Telomerase Reverse Transcriptase Research Articles

Mutation analysis of the TERT gene in ovarian cancer patients of the Turkish population by next generation sequencing method.

Ovarian cancer (OC) ranks seventh among malignant tumors worldwide. As one of the most common gynecological malignancies, ovarian cancer has the second-highest mortality rate, after cervical and uterine cancer. Next-Generation Sequencing (NGS) technology has enhanced multi-gene panel analysis and its clinical utility for identifying cancer-causing gene mutations. This study aimed to determine the presence of significant and nonsense mutations in telomerase reverse transcriptase (TERT), alpha-thalassemia/mental retardation, X-linked (ATRX), O-6-methylguanine-DNA methyltransferase (MGMT), and isocitrate dehydrogenase 1 and 2 (IDH1/IDH2) genes using the Next-Generation Sequencing (NGS) method. A cohort of 33 patients diagnosed with ovarian cancer was included in this investigation, and peripheral blood samples were collected from all participants. Significant and nonsense mutations in TERT, ATRX, MGMT, IDH1, and IDH2 genes were detected using the Next-Generation Sequencing method. Bioinformatics analysis was conducted using the QIAGEN Clinical Insight system. Twenty-four patients exhibited seven different TERT mutations, occurring in both exonic and intronic regions. One patient displayed a c.699-3delC deletion in the intronic region of the IDH1 gene, and the c.532G > A (p.V178I) mutation observed in three patients was assessed as potentially harmful. Additionally, novel mutations c.881A > G and c.995A > G were observed in the ATRX gene. The heterozygous novel mutation identified in the ATRX gene was confirmed through Sanger sequencing. These mutations were not previously associated with ovarian cancer and are considered novel candidate markers for ovarian cancer susceptibility. Confirmation of these results through larger cohort studies or functional investigations will contribute to a better understanding of the molecular mechanisms underlying ovarian cancer.

Reactivation of telomerase reverse transcriptase expression in cancer: the role of TERT promoter mutations.

Telomerase activity and telomere elongation are essential conditions for the unlimited proliferation of neoplastic cells. Point mutations in the core promoter region of the telomerase reverse transcriptase (TERT) gene have been found to occur at high frequencies in several tumour types and considered a primary cause of telomerase reactivation in cancer cells. These mutations promote TERT gene expression by multiple mechanisms, including the generation of novel binding sites for nuclear transcription factors, displacement of negative regulators from DNA G-quadruplexes, recruitment of epigenetic activators and disruption of long-range interactions between TERT locus and telomeres. Furthermore, TERT promoter mutations cooperate with TPP1 promoter nucleotide changes to lengthen telomeres and with mutated BRAF and FGFR3 oncoproteins to enhance oncogenic signalling in cancer cells. TERT promoter mutations have been recognized as an early marker of tumour development or a major indicator of poor outcome and reduced patients survival in several cancer types. In this review, we summarize recent findings on the role of TERT promoter mutations, telomerase expression and telomeres elongation in cancer development, their clinical significance and therapeutic opportunities.

Antioxidant and anti-aging role of silk sericin in D-galactose induced mice model

