miRNAs -20, -30, -410, -515), testing the activity of telomerase in peripheral blood mononuclear cells-PBMCs. We analyzed also alternative splicing microRNAs 134 and 183. According to our data, miRNA-20 and -30 levels and PBMCs-telomerase activity increase during the RR while -410 and -515 levels decrease. Moreover, during the RR sessions both miRNA-134 and -183 decrease. The mediators considered in this work seem to vary rapidly according to a (stress)-relaxation condition showing that psychic activity should be part of the study of aging factors.
ARTICLE | doi:10.20944/preprints201805.0234.v1
Subject: Biology, Other Keywords: non-coding RNA; telomerase RNA; secondary structure; synteny; homology search; yeast
Online: 16 May 2018 (11:58:28 CEST)
The telomerase RNA in yeasts is large, usually >1000 nt, and contains functional elements that have been extensively studied experimentally in several disparate species. Nevertheless, they are very difficult to detect by homology-based methods and so far have escaped annotation in the majority of the genomes of Saccharomycotina. This is a consequence of sequences that evolve rapidly at nucleotide level, are subject to large variations in size, and are highly plastic with respect to their secondary structures. Here we report on a survey that was aimed at closing this gap in RNA annotation. Despite considerable efforts and the combination of a variety of different methods, it was only partially successful. While 27 new telomerase RNAs were identified, we had to restrict our efforts to the subgroup Saccharomycetacea because even this narrow subgroup was diverse enough to require different search models for different phylogenetic subgroups. More distant branches of the Saccharomycotina still remain without annotated telomerase RNA.
ARTICLE | doi:10.20944/preprints202211.0074.v1
Subject: Life Sciences, Cell & Developmental Biology Keywords: telomerase; TERT promoter; DNMT3B; pluripotent stem cells; characterization; epigenetic; meth-ylation; physiological oxygen; DNA methyltransferase
Online: 3 November 2022 (09:16:20 CET)
Telomere repeats at the ends of human chromosomes protect chromosomes from degradation, and telomerase has a prominent role in telomere maintenance. Telomerase also affects cell proliferation, DNA replication, differentiation, and tumourigenesis. TERT (telomerase reverse transcriptase enzyme) is the catalytic subunit of telomerase and is critical for enzyme activity. TERT promoter mutations and promoter methylation are strongly associated with increased telomerase activation in cancer cells. Notably, TERT and telomerase are downregulated in stem cells during their differentiation. Therefore, the link between differentiation and telomerase provides a valuable tool for studying the epigenetic regulation of TERT enzyme. Oxygen tension affects several cellular behaviours including proliferation, metabolic activity, stemness, and differentiation. The role of oxygen tension in driving promoter modifications of the TERT gene in embryonic stem cells (ESCs) is poorly understood either in vitro or in vivo. We adopted a monolayer ESCs differentiation model to explore the role of low, physiological, oxygen (physoxia) in the epigenetic regulation of telomerase and associated genes, including TERT, DNMTs, and HDACs. Cells were cultured in either air, a 2% O2 incubator, or a 2% O2 oxygen workstation to provide a fully defined 2% O2 environment. Pre-gassed media (pre-conditioned to 2% O2 in a HypoxyCool unit) was used in all 2% O2 experimentation. As anticipated, physoxia culture increased the proliferation rate and stemness of ESCs and a slower onset of differentiation in physoxia was evident. Further, downregulated TERT expression was correlated to reduced telomerase activity during differentiation. TERT expression and telomerase activity remained significantly elevated in physoxia during differentiation. A substantial increase in TERT promoter methylation levels was noted during differentiation. Chemical inhibition of DNMT3B reduced TERT promoter methylation and was associated with increased TERT gene and telomerase activity during differentiation. DNMT3B CHiP demonstrated that downregulated TERT expression and increased proximal promoter methylation were associated with DNMT3B binding to the promoter. In conclusion, we have demonstrated that DNMT3B can directly bind TERT promoter, change its methylation levels, and contribute to regulation of telomerase activity.
REVIEW | doi:10.20944/preprints202011.0029.v1
Subject: Life Sciences, Biochemistry Keywords: Oxadiazoles; Bioactive heterocyclics; anticancer agents; Telomerase; Carbonic anhydrase; Histone deacetylase; Kinases; Tubulin; DNA; G-quadruplex.
Online: 2 November 2020 (11:18:22 CET)
Nowadays, an increasing number of heterocyclic-based drugs found application in medicinal chemistry and, in particular, as anticancer agents. In this context, oxadiazoles, five-membered aromatic rings, emerged for their interesting biological properties. Modification of oxadiazole scaffolds represents a valid strategy to increase their anticancer activity, especially on 1,2,4 and 1,3,4 regioisomers. In the last years, an increasing number of oxadiazole derivatives, with remarkable cytotoxicity for several tumor lines, were identified. Structural modifications, that ensure higher cytotoxicity towards malignant cells, represent a solid starting point in the development of novel oxadiazoles-based drugs. To increase the specificity of this strategy, outstanding oxadiazole scaffolds have been designed to selectively interact with biological targets, including enzymes, globular proteins and nucleic acids, showing more promising antitumor effects. In the present work, we aim to provide a comprehensive overview of the anticancer activity of these heterocycles, describing their effect on different targets and highlighting how their structural versatility has been exploited to modulate their biological properties.
