RESUMEN
POT1 variants have been identified in familial melanoma (FM) as well as a number of other germline and somatic malignancies. The functional validation of variants identified from the screening of patients with melanoma gene susceptibility panels is key to understanding the clinical significance of identified variants. Here we report a novel, likely pathogenic POT1 missense variant (p.G95V) in FM and investigate its functional impact. We demonstrate loss of function owing to the inability of the mutant POT1 protein to bind telomeric DNA compared to its wild-type counterpart. This study provides important functional validation of a novel POT1 variant in FM.
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Shelterin serves critical roles in suppressing superfluous DNA damage repair pathways on telomeres. The junction between double-stranded telomeric tracts (dsTEL) and single-stranded telomeric overhang (ssTEL) is the most accessible region of the telomeric DNA. The shelterin complex contains dsTEL and ssTEL binding proteins and can protect this junction by bridging between the ssTEL and dsTEL tracts. To test this possibility, we monitored shelterin binding to telomeric DNA substrates with varying ssTEL and dsTEL lengths and quantified its impact on telomere accessibility using single-molecule fluorescence microscopy methods in vitro. We identified the first dsTEL repeat nearest to the junction as the preferred binding site for creating the shelterin bridge. Shelterin requires at least two ssTEL repeats while the POT1 subunit of shelterin that binds to ssTEL requires longer ssTEL tracts for stable binding to telomeres and effective protection of the junction region. The ability of POT1 to protect the junction is significantly enhanced by the 5'-phosphate at the junction. Collectively, our results show that shelterin enhances the binding stability of POT1 to ssTEL and provides more effective protection compared to POT1 alone by bridging single- and double-stranded telomeric tracts.
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The gene protection of telomere 1 (POT1) is involved in telomere maintenance and stability and plays a crucial role in the preservation of genomic stability. POT1 is considered a high-penetrance melanoma susceptibility gene; however, the number of cancer types associated with the pathogenic germline variants of POT1 is gradually increasing, including chronic lymphocytic leukemia (CLL), angiosarcomas, and gliomas, even though many associations are still elusive. Here, we reported a case of a 60-year-old man who showed early-onset multiple neoplasms, including multiple melanomas, gastrointestinal stromal tumor (GIST), and lung adenocarcinoma. Next-generation sequencing (NGS) analyses revealed a germline heterozygous pathogenic variant in the POT1 gene. Notably, GIST and lung adenocarcinoma were not previously reported in association with the POT1 germline variant. Lung cancer susceptibility syndrome is very rare and the actual knowledge is limited to a few genes although major genetic factors are unidentified. Recently, genome-wide association studies (GWAS) have pointed out an association between POT1 variants and lung cancer. This case report highlights the clinical relevance of POT1 alterations, particularly their potential involvement in lung cancer. It also suggests that POT1 testing may be warranted in patients with familial cancer syndrome, particularly those with a history of melanoma and other solid tumors.
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Telomere maintenance requires the extension of the G-rich telomeric repeat strand by telomerase and the fill-in synthesis of the C-rich strand by Polα/primase. At telomeres, Polα/primase is bound to Ctc1/Stn1/Ten1 (CST), a single-stranded DNA-binding complex. Like mutations in telomerase, mutations affecting CST-Polα/primase result in pathological telomere shortening and cause a telomere biology disorder, Coats plus (CP). We determined cryogenic electron microscopy structures of human CST bound to the shelterin heterodimer POT1/TPP1 that reveal how CST is recruited to telomeres by POT1. Our findings suggest that POT1 hinge phosphorylation is required for CST recruitment, and the complex is formed through conserved interactions involving several residues mutated in CP. Our structural and biochemical data suggest that phosphorylated POT1 holds CST-Polα/primase in an inactive, autoinhibited state until telomerase has extended the telomere ends. We propose that dephosphorylation of POT1 releases CST-Polα/primase into an active state that completes telomere replication through fill-in synthesis.