The main purpose was to elucidate the potential anti-aging impact of sericin, due to its anti-oxidant potential in D-galactose induced mice model. To induce natural aging in mice, a solution of 0.9 % saline containing D-galactose (250 mg/kg b.w.) was injected intraperitoneally for a period of 60 days. In this experiment, 56 male mice were arbitrarily categorized into 8 groups (1: control; 2: D-Galactose (250 mg/kg b.w), Group 3: Sericin (150 mg/kg b.w), Group 4: Metformin (150 mg/kg), Group 5: sericin (P), Group 6; sericin (T), Group 7; Met (P), Group 8; Met (T). The level of Glutathione reductase (2.1 ± 0.2 µmol/L), CAT (0.5 ± 0.0 mmol/mL), Superoxide dismutase (65.4 ± 1.7 U/mL), GSHPx (69.2 ± 1.7 U/l), T3 (3.1 ± 0.7 ng/mL), IL-2 (68.8 ± 1.5 Pg/mL), IL-4 (71.4 ± 4.2 Pg/mL), IgG (0.6 ± 0.0 mg/mL) and IgM (0.6 ± 0.0 mg/mL) were significantly (P < 0.05) decreased whereas the cortisol (22.0 ± 1.5 µg/L), and total cholesterol (229.4 ± 4.2 mg/dL)) were significantly elevated in D-galactose-treated /aged mice. However, administration of sericin significantly reduced the level of oxidative stress in aged mice. Real-time qPCR data showed that the level of telomere length- gene TERT significantly downregulated (10.43 ± 0.1) in the D-Gal-treated mice with respect to control (21.97 ± 0.5). The highest significant upregulation was found in the TERT gene when D-Gal-induced aged mice were treated with sericin (24.74 ± 0.3). Our outcomes showed that sericin gradually recovered the organ indices, and improved the histological changes of the brain, kidney, and liver in D-Gal-induced aging mice. Therefore, concluded that sericin possesses anti-aging effect against D-Gal-induced aging by diminishing oxidative stress, restoring the immune system, and enhancing the antioxidant defense system.

Age-associated mortality is partially mediated by TERT promoter mutation status in differentiated thyroid carcinoma

Background Age at diagnosis (AAD) and telomerase reverse transcriptase (TERT) promoter mutations are prognostic factors in differentiated thyroid carcinoma (DTC), and the prevalence of the mutations increases with AAD. Considering this correlation, we investigated whether an interaction between AAD and the mutations is present and whether the mutation mediates the effect of AAD on the mortality rate in DTC. Methods The study included 393 patients with DTC who were followed-up after thyroidectomy at a single medical center in Korea from 1994 to 2004. Multivariable Cox regression was used to investigate the interaction of AAD and TERT promoter mutation. Mediation analysis was conducted using a regression-based causal mediation model. Results The age-associated mortality rate increased progressively in all DTC patients and wild-type TERT group (WT-TERT) with a linear trend (p &lt; 0.001) contrary to mutant TERT group (M-TERT) (p = 0.301). Kaplan-Meier curves declined progressively with increasing AAD in the entire group, but the change was without significance in M-TERT. The effect of AAD on mortality was not significant (adjusted HR: 1.07, 95% CI 0.38–3.05) in M-TERT. An interaction between AAD and TERT promoter mutation (p = 0.005) was found in a multivariable Cox regression. TERT promoter mutations mediated the effect of AAD on the mortality rate by 36% in DTC in a mediation analysis. Conclusions Considering the mediation of TERT promoter mutation on the effect of AAD on mortality, inclusion of TERT promoter mutation in a stage classification to achieve further individualized prediction in DTC is necessary.

BIOM-31. TARGETED DNA SEQUENCING OF RECURRENT GLIOBLASTOMA IDENTIFIES MOLECULAR FACTORS ASSOCIATED WITH CLINICAL OUTCOMES

