Loading...
14 results
Search Results
Now showing 1 - 10 of 14
- THOR is a targetable epigenetic biomarker with clinical implications in breast cancerPublication . Apolónio, Joana; Dias, João S.; Fernandes, Mónica T.; Komosa, Martin; Lipman, Tatiana; Zhang, Cindy H.; Leão, Ricardo; Lee, Donghyun; Nunes, Nuno M.; Maia, Ana-Teresa; Morera, José L.; Vicioso, Luis; Tabori, Uri; Castelo-Branco, PedroBreast cancer (BC) is the most frequently diagnosed cancer and a leading cause of death among women worldwide. Early BC is potentially curable, but the mortality rates still observed among BC patients demon‑ strate the urgent need of novel and more efective diagnostic and therapeutic options. Limitless self-renewal is a hallmark of cancer, governed by telomere maintenance. In around 95% of BC cases, this process is achieved by telom‑ erase reactivation through upregulation of the human telomerase reverse transcriptase (hTERT). The hypermethylation of a specifc region within the hTERT promoter, termed TERT hypermethylated oncological region (THOR) has been associated with increased hTERT expression in cancer. However, its biological role and clinical potential in BC have never been studied to the best of our knowledge. Therefore, we aimed to investigate the role of THOR as a biomarker and explore the functional impact of THOR methylation status in hTERT upregulation in BC.
- The TERT hypermethylated oncologic region predicts recurrence and survival in pancreatic cancerPublication . Faleiro, Inês; Apolónio, Joana; Price, Aryeh J.; De Mello, Ramon Andrade; Roberto, Vânia; Tabori, Uri; Castelo-Branco, PedroAim: We explore the biomarker potential of the TERT hypermethylated oncologic region (THOR) in pancreatic cancer. Materials & methods: We assessed the methylation status of THOR using the cancer genome atlas data on the cohort of pancreatic cancer (n = 193 patients). Results: THOR was significantly hypermethylated in pancreatic tumor tissue when compared with the normal tissue used as control (p < 0.0001). Also, THOR hypermethylation could distinguish early stage I disease from normal tissue and was associated with worse prognosis. Discussion: We found that THOR is hypermethylated in pancreatic tumor tissue when compared with normal tissue and that THOR methylation correlates with TERT expression in tumor samples. Conclusion: Our preliminary findings support the diagnostic and prognostic values of THOR in pancreatic cancer.
- Measuring healthy ageing: current and future toolsPublication . Silva, Nádia; Rajado, Ana Teresa; Esteves, Filipa; Brito, David V.C.; Apolónio, Joana; Roberto, Vânia; Binnie, Alexandra; Araújo, Inês Maria; Nóbrega, Clévio; Bragança, José; Castelo-Branco, PedroHuman ageing is a complex, multifactorial process characterised by physiological damage, increased risk of age-related diseases and inevitable functional deterioration. As the population of the world grows older, placing significant strain on social and healthcare resources, there is a growing need to identify reliable and easy-to-employ markers of healthy ageing for early detection of ageing trajectories and disease risk. Such markers would allow for the targeted implementation of strategies or treatments that can lessen suffering, disability, and dependence in old age. In this review, we summarise the healthy ageing scores reported in the literature, with a focus on the past 5 years, and compare and contrast the variables employed. The use of approaches to determine biological age, molecular biomarkers, ageing trajectories, and multi-omics ageing scores are reviewed. We conclude that the ideal healthy ageing score is multisystemic and able to encompass all of the potential alterations associated with ageing. It should also be longitudinal and able to accurately predict ageing complications at an early stage in order to maximize the chances of successful early intervention.