REVIEW | doi:10.20944/preprints201611.0060.v1
Subject: Materials Science, Biomaterials Keywords: cell-penetrating peptides (CPPs); reverse-transcriptase-subunit of telomerase (hTERT); GV1001; heat shock protein 90
Online: 11 November 2016 (09:59:30 CET)
Cell-penetrating peptides (CPPs), a group of small peptides capable of promoting the transport of molecular cargo across the plasma membrane, have become important tools in promoting the cellular uptake of exogenously delivered macromolecules. GV1001, a peptide derived from a reverse-transcriptase subunit of telomerase (hTERT) and developed as a vaccine against various cancers, reportedly has unexpected CPP properties. Unlike typical CPPs, such as the HIV-1 TAT peptide, GV1001 enabled the cytosolic delivery of macromolecules such as proteins, DNA and siRNA via extracellular heat shock protein 90 (eHSP90) and 70 (eHSP70) complexes. The eHSP-GV1001 interaction may have biological effects in addition to its cytosolic delivery function. GV1001 was originally designed as a MHC class II-binding cancer epitope, but its CPP properties may contribute to its strong anti-cancer immune response relative to other telomerase peptide-based vaccines. Cell signaling via eHSP-GV1001 binding may lead to unexpected biological effects, such as direct anticancer or antiviral effects. In this review, we focus on the CPP effects of GV1001 bound to eHSP90 and ehsp70.
ARTICLE | doi:10.20944/preprints202104.0020.v1
Subject: Life Sciences, Biochemistry Keywords: hepatitis C virus; hepatocellular carcinoma; immunotherapy; multi-component DNA vaccine; nucleocapsid (core) protein; telomerase reverse transcriptase; eukaryotic expression; CD4+ and CD8+ T cell response; immune suppression; assays of reporter expression; induction of type I interferons
Online: 1 April 2021 (13:18:59 CEST)
Chronic HCV infection and associated liver cancer impose a heavy burden on the healthcare system. Direct acting antivirals eliminate HCV, unless it is drug resistant, and partially reverse liver disease, but they cannot cure HCV-related cancer. Possible remedy could be a multi-component immunotherapeutic vaccine targeting both HCV-infected and malignant cells, also those not infected with HCV. To meet this need we developed a two-component DNA vaccine based on the highly conserved core protein of HCV to target HCV-infected cells, and a renowned tumor associated antigen telomerase reverse transcriptase (TERT) based on the rat TERT, to target malignant cells. Their synthetic genes were expression-optimized, and HCV core was truncated after aa 152 (Core152opt) to delete the domain interfering with immunogenicity. Core152opt and TERT DNA were highly immunogenic in BALB/c mice, inducing IFN-γ/IL-2/TNF-α response of CD4+ and CD8+ T cells. Also, DNA-immunization with TERT enhanced cellular immune response against luciferase encoded by a co-delivered plasmid (Luc DNA). However, DNA-immunization with Core152opt and TERT mix resulted in abrogation of immune response against both components. A loss of bioluminescent signal after co-delivery of TERT and Luc DNA into mice indicated that TERT affects the in vivo expression of luciferase directed by the immediate early cytomegalovirus and interferon-β promoters. Panel of mutant TERT variants was created and tested for their expression effects. TERT with deleted N-terminal nucleoli localization signal and mutations abrogating telomerase activity still suppressed the IFN-β driven Luc expression, while the inactivated reverse transcriptase domain of TERT and its analogue, enzymatically active HIV-1 reverse transcriptase, exerted only weak suppressive effects, implying that suppression relied on the presence of the full-length/nearly full-length TERT, but not its enzymatic activity. The effect(s) could be due to interference of the ectopically expressed xenogeneic rat TERT with biogenesis of mRNA, ribosomes and protein translation in murine cells, affecting the expression of immunogens. HCV core can aggravate this effect, leading to early apoptosis of co-expressing cells, preventing the induction of immune response.
REVIEW | doi:10.20944/preprints202209.0482.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: Telomerase reverse transcriptase; TERT; TERT promoter; TERTp; human papillomavirus; HPV; Epstein Barr virus (EBV); Kaposi sarcoma-associated herpesvirus; HHV-8; hepatitis B virus; HBV; hepatitis C virus; HCV; human T-cell leukemia virus-1; HTLV-1
Online: 30 September 2022 (10:11:58 CEST)
Human oncoviruses are able to subvert telomerase function in cancer cells through multiple strategies. The activity of the catalytic subunit of telomerase (TERT) is commonly enhanced in virus-related cancers. Viral oncoproteins, such as high-risk human papillomavirus (HPV) E6, Epstein-Barr virus (EBV) LMP1, Kaposi sarcoma-associated herpesvirus (HHV-8) LANA, hepatitis B virus (HBV) HBVx, hepatitis C virus (HCV) core protein and human T-cell leukemia virus-1 (HTLV-1) tax protein, interact with regulatory elements in the infected cells and contribute to the transcriptional activation of TERT gene. Specifically, viral oncoproteins have been shown to bind TERT promoter, to induce post-transcriptional alterations of TERT mRNA and to cause epigenetic modifications, which have important effects on the regulation of telomeric and extra-telomeric functions of the telomerase. Other viruses, such as herpesviruses, operate by integrating their genomes within the telomeres or by inducing alternative lengthening of telomeres (ALT) in non-ALT cells. In this review, we recapitulate recent findings on virus-telomerase/telomeres interplay and the importance of TERT-related oncogenic pathways activated by cancer causing viruses.