Abstract PURPOSE The goal of our project was to define the molecular features of recurrent glioblastoma (rGBM) and their prognostic significance. METHODS We retrospectively reviewed 121 consecutive glioblastoma patients who underwent re-resection at a single institution from 2016-2021. Primary treatment in all patients included maximal safe resection followed by radiotherapy with concurrent and adjuvant temozolomide (TMZ). Capture-based targeted DNA sequencing for point mutations and copy number analysis was performed on all re-resection samples. Overall (OS) and progression-free survival (PFS) from re-resection were analyzed with the Kaplan-Meier method and Cox regression analyses. RESULTS Median age at first recurrence was 57 years (range, 27-78) and follow up from re-resection was 11 months. Salvage therapy comprised re-irradiation (n = 52, 43%), temozolomide (TMZ) (n = 39, 32%), lomustine (n = 47, 39%), and/or bevacizumab (n = 22, 18%). Median OS and PFS were 12.1 and 4.4 months, respectively. Median tumor mutation burden (TMB) was 4 mut/Mb (range, 1-650), average unstable microsatellite sites (MSI) were 1.16% (range, 0-20), and MGMT was methylated in 71 (59%) patients. Longer OS was found after postoperative TMZ (19.1 vs. 9.1), KPS &amp;gt; 70 (13.6 vs. 11.1), and/or re-irradiation (12.6 vs. 8.4) (p&amp;lt; .05). On multivariate analysis, TMZ (HR 0.2, 0.079-0.48), re-irradiation (HR 0.27, 0.12-0.58), and mutations in PDGFRA (HR 0.24, 0.067-0.83) or PTEN (HR 2.3, 1.1-4.8) genes were associated with longer OS after re-resection (p&amp;lt; .05). Multivariate predictors of re-irradiation response included MSI &amp;gt;1.16 (HR 0.25, 0.084-0.75), and mutations in PDGFRA (HR 0.04, 0.005-0.33), TERT (HR 0.16, 0.033-0.78), or PIK3R1 (HR 0.18, 0.041-0.8) genes. In the 46 matched primary/recurrent tumors, 40 (87%%) had a change in a mutation and 9 (20%) demonstrated hypermutation, of which 4 (44%) had mismatch repair deficiencies. CONCLUSIONS Our study outlines the molecular factors associated with survival and response to re-irradiation in rGBM as well as, the molecular differences between primary/recurrent samples.

PATH-46. A NOVEL POT1-TPD PRESENTATION: A GERMLINE POT1 MUTATION DISCOVERED IN A PATIENT WITH NEWLY DIAGNOSED POSTERIOR FOSSA EPENDYMOMA

Abstract INTRODUCTION POT1 tumor predisposition (POT1-TPD) is an autosomal dominant disorder characterized by increased lifetime malignancy risk. Melanoma, angiosarcoma and chronic lymphocytic leukemia are the most frequently reported malignancies. Other related cancers include gliomas. Protection of telomeres protein 1 is part of the shelterin protein complex to maintain/protect telomeres. Proposed mechanisms for oncogenesis with POT1 loss of function include telomere elongation and DNA damage response causing genomic instability. Ependymomas are a heterogeneous group comprising 12% of pediatric brain tumors and are locally aggressive with frequent recurrence. CASE PRESENTATION A healthy 3-year-old male presented with worsening vertigo, headaches, and emesis. Radiographic studies demonstrated a midline posterior fossa mass in the fourth ventricle. Following a gross total resection, pathology demonstrated a posterior fossa ependymoma, group A. Next generation sequencing (NGS) using our institution’s clinically validated panel, “CinCSeq”, demonstrated a POT1 splice site variant (c.1164-1G &amp;gt;A; variant allele frequency 46%). Paired germline testing via the molecular characterization initiative confirmed this variant as a heterozygote in the patient. Genetic testing confirmed a germline mutation in his mother who has a history of multiple nevi. He completed treatment with focal proton radiotherapy with no evidence of disease recurrence to date. DISCUSSION To our knowledge, this represents the first documented pediatric ependymoma with a familial, germline POT1 mutation. Somatic POT1 mutational frequency as determined by NGS in 60,000 solid tumors occurs at a rate of 2.94%. 45/60,000 were ependymomas with 1 non-benign POT1 mutation. Alterations of telomere maintenance have been reported in infratentorial ependymomas through increased human telomerase reverse transcriptase (hTERT) expression. This case sheds light on potential new mechanisms/predispositions for ependymoma development and the expanding phenotype of POT1-TPD. We recognize the POT1 mutation may have been discovered incidentally in this case. Further research into an association between POT1 and ependymomas is needed to advance our understanding.