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ADN Polimerasa I , Complejo Shelterina , Proteínas de Unión a Telómeros , Telómero , Humanos , Microscopía por Crioelectrón , ADN Polimerasa I/metabolismo , ADN Primasa/metabolismo , ADN Primasa/genética , Modelos Moleculares , Fosforilación , Complejo Shelterina/metabolismo , Telomerasa/metabolismo , Telómero/metabolismo , Proteínas de Unión a Telómeros/metabolismoRESUMEN
Telomeres, potential biomarkers of aging, are known to shorten with continued cigarette smoke exposure. In order to further investigate this process and its impact on cellular stress and inflammation, we used an in vitro model with cigarette smoke extract (CSE) and observed the downregulation of telomere stabilizing TRF2 and POT1 genes after CSE treatment. hTERT is a subunit of telomerase and a well-known oncogenic marker, which is overexpressed in over 85% of cancers and may contribute to lung cancer development in smokers. We also observed an increase in hTERT and ISG15 expression levels after CSE treatment, as well as increased protein levels revealed by immunohistochemical staining in smokers' lung tissue samples compared to non-smokers. The effects of ISG15 overexpression were further studied by quantifying IFN-γ, an inflammatory protein induced by ISG15, which showed greater upregulation in smokers compared to non-smokers. Similar changes in gene expression patterns for TRF2, POT1, hTERT, and ISG15 were observed in blood and buccal swab samples from smokers compared to non-smokers. The results from this study provide insight into the mechanisms behind smoking causing telomere shortening and how this may contribute to the induction of inflammation and/or tumorigenesis, which may lead to comorbidities in smokers.
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Envejecimiento , Citocinas , Inflamación , Complejo Shelterina , Fumar , Telomerasa , Telómero , Proteína 2 de Unión a Repeticiones Teloméricas , Humanos , Inflamación/genética , Inflamación/patología , Envejecimiento/genética , Proteína 2 de Unión a Repeticiones Teloméricas/metabolismo , Proteína 2 de Unión a Repeticiones Teloméricas/genética , Citocinas/metabolismo , Telómero/metabolismo , Telomerasa/metabolismo , Telomerasa/genética , Fumar/efectos adversos , Ubiquitinas/metabolismo , Ubiquitinas/genética , Proteínas de Unión a Telómeros/metabolismo , Proteínas de Unión a Telómeros/genética , Interferón gamma/metabolismo , Homeostasis del Telómero , Masculino , Acortamiento del Telómero , Femenino , Persona de Mediana EdadRESUMEN
Biologists aim to explain patterns of growth, reproduction and ageing that characterize life histories, yet we are just beginning to understand the proximate mechanisms that generate this diversity. Existing research in this area has focused on telomeres but has generally overlooked the telomere's most direct mediator, the shelterin protein complex. Shelterin proteins physically interact with the telomere to shape its shortening and repair. They also regulate metabolism and immune function, suggesting a potential role in life history variation in the wild. However, research on shelterin proteins is uncommon outside of biomolecular work. Intraspecific analyses can play an important role in resolving these unknowns because they reveal subtle variation in life history within and among populations. Here, we assessed ecogeographic variation in shelterin protein abundance across eight populations of tree swallow (Tachycineta bicolor) with previously documented variation in environmental and life history traits. Using the blood gene expression of four shelterin proteins in 12-day-old nestlings, we tested the hypothesis that shelterin protein gene expression varies latitudinally and in relation to both telomere length and life history. Shelterin protein gene expression differed among populations and tracked non-linear variation in latitude: nestlings from mid-latitudes expressed nearly double the shelterin mRNA on average than those at more northern and southern sites. However, telomere length was not significantly related to latitude. We next assessed whether telomere length and shelterin protein gene expression correlate with 12-day-old body mass and wing length, two proxies of nestling growth linked to future fecundity and survival. We found that body mass and wing length correlated more strongly (and significantly) with shelterin protein gene expression than with telomere length. These results highlight telomere regulatory shelterin proteins as potential mediators of life history variation among populations. Together with existing research linking shelterin proteins and life history variation within populations, these ecogeographic patterns underscore the need for continued integration of ecology, evolution and telomere biology, which together will advance understanding of the drivers of life history variation in nature.