- No induction of antimicrobial resistance in Staphylococcus aureus and Listeria monocytogenes during continuous exposure to eugenol and citralPublication . Apolonio, Joana; Faleiro, Maria L.; Miguel, Maria Graca; Neto, LuisThe aim of this study was to evaluate the adaptation response of Staphylococcus aureus, methicillin-resistant S.aureus (MRSA), and Listeria monocytogenes to the essential oil (EO), eugenol, and citral. The minimum inhibitory concentration of eugenol and citral was determined by agar dilution and microdilution. Adaptation to eugenol and citral was done by sequential exposure of the pathogens to increasing concentrations of the essential oils. The M2-A9 standard was used to determine the antibiotic susceptibility. The effect of eugenol and citral on the adherence ability was evaluated by the crystal violet assay. The impact of adaptation to eugenol on virulence was estimated using the Galleria mellonella model. No development of resistance to the components and antibiotics was observed in the adapted cells of S.aureus, MRSA, and L.monocytogenes. Eugenol and citral at subinhibitory concentration reduced the bacterial adherence. Adaptation to subinhibitory concentration of eugenol affected the virulence potential of S.aureus, MRSA, and L.monocytogenes. Eugenol and citral do not pose a risk of resistance development in a continuous mode of use. These EO components showed a high efficacy as antistaphylococcal and antilisterial biofilm agents. Adaptation at subinhibitory concentration of eugenol protected the larvae against listerial and staphylococcal infection.
- Mechanisms of human telomerase reverse transcriptase (hTERT) regulation: clinical impacts in cancerPublication . Leão, Ricardo; Apolónio, Joana; Lee, Donghyun; Figueiredo, Arnaldo; Tabori, Uri; Castelo-Branco, PedroBackground Limitless self-renewal is one of the hallmarks of cancer and is attained by telomere maintenance, essentially through telomerase (hTERT) activation. Transcriptional regulation of hTERT is believed to play a major role in telomerase activation in human cancers. Main body The dominant interest in telomerase results from its role in cancer. The role of telomeres and telomere maintenance mechanisms is well established as a major driving force in generating chromosomal and genomic instability. Cancer cells have acquired the ability to overcome their fate of senescence via telomere length maintenance mechanisms, mainly by telomerase activation. hTERT expression is up-regulated in tumors via multiple genetic and epigenetic mechanisms including hTERT amplifications, hTERT structural variants, hTERT promoter mutations and epigenetic modifications through hTERT promoter methylation. Genetic (hTERT promoter mutations) and epigenetic (hTERT promoter methylation and miRNAs) events were shown to have clinical implications in cancers that depend on hTERT activation. Knowing that telomeres are crucial for cellular self-renewal, the mechanisms responsible for telomere maintenance have a crucial role in cancer diseases and might be important oncological biomarkers. Thus, rather than quantifying TERT expression and its correlation with telomerase activation, the discovery and the assessment of the mechanisms responsible for TERT upregulation offers important information that may be used for diagnosis, prognosis, and treatment monitoring in oncology. Furthermore, a better understanding of these mechanisms may promote their translation into effective targeted cancer therapies. Conclusion Herein, we reviewed the underlying mechanisms of hTERT regulation, their role in oncogenesis, and the potential clinical applications in telomerase-dependent cancers.