Screening for a practical method to monitor the status of patients with metastatic bladder cancer at the circulating cell-gene level

Identifying a novel method to monitor metastatic bladder cancer status at the cell-gene level could lead to earlier appropriate therapeutic intervention and better outcomes. In this study, we evaluated a practical method to monitor the cancer status at the circulating cell-gene level before and after treatment in fourteen patients with metastatic bladder cancer who were indicated for systemic drug therapy. Patients were assessed via imaging before and after drug treatment, and cell-free DNA (cfDNA) analysis was performed to detect three parameters: cfDNA level, ERRB2 gene copy numbers, and telomerase reverse transcriptase (TERT) gene mutations. We hypothesized that decreased cfDNA levels, a normal copy number of ERB-B2 receptor tyrosine kinase 2 (ERBB2), and the absence of the TERT C228T mutation indicate cancer suppression. We found that a > 1.8-fold increase in cfDNA levels, increased copy number of ERBB2, or the existence of the TERT C228T mutation indicated disease progression. Stable cfDNA levels, normal ERBB2 copy number, and the absence of TERT C228T mutations indicate a stable cancer status. Collectively, our results show that the combination of cfDNA concentration, TERT mutation, and ERBB2 copy number may be useful for determining the efficacy of drug therapy in patients with metastatic bladder cancer.

VCAM-1 accelerates atrial remodeling in TERT-/- mice

Abstract Background Aging, an independent risk factor for AF, could significantly increase its morbidity and mortality. The mechanism of AF in the elderly population remains to be further elucidated. Atrial remodeling is considered to be an important mechanism of atrial fibrillation. Telomerase dysfunction and telomere shortening are important signs of aging, and the relationship and mechanism between telomerase dysfunction and atrial remodeling is not very clear. Purpose This study aims to explore the mechanism of atrial remodeling caused by telomerase dysfunction. Methods The atrial electrophysiology was used to detect refractory period (ERP) and atrial fibrillation inducibility, and the epicardial electrical mapping technique was used to detect the atrial conduction velocity, direction and conduction heterogeneity to evaluate the atrial electrical remodeling. HE and Masson staining were used to evaluate atrial structural remodeling. RNA-seq analysis screened out the differential genes and corresponding pathways in each model. Results Compared with wild-type (WT) mice, a third-generation of telomerase reverse-transcriptase knockout mice (F3 TERT-/-, hereafter as TERT-/-) showed a shortened atrial ERP, increased atrial fibrillation inducibility, slowed atrial conduction velocity,change in the direction of propagation, and increased atrial fibrosis, suggesting electrical and structural remodeling in TERT-/- mice. RNA-seq revealed significant changes in cell adhesion molecules (CAMs) of TERT-/- mice compared with the WT, among which vascular adhesion molecule (VCAM-1) changed most significantly. Then, TERT-/- mice were treated with anti-VCAM-1 neutralizing antibodies, atrial electrical and structural remodeling was partially relieved compared to untreated TERT-/- mice. RNA-seq and KEGG enrichment analysis were conducted on differential genes, which were mainly concentrated on extracellular matrix (ECM)-receptor interaction. Furthermore, we found that the extracellular matrix LAMC3, Collgen1 and myofibroblast marker α-SMA were reversed in TERT-/- mice treated with anti-VCAM-1 neutralizing antibodies compared with TERT-/- mice. Conclusion VCAM-1 could accelerate the production of extracellular matrix, and ultimately lead to atrial electricity and structural remodeling, and the occurrence of atrial fibrillation in TERT-/- mice.

HCV and HCC Tango-Deciphering the Intricate Dance of Disease: A Review Article.

Hepatitis C virus (HCV) is a major cause of hepatocellular carcinoma (HCC) accounting for around one-third of all HCC cases. Prolonged inflammation in chronic hepatitis C (CHC), maintained through a variety of pro- and anti-inflammatory mediators, is one of the aspects of carcinogenesis, followed by mitochondrial dysfunction and oxidative stress. Immune response dysfunction including the innate and adaptive immunity also plays a role in the development, as well as in the recurrence of HCC after treatment. Some of the tumor suppressor genes inhibited by the HCV proteins are p53, p73, and retinoblastoma 1. Mutations in the telomerase reverse transcriptase promoter and the oncogene catenin beta 1 are two more important carcinogenic signaling pathways in HCC associated with HCV. Furthermore, in HCV-related HCC, numerous tumor suppressor and seven oncogenic genes are dysregulated by epigenetic changes. Epigenetic regulation of gene expression is considered as a lasting "epigenetic memory", suggesting that HCV-induced changes persist and are associated with liver carcinogenesis even after cure. Epigenetic changes and immune response dysfunction are recognized targets for potential therapy of HCC.