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POT1 (Protection of Telomeres 1) is a key component of the six-membered shelterin complex that plays a critical role in telomere protection and length regulation. Germline variants in the POT1 gene have been implicated in predisposition to cancer, primarily to melanoma and chronic lymphocytic leukemia (CLL). We report the identification of POT1 p.(I78T), previously ranked with conflicting interpretations of pathogenicity, as a founder pathogenic variant among Ashkenazi Jews (AJs) and describe its unique clinical landscape. A directed database search was conducted for individuals referred for genetic counselling from 2018 to 2023. Demographic, clinical, genetic, and pathological data were collected and analyzed. Eleven carriers, 25 to 67 years old, from ten apparently unrelated families were identified. Carriers had a total of 30 primary malignancies (range 1-6); nine carriers (82%) had recurrent melanoma between the ages of 25 and 63 years, three carriers (27%) had desmoid tumors, three (27%) had papillary thyroid cancer (PTC), and five women (63% of female carriers) had breast cancer between the ages of 44 and 67 years. Additional tumors included CLL; sarcomas; endocrine tumors; prostate, urinary, and colorectal cancers; and colonic polyps. A review of a local exome database yielded an allelic frequency of the variant of 0.06% among all ethnicities and of 0.25% in AJs. A shared haplotype was found in all carriers tested. POT1 p.(I78T) is a founder disease-causing variant associated with early-onset melanoma and additional various solid malignancies with a high tumor burden. We advocate testing for this variant in high-risk patients of AJ descent. The inclusion of POT1 in germline panels for various types of cancer is warranted.
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Leucemia Linfocítica Crónica de Células B , Melanoma , Neoplasias Cutáneas , Neoplasias de la Tiroides , Masculino , Humanos , Femenino , Adulto , Persona de Mediana Edad , Anciano , Melanoma/genética , Leucemia Linfocítica Crónica de Células B/genética , Proteínas de Unión a Telómeros/genética , Neoplasias Cutáneas/genética , Complejo ShelterinaRESUMEN
The Protection of Telomere 1 (POT1) gene was identified as a melanoma predisposition candidate nearly 10 years ago. Thereafter, various cancers have been proposed as associated with germline POT1 variants in the context of the so-called POT1 Predisposition Tumor Syndrome (POT1-TPD). While the key role, and related risks, of the alterations in POT1 in melanoma are established, the correlation between germline POT1 variants and the susceptibility to other cancers partially lacks evidence, due also to the rarity of POT1-TPD. Issues range from the absence of functional or segregation studies to biased datasets or the need for a revised classification of variants. Furthermore, a proposal of a surveillance protocol related to the cancers associated with POT1 pathogenic variants requires reliable data to avoid an excessive, possibly unjustified, burden for POT1 variant carriers. We propose a critical perspective regarding data published over the last 10 years that correlate POT1 variants to various types of cancer, other than cutaneous melanoma, to offer food for thought for the specialists who manage cancer predisposition syndromes and to stimulate a debate on the grey areas that have been exposed.
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Melanoma , Neoplasias Cutáneas , Humanos , Melanoma/genética , Neoplasias Cutáneas/genética , Alimentos , Síndrome , Telómero/genética , Complejo Shelterina , Proteínas de Unión a Telómeros/genéticaRESUMEN
A whole exome sequencing (WES)-driven approach to uncover the etiology of unexplained inflammatory gastritides has been underutilized by surgical pathologists. Here, we discovered the pathobiology of an unusual chronic atrophic gastritis in two unrelated patients using this approach. The gastric biopsies were notable for an unusual pattern of gastritis with persistent dense inflammation, loss of both parietal and neuroendocrine cells in the oxyntic mucosa, and sparing of the antral mucosa. The patients were found to harbor pathogenic variants in telomeropathic genes (POT1 and DCLRE1B). Clonality testing for one of the patients showed evidence of evolving clonality of TCR-gene rearrangement. Both patients showed significantly decreased numbers of stem/progenitor cells by immunohistochemistry, which appears to be responsible for the development of mucosal atrophy. No such cases of unusual chronic atrophic gastritis in the setting of telomeropathy have been previously reported. The loss of stem/progenitor cells suggests that stem/progenitor cell exhaustion in the setting of telomere dysfunction is the likely mechanism for development of this unusual chronic atrophic gastritis. The results underscore the need for close monitoring of these gastric lesions, with special regard to their neoplastic potential. This combined WES-driven approach has promise to identify the cause and mechanism of other uncharacterized gastrointestinal inflammatory disorders.
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Gastritis Atrófica , Gastritis , Humanos , Gastritis Atrófica/genética , Gastritis Atrófica/patología , Secuenciación del Exoma , Gastritis/genética , Gastritis/patología , Biopsia , Biología , ExodesoxirribonucleasasRESUMEN
Though telomeres play a crucial role in maintaining genomic stability in cancer cells and have emerged as attractive therapeutic targets in anticancer therapy, the relationship between telomere dysfunction and genomic instability induced by irradiation is still unclear. In this study, we identified that protection of telomeres 1 (POT1), a single-stranded DNA (ssDNA)-binding protein, was upregulated in γ-irradiated HeLa cells and in cancer patients who exhibit radiation tolerance. Knockdown of POT1 delayed the repair of radiation-induced telomeric DNA damage which was associated with enhanced H3K9 trimethylation and enhanced the radiosensitivity of HeLa cells. The depletion of POT1 also resulted in significant genomic instability, by showing a significant increase in end-to-end chromosomal fusions, and the formation of anaphase bridges and micronuclei. Furthermore, knockdown of POT1 disturbed telomerase recruitment to telomere, and POT1 could interact with phosphorylated ATM (p-ATM) and POT1 depletion decreased the levels of p-ATM induced by irradiation, suggesting that POT1 could regulate the telomerase recruitment to telomeres to repair irradiation-induced telomeric DNA damage of HeLa cells through interactions with p-ATM. The enhancement of radiosensitivity in cancer cells can be achieved through the combination of POT1 and telomerase inhibitors, presenting a potential approach for radiotherapy in cancer treatment.
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Telomerasa , Neoplasias del Cuello Uterino , Humanos , Femenino , Complejo Shelterina , Proteínas de Unión a Telómeros/genética , Proteínas de Unión a Telómeros/metabolismo , Neoplasias del Cuello Uterino/genética , Neoplasias del Cuello Uterino/radioterapia , Células HeLa , Telomerasa/genética , Telómero/genética , Inestabilidad Genómica , Daño del ADNRESUMEN
PURPOSE: Germline variants in POT1 have been implicated in predisposition to melanoma, sarcoma, and glioma in limited studies. Here, we determine the prevalence of cancer types in individuals with POT1 pathogenic variants (PVs) undergoing multigene panel testing (MGPT) for a broad variety of cancer indications. METHODS: We performed a retrospective review of data provided on clinical documents from individuals with POT1 PVs identified via MGPT over a 5-year period. Tumor prevalence in POT1 PV heterozygotes was compared with MGPT-negative wild-type (WT) controls using χ2 test. RESULTS: POT1 PVs were identified in 227 individuals. POT1 PV and WT (n = 13,315) cohorts had a similar proportion of reported tumors (69.6% and 69.2%, respectively); however, POT1 PV heterozygotes were more likely to be diagnosed with multiple tumors (18.9% vs 8.7%; P < .001). Compared with POT1 WT, we identified a significant increase in melanoma (odds ratio 7.03; 95% CI 4.7-10.5; P < .001) and sarcoma (odds ratio 6.6; 95% CI 3.1-13.9; P < .001). CONCLUSION: This analysis of the largest POT1 PV cohort to date validates the inclusion of POT1 in hereditary cancer MGPT and has the potential to impact clinical management recommendations, particularly for patients and families at risk for melanoma and sarcoma.