A rare homozygous variant in TERT gene causing variable bone marrow failure, fragility fractures, rib anomalies and extremely short telomere lengths with high serum IgE.

By whole exome sequencing, we identified a homozygous c.2086 C→T (p.R696C) TERT mutation in patients who present with a spectrum of variable bone marrow failure (BMF), raccoon eyes, dystrophic nails, rib anomalies, fragility fractures (FFs), high IgE level, extremely short telomere lengths (TLs), and skewed numbers of cytotoxic T cells with B and NK cytopenia. Haploinsufficiency in the other family members resulted in short TL and osteopenia. These patients also had the lowest bone mineral density Z-score compared to other BMF-patients. Danazol/zoledronic acid improved the outcomes of BMF and FFs. This causative TERT variant has been observed in one family afflicted with dyskeratosis congenita (DC), and thus, we also define a second report and new phenotype related to the variant which should be suspected in severe cases of DC with co-existent BMF, FFs, high IgE level and rib anomalies.

A Recombinant Oncolytic Influenza Virus Carrying GV1001 Triggers an Antitumor Immune Response.

Oncolytic viruses are able to lyse tumor cells selectively in the liver without killing normal hepatocytes, in addition to activating the immune response. Oncolytic virus therapy is expected to revolutionize the treatment of liver cancer, including hepatocellular carcinoma (HCC), one of the most frequent and fatal malignancies. In this study, reverse genetics techniques were exploited to load NA fragments of the A/PuertoRico/8/34 virus (PR8) with GV1001 peptides derived from human telomerase reverse transcriptase. An in vitro assessment of the therapeutic effect of the recombinant oncolytic virus was followed by an in vivo study in mice with HCC. The recombinant virus was verified by sequencing of the recombinant viral gene sequence, and viral virulence was detected by hemagglutination assays and based on the 50% tissue culture infectious dose (TCID50). The morphological structure of the virus was observed by electron microscopy, and GV1001 peptide was localized by cellular immunofluorescence. The selective cytotoxicity of the recombinant oncolytic virus in vitro was demonstrated in cultured HCC cells and normal hepatocytes, as only the tumor cells were killed; the normal cells were not significantly altered. Consistent with the in vitro results, the recombinant oncolytic influenza virus significantly inhibited liver tumor growth in mice in vivo, in addition to inducing an antitumor immune response, including an increase in the number of CD4+ and CD8+ T lymphocytes and, in turn, improving survival. Our results suggest that oncolytic influenza virus carrying GV1001 is a promising immunotherapy in patients with HCC.

Comparative Analysis of the Prognostic Significance of IDH,TERT, EGFR and MGMT Status in Patients with Adult Non-H3-Altered Grade 4 Gliomas: A Prospective Cohort Study

IntroductionGliomas continue to have a dismal prognosis. A myriad of genetic alterations has been described in this subset of tumors over the last decades. The integrative interpretation of the biomarker constellation for individual patients remains unclear. This study aims to evaluate the impact of some known genetic factors as prognostic biomarkers in grade 4 gliomas. MethodsAdult non-H3-altered grade 4 gliomas who underwent maximal safe resection accompanied by adjuvant therapy were successively enrolled since January 2019 till January 2021. Patient data were documented preoperatively and during the follow-up visits. The genetic profiling of the tumors included IDH-1 and IDH-2 mutation, MGMT promoter methylation rate, EGFR gene amplification and TERT promoter (TERTp) mutation. ResultsMean Overall survival (OS) and Progression-free survival (PFS) were 14.45±5.13 months (3-24 months) and 10.66±4.87 months respectively. TERTp-mutant group had a significantly lower OS (10.9 vs 15.9) and PFS (6.9 vs 12.3) than TERTp wildtype group. In the TERT-mutant group, those with concomitant IDH wildtype tumor had higher OS and PFS, comparable to those with both TERTp and IDH wildtype tumors. In multivariate analysis, IDH mutation and TERTp wildtype status were predictive of longer OS and PFS. While IDH and absence of TERTp mutation were associated with KPS>80 across the follow-ups, their predictive values were inferior to preoperative KPS scores. ConclusionTERTp mutation and IDH-wildtype status were associated with worse OS and PFS and lower follow-up KPS score in surgically resected gliomas, while MGMT and EGFR status did not have considerable prognostic value in this study.

Novel, clinically relevant genomic patterns identified by comprehensive genomic profiling in ATRX-deficient IDH-wildtype adult high-grade gliomas

Glioblastomas are the most common IDH-wildtype adult high-grade gliomas, frequently harboring mutations in the TERT gene promoter (pTERT) and utilizing the subsequent telomerase overexpression for telomere length maintenance. However, some rare cases show loss of ATRX and use alternative mechanisms of telomere lengthening. In this study, we performed the first complex genomic analysis specifically concentrating on the latter subgroup. Comprehensive genomic profiling of 12 ATRX-deficient and 13 ATRX-intact IDH-wildtype adult high-grade gliomas revealed that ATRX and pTERT mutations are mutually exclusive. DNMT3A alterations were confined to ATRX-deficient, while PTEN mutations to ATRX-intact cases. RAS–MAPK pathway alterations, including NF1 mutations, were more characteristic in the ATRX-deficient group. Variants of genes related to homologous recombination repair showed different patterns of affected genes. Two ATRX-deficient tumors with high tumor mutational burden and mismatch repair deficiency were found. One of these contained a novel fusion involving the NTRK2 and LRRFIP2 genes, while the other showed loss of MSH2 and MSH6 without genetic alterations in the encoding genes suggesting an epigenetic background. Genetic characteristics of ATRX-deficient IDH-wildtype adult high-grade gliomas suggest that these tumors are particularly intriguing targets of potential future therapeutic interventions including immunotherapies combined with MAPK pathway inhibition and DNA repair inhibitors.

Association of TERT (rs2736098 and rs2736100) genetic variants with elevated risk of hepatocellular carcinoma: a retrospective case–control study

Hepatocellular carcinoma (HCC) is an inflammatory problematic issue with higher mortality among different ethnic populations. The telomerase reverse transcriptase (TERT) gene has an imperative role in the proliferation of various cancerous illnesses, particularly HCC. Moreover, the TERT (rs2736098 and rs2739100) variants were correlated with the HCC susceptibility and telomere shortening, but with unconvincing outcomes. The main purpose of this outward work is to assess the correlation between these significant variants within the TERT gene and the elevated risk of HCC with the aid of various computational bioinformatics tools. This study included 233 participants [125 cancer-free controls and 108 HCC patients] from the same locality. In addition, 81.5% of HCC patients were positive for HCV autoantibodies, while 73.1% of HCC patients were positive for cirrhotic liver. Genomic DNA of the TERT (rs2736098 and rs2736100) variants were characterized utilizing the PCR–RFLP method. Interestingly, the frequencies of TERT (rs2736098*A allele) and TERT (rs2736100*T allele) conferred a significant correlation with increased risk of HCC compared to healthy controls (p-value = 0.002, and 0.016, respectively). The TERT (rs2736098*A/A) genotype indicated a definite association with positive smoking and splenomegaly (p-value < 0.05), while the TERT (rs2736100*T/T) genotype observed a significant difference with higher levels of HCV autoantibodies (p-value = 0.009). In conclusion, this significant work confirmed the contribution of the TERT (rs2736098*A and rs2736100*T) alleles with elevated risk of HCC progression and telomere shortening among Egyptian subjects.

Molecular Markers Are Associated with Onset of Radioiodine Refractoriness in Patients with Papillary Thyroid Carcinoma.