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Melanoma , Sarcoma , Humanos , Predisposición Genética a la Enfermedad , Prevalencia , Melanoma/epidemiología , Melanoma/genética , Mutación de Línea Germinal/genética , Pruebas Genéticas , Complejo Shelterina , Proteínas de Unión a Telómeros/genéticaRESUMEN
Telomere maintenance requires extension of the G-rich telomeric repeat strand by telomerase and fill-in synthesis of the C-rich strand by Polα/Primase. Telomeric Polα/Primase is bound to Ctc1-Stn1-Ten1 (CST), a single-stranded DNA-binding complex. Like mutations in telomerase, mutations affecting CST-Polα/Primase result in pathological telomere shortening and cause a telomere biology disorder, Coats plus (CP). We determined cryogenic electron microscopy structures of human CST bound to the shelterin heterodimer POT1/TPP1 that reveal how CST is recruited to telomeres by POT1. Phosphorylation of POT1 is required for CST recruitment, and the complex is formed through conserved interactions involving several residues mutated in CP. Our structural and biochemical data suggest that phosphorylated POT1 holds CST-Polα/Primase in an inactive auto-inhibited state until telomerase has extended the telomere ends. We propose that dephosphorylation of POT1 releases CST-Polα/Primase into an active state that completes telomere replication through fill-in synthesis.
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The protection of telomere protein (POT1) is a telomere-binding protein and is an essential component of the six-membered shelterin complex, which is associated with the telomeres. POT1 directly binds to the 3' single-stranded telomeric overhang and prevents the activation of DNA damage response at telomeres thus preventing the telomere-telomere fusions and genomic instability. POT1 also plays a pivotal role in maintaining telomere length by regulating telomerase-mediated telomere elongation. Mutations in POT1 proteins result in three different telomere phenotypes, which include long, short, or aberrant telomere length. Long telomeres predispose individuals to cancer, while short or aberrant telomere phenotypes result in pro-aging diseases referred to as telomeropathies. Here, we review the function of POT1 proteins in telomere length hemostasis and how the spectrum of mutations reported in POT1 can be segregated toward developing very distinct disease phenotypes of cancer and telomeropathies.
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Complejo Shelterina , Proteínas de Unión a Telómeros , Telómero , Mutación/genética , Fenotipo , Telómero/genética , Telómero/metabolismo , Proteínas de Unión a Telómeros/genética , Proteínas de Unión a Telómeros/metabolismo , HumanosRESUMEN
Background: Spitzoid morphology in familial melanoma has been associated with germline variants in POT1, a telomere maintenance gene (TMG), suggesting a link between telomere biology and spitzoid differentiation. Objective: To assess if familial melanoma cases associated with germline variants in TMG (POT1, ACD, TERF2IP, and TERT) commonly exhibit spitzoid morphology. Methods: In this case series, melanomas were classified as having spitzoid morphology if at least 3 of 4 dermatopathologists reported this finding in ≥25% of tumor cells. Logistic regression was used to calculate odds ratios (OR) of spitzoid morphology compared to familial melanomas from unmatched noncarriers that were previously reviewed by a National Cancer Institute dermatopathologist. Results: Spitzoid morphology was observed in 77% (23 of 30), 75% (3 of 4), 50% (2 of 4), and 50% (1 of 2) of melanomas from individuals with germline variants in POT1, TERF2IP, ACD, and TERT, respectively. Compared to noncarriers (n = 139 melanomas), POT1 carriers (OR = 225.1, 95% confidence interval: 51.7-980.5; P < .001) and individuals with TERF2IP, ACD, and TERT variants (OR = 82.4, 95% confidence interval: 21.3-494.6; P < .001) had increased odds of spitzoid morphology. Limitations: Findings may not be generalizable to nonfamilial melanoma cases. Conclusion: Spitzoid morphology in familial melanoma could suggest germline alteration of TMG.