The onset of radioiodine-refractory thyroid carcinoma (RR-TC) is a negative predictor of survival and has been linked to the presence of BRAFV600E mutations in papillary thyroid cancer. We aimed to identify further genetic alterations associated with RR-TC. Methods: We included 38 patients with papillary thyroid cancer who underwent radioiodine imaging and 18F-FDG PET/CT after total thyroidectomy. The molecular profile was assessed by next-generation sequencing. The time to the onset of RR-TC for different genetic alterations was compared using the log-rank test. Results: The median onset to RR-TC was 0.7 and 19.8 mo in patients with and without, respectively, telomerase reverse transcriptase promoter mutations (P = 0.02) and 1.7 and 19.8 mo in patients with and without, respectively, a tumor protein 53 mutation (P < 0.01). This association was not observed for BRAFV600E mutations (P = 0.49). Conclusion: Our data show a significant association between the onset of RR-TC and mutations in telomerase reverse transcriptase promoter and tumor protein 53, indicating the need for a more extensive diagnostic workup in these patients. Certain genetic changes put patients with thyroid cancer at risk of developing cancer spread that does not respond to radioiodine therapy.

Retraction: Zinc sulfate contributes to promote telomere length extension via increasing telomerase gene expression, telomerase activity and change in the TERT gene promoter CpG island methylation status of human adipose-derived mesenchymal stem cells.

Retraction: Zinc sulfate contributes to promote telomere length extension via increasing telomerase gene expression, telomerase activity and change in the TERT gene promoter CpG island methylation status of human adipose-derived mesenchymal stem cells.

Analysis of polymorphism and development of a molecular-genetic system for genotyp-ing by the telomerase reverse transcriptase (TERT) gene

This article explores the genetic variability of the gene that encodes telomerase reverse transcriptase (TERT), which plays a key role in maintaining telomere length and, as a result, genome stability in various eukaryotic species. The study employs a comprehensive approach that combines phylogenetic and bioinformatic analysis with molecular-genetic research methods. The research involved the screening of genetic databases to investigate TERT gene orthologues across organisms belonging to different systematic groups. The TERT gene, which is prevalent in a wide range of eukaryotic biological species, exhibits polymorphisms that have the potential to influence TERT enzyme function and, consequently, animal phenotypes. The primary focus of this study centers on the pig TERT gene, selected as a model organism due to its genetic similarity to humans and its importance as a productive agricultural species. The article explores the exon-intron structure of the TERT gene, analyzing the size of the corresponding transcript and protein product. Furthermore, it provides data on polymorphisms in the pig TERT gene, including missense and synonymous variants. The chromosomal localization of these polymorphisms is characterized and correlated with the domain structure of the TERT enzyme. For the evaluation of the impact of polymorphisms on the structural and functional properties of the TERT enzyme, a molecular-genetic system based on the PCR-RFLP method has been developed. This PCR-RFLP system serves as a basis for subsequent experimental analyses of missense and synonymous variants in population and association studies, allowing for an assessment of the prevalence of these polymorphisms and their significance for animal phenotypes. Given the significance of further laboratory investigation of the pig TERT gene, the developed PCR-RFLP system becomes necessary for the assessment of the functional implications of the polymorphisms within this gene and the potential identification of causative ones among them. The synergy of bioinformatics and molecular-genetic methods in this study lays the groundwork for future impactful research in this field. The presented study holds promise for marker-associated selection, as it opens the way for the use of the TERT gene as a marker in the genetic improvement of agricultural animal species.