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We explored the association between variations in the telomere maintenance genes and change in telomere length (TL) in workers. The TL of peripheral blood leukocytes from 544 coke oven workers and 238 controls were detected using the Real-time PCR method. Variations in four genes were then detected using the PCR based restriction fragment length polymorphism. The effects of environmental and genetic factors on TL were subsequently analyzed through covariance analysis and a generalized linear model .The TL of subjects with GG genotypes were longer than those with AG genotype in the TERT rs2736098 locus amongst the controls (P = .032). The combined effect of COEs exposure and AG+AA genotypes had a significant effect on TL (P < .001). The interaction between the COEs exposure factor and the rs2736098AG+AA genotypes had a significant effect on the TL (P < .05). The TL in coke oven workers is associated with the interactions between TERT rs2736098 AG+AA and COEs exposure.
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Coque , Exposición Profesional , Hidrocarburos Policíclicos Aromáticos , Telomerasa , Humanos , Coque/efectos adversos , Genotipo , Exposición Profesional/efectos adversos , Exposición Profesional/análisis , Hidrocarburos Policíclicos Aromáticos/análisis , Polimorfismo Genético , Telomerasa/genética , Telómero/químicaRESUMEN
Objective:To investigate the correlation between telomere dysfunction of human gastric mucosa and chronic atrophic gastritis (CAG).Methods:From February 12, 2019 to July 10, 2020, at Endoscopy Center, Guang′anmen Hospital, China Academy of Chinese Sciences, 30 patients received endoscopy and pathological diagnosed with CAG (CAG group) were collected, and 30 patients with chronic non-atrophic gastritis (CNAG) were collected at the same time (CNAG group). The relative telomere length was detected by real time fluorescent quantitative polymerase chain reaction. The expression of telomere repeat binding factor (TRF) 1, TRF2 and protection of telomere (POT) 1 at protein level were detected by immunohistochemical staining and semi-quantitative analysis. Spearman analysis was used to analyze the correlation between the relative telomere length of gastric mucosa and the protein expression levels of TRF1, TRF2 and POT1. Mann-Whitney U test and independent sample t test were used for statistical analysis. Results:The relative telomere length of the gastric mucosa in the CAG group was shorter than that in the CNAG group (0.67 (0.51 to 1.17) vs. 1.06(0.69 to 1.37)), and the difference was statistically significant ( U=297.00, P=0.024). The protein expression levels of TRF1, TRF2, and POT1 in the CAG group were all higher than those in the CNAG group, respectively (4.26±2.49 vs. 1.86±1.34, 10.12±2.76 vs. 8.78±2.81, 4.22±2.48 vs. 2.53±1.62), and the differences were statistically significant ( t=8.05, 3.23, 5.39; P<0.001, =0.001, and <0.001). In the CAG group, the protein expression levels of TRF2 and POT1 in gastric mucosa were negatively correlated with the relative telomere length ( r=-0.477 and -0.417, P=0.008 and 0.022). Conclusions:The telomere dysfunction is related to the pathogenesis of CAG. The change of telomere binding protein expression level is involved in the shortening of telomere and pathological process of CAG patients.