TERT promoter mutations and gene amplification in endometrial cancer

ObjectiveTo assess the clinicopathologic, molecular profiles, and survival outcomes of patients with endometrial carcinomas (ECs) harboring telomerase reverse transcriptase (TERT) hotspot mutations or gene amplification. MethodsECs harboring somatic TERT promoter hotspot mutations or gene amplification (TERT-altered) were identified from 1944 ECs that underwent clinical tumor-normal sequencing from 08/2016–12/2021. Clinicopathologic variables, somatic mutation profiles, and survival outcomes of TERT-alt and TERT-wild-type EC were assessed. ResultsWe identified 66 TERT-altered ECs (43 TERT-mutated and 23 TERT-amplified), representing 3% of the unselected ECs across histologic subtypes. Most TERT-altered ECs were of copy number (CN)-high/TP53abn molecular subtype (n = 40, 60%), followed by microsatellite-unstable (MSI-H) or CN-low/no specific molecular profile (NSMP)(n = 13, 20% each). TERT-amplified and TERT-mutated ECs were molecularly distinct, with TERT-amplified ECs being more genomically instable and more frequently harboring TP53 and PPP2R1A alterations (q < 0.1). Compared to TERT-wild-type ECs, TERT-altered ECs were more commonly of CN-H/TP53abn molecular subtype (31% vs 57%, p = 0.001), serous histology (10% vs 26%, p = 0.004), and were significantly enriched for TP53, CDKN2A/B, and DROSHA somatic genetic alterations (q < 0.1). Median progression-free survival was 18.7 months (95% CI 11.8–not estimable [NE]) for patients with TERT-altered EC and 80.9 months (65.8-NE) for patients with TERT-wild-type EC (HR 0.33, 95% CI 0.21–0.51, p < 0.001). Similarly, median overall survival was 46.7 months (95% CI 30-NE) for TERT-altered EC patients and not reached for TERT-wild-type EC patients (HR 0.24, 95% CI 0.13–0.44, p < 0.001). ConclusionTERT-altered ECs, although rare, are enriched for CN-high/TP53abn tumors, TP53, CDKN2A/B and DROSHA somatic mutations, and independently predict worse survival outcomes.

Contribution of Telomere Length to Systemic Sclerosis Onset: A Mendelian Randomization Study.

Although previous studies have suggested a relationship between telomere shortening and systemic sclerosis (SSc), the association between these two traits remains poorly understood. The objective of this study was to assess the causal relationship between telomere length in leukocytes (LTL) and SSc using the two-sample Mendelian randomization approach, with the genome-wide association study data for both LTL and SSc. The results of inverse-variance weighted regression (OR = 0.716 [95% CI 0.528-0.970], p = 0.031) and the Mendelian randomization pleiotropy residual sum and outlier method (OR = 0.716 [95% CI 0.563-0.911], p = 0.035) indicate an association between telomere length and SSc. Specifically, longer genetically predicted LTL is associated with a reduced risk of SSc. Sensitivity tests highlight the significant roles of the variants rs10936599 and rs2736100 annotated to the TERC and TERT genes, respectively. Our findings suggest an influence of telomere length in leukocytes on the development of SSc.

Telomere dysfunction promotes cholangiocyte senescence and biliary fibrosis in Primary Sclerosing Cholangitis.

Cellular senescence and biliary fibrosis are prototypical features of obliterative cholangiopathies, such as Primary Sclerosing Cholangitis (PSC). Telomere dysfunction can lead to senescence either through telomere erosion or damaged telomeres. Our goal was to investigate a mechanistic relationship between telomere damage and biliary fibrosis in PSC. Telomere attrition was observed in the bile ducts of PSC patients along with a reduction in telomerase reverse transcriptase (TERT) expression compared to normal livers. Similarly, liver tissue from mice models of biliary fibrosis showed telomere attrition with increased damage at telomeres measured as telomere-associated foci (TAF). Cellular models of senescence induction increased the TAFs in cholangiocytes. This coincided with decreased TERT expression and increased senescence, which was rescued by modulating TERT levels. Epigenetic analysis revealed increased acquisition of repressive histone methylation at the TERT promoter which correlated with decreased TERT transcription. Cholangiocyte-selective deletion of TERT in mice exacerbated fibrosis whereas androgen therapy towards telomerase rescued liver fibrosis and liver function in genetic mouse model of PSC. Our results demonstrate a mechanistic role for telomere dysfunction in cellular senescence and fibrosis that characterize PSC. This suggests that PSC may be, in part, a telomere biology disorder, and identifies TERT as a potential therapeutic target.