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Background: Li-Fraumeni syndrome (LFS) and Li-Fraumeni-like (LFL) syndrome are rare hereditary diseases characterized by predisposition to a diverse spectrum of cancer types, primarily sarcoma. The pathogenic variants underlying the majority of LFL cases remain to be explored. Methods: We performed whole-exome sequencing (WES) on 13 core members of a large LFL family with highly aggregated incidences of cancers, including cases with sarcoma, non-small cell lung cancer and cardiac angiosarcoma, and conducted a comprehensive literature review of candidate gene associations in LFS/LFL syndromes or sarcoma to identify potential pathogenic germline variants. Results: No germline variants in the best-known LFL/LFS-associated gene TP53 were detected. Of all the genes associated with LFS/LFL or sarcoma that we have surveyed, we identified a novel p.P35L germline variant in POT1 (protection of telomeres 1). Germline and somatic alterations in POT1 have been implicated in a series of familial cancers, including angiosarcoma, glioma, melanoma and colorectal cancer. This particular variant is located in the telomere-binding OB1 domain, which is important in maintaining the proper telomere length, and showed high conservation across different POT1 orthologues. No record of the variant was found in any of the 1000 genomes, ExAC, gnomAD, dpSNP and COSMIC databases. Prediction algorithms and in silico structural analysis suggested completely disrupted protein structure and function of POT1 in the presence of this mutation. Conclusions: Leveraging WES, we identified a novel germline risk allele, p.P35L in POT1, that likely predisposes to LFL syndrome. Our results support the routine testing of POT1 and other LFL/LFS-associated genes in the risk populations to enable early cancer diagnosis, prevention and intervention.
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Zbtb34 is a novel zinc finger protein, which is revealed by biological software analysis to have 3 zinc fingers, but its functions remain unknown. In this study, mouse Zbtb34 cDNA was amplified by PCR and inserted into the plasmid pEGFP-N1 to generate Zbtb34-EGFP fusion protein. The upregulation of Zbtb34 in mouse embryonic stem cells promoted telomere elongation and increased cell proliferation. In order to understand the above phenomena, the telomere co-immunoprecipitation technique was employed to investigate the relationship between Zbtb34 and telomeres. The results indicated that Zbtb34 could bind to the DNA sequences of the telomeres. Alanine substitution of the third zinc finger abolished such binding. Since Pot1 is the only protein binding to the single-stranded DNA at the end of the telomeres, we further investigated the relationship between Zbtb34 and Pot1. The results revealed that the upregulation of Zbtb34 decreased the binding of Pot1b to the telomeres. Through the upregulation of Pot1b, the binding of Zbtb34 to the telomeres was also reduced. In conclusion, we showed that the main biological function of Zbtb34 was to bind telomere DNA via its third ZnF, competing with Pot1b for the binding sites, resulting in telomere elongation and cell proliferation.
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ADN de Cadena Simple , Proteínas Represoras , Proteínas de Unión a Telómeros , Animales , Ratones , Alanina/genética , Proliferación Celular , ADN , ADN Complementario , Proteínas de Unión al ADN/genética , Células Madre Embrionarias/metabolismo , Proteínas Represoras/metabolismo , Complejo Shelterina , Telómero/genética , Telómero/metabolismo , Proteínas de Unión a Telómeros/genética , Proteínas de Unión a Telómeros/metabolismoRESUMEN
Diffuse large B-cell lymphoma (DLBCL) represents one of the most frequent and deadliest neoplasia in dogs worldwide and is characterized by a remarkable degree of clinical heterogeneity, with poor chances to anticipate the outcome. Even if in the last years some recurrently mutated genes have been identified, the genetic origin of canine DLBCL (cDLBCL) is not yet completely understood. The aim of the present study was to assess the prevalence of POT1 mutations in cDLBCL and to elucidate the role of such gene in the pathogenesis of this tumor. Mutations in POT1 were retrieved in 34% of cases, in line with previous reports, but no significant associations with any clinico-pathological variable were identified. Likewise, POT1 mutations are not predictive of worse prognosis. Interestingly, Ki-67 index was significantly higher in dogs harboring POT1 mutations compared to wild-type ones. These results suggest that POT1 mutations may exert their pathogenic role in cDLBCL by promoting cellular proliferation.
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Systematic literature searches on POT1/POLE/BAP1 found that limited skin phenotypic characteristics have been documented in mutation carriers; 248 variants were annotated, and high-cluster variant regions associated with cutaneous melanoma were found in all three genes. Genotype-phenotype correlations can be used to identify patient disease predisposition based on mutation position and cluster regions.