- Tert hypermethylated oncologic region (THOR) as a biomarker for breast cancerPublication . Apolónio, Joana; Castelo-Branco, Pedro; Tabori, UriBreast cancer (BC) is the most frequently diagnosed cancer and a leading cause of death among women worldwide. Early BC is potentially curable, nevertheless, the mortality rates still observed among BC patients, demonstrates the urgent need of novel and more effective diagnostic and therapeutic options. Limitless self-renewal is a hallmark of cancer governed by telomere maintenance. In around 95% of BC cases, this process is achieved by telomerase reactivation through upregulation of human Telomerase Reverse Transcriptase (hTERT). The hypermethylation of a specific region within hTERT promoter, termed TERT Hypermethylated Oncological Region (THOR) has been associated with increased hTERT expression in cancer. However, its biological role and clinical potential in BC has never been studied. Therefore, we aimed to investigate the role of THOR as a biomarker, explore the functional impact of THOR in hTERT upregulation, and also identify other potential DNA methylation-based markers in BC. Firstly, we demonstrated that THOR is significantly hypermethylated in malignant breast tissue when compared to benign tissue (40.23% vs. 12.81%), representing a potential candidate biomarker for future application in BC screening and early diagnosis. Importantly, as DNA methylation marks can be determined from blood samples, assessing THOR methylation status may constitute a non-invasive assay to help in BC management. Next, using a reporter assay, we revealed that THOR acts as a repressive regulatory element of hTERT, and that THOR hypermethylation might be relevant for hTERT upregulation in BC. To further investigate its biological impact on hTERT transcription, targeted THOR demethylation was performed using the CRISPR-dCas9 system. Although, THOR demethylation was achieved, hTERT mRNA levels were not significantly reduced. Surprisingly, cells previously demethylated on THOR region led to a remarkable reduction in tumor development in vivo. Therefore, additional studies are required to validate these observations and to unravel the causality between THOR hypermethylation and hTERT upregulation in BC. Finally, through a genome-wide methylation analysis, we identified three novel DNA methylation markers, located on the PRAC2, TDRD10 and TMEM132C genes that showed diagnostic and prognostic value in BC, as well as in other cancer types. This work evidences the importance of DNA methylation in breast tumorigenesis and, more importantly, their clinical value as promising diagnostic, prognostic and therapeutic targets in BC.
- Post-transcriptional silencing of Bos taurus prion family genes and its impact on granulosa cell steroidogenesisPublication . Pimenta, Jorge M.B.G.A.; Pires, Virgínia M.R.; Nolasco, Sofia; Castelo-Branco, Pedro; Marques, Carla C.; Apolónio, Joana; Azevedo, Rita; Fernandes, Mónica T.; Lopes-da-Costa, Luís; Prates, José; Pereira, Rosa M.L.N.Prion proteins constitute a major public health concern, which has partly overshadowed their physiological roles in several scenarios. Indeed, these proteins were implicated in male fertility but their role in female fertility is relatively less explored. This study was designed to evaluate the role of SPRN and PRNP prion family genes in bovine follicular steroidogenesis pathways. Post-transcriptional SPRN and PRNP silencing with siRNAs was established in bovine granulosa cell (GC) in vitro culture, and gene expression and progesterone and estradiol concentrations were evaluated. SPRN knockdown, led to a down regulation of CYP11A1 mRNA levels (2.1-fold), and PRNP knockdown led to an upregulation of SPRN mRNA levels (2.3-fold). CYP19A1 expression and estradiol synthesis was not detected in any experimental group. Finally, SPRN knockdown led to a mild reduction in progesterone production in GCs and this was the only experimental group that did not exhibit an increment in progesterone levels after 48 h of culture. As a conclusion, it was possible to detect the expression of the SPRN gene in bovine GCs, a potential interaction between SPRN and PRNP regulation, and the impact of SPRN expression on CYP11A1 and progesterone levels. These findings bring new insights into the role of these genes in ovarian steroidogenesis and female reproductive physiology. (c) 2022 Elsevier Inc. All rights reserved.
- Reprogramming iPSCs to study age-related diseases: models, therapeutics, and clinical trialsPublication . Esteves, Filipa; Brito, David; Rajado, Ana Teresa; Silva, Nádia; Apolónio, Joana; Roberto, Vania Palma; Araújo, Inês Maria; Nóbrega, Clévio; Castelo-Branco, Pedro; Bragança, José; P. Andrade, Raquel; M. Calado, Sofia; Faleiro, L; Matos, Carlos A; Marques, Nuno; Marreiros, Ana; Nzwalo, Hipólito; Pais, Sandra; Palmeirim, Isabel; S, Simão; Joaquim, Natércia; Miranda, Rui; Pêgas, António; Raposo, Daniela Marques; Sardo, AnaThe unprecedented rise in life expectancy observed in the last decades is leading to a global increase in the ageing population, and age-associated diseases became an increasing societal, economic, and medical burden. This has boosted major efforts in the scientific and medical research communities to develop and improve therapies to delay ageing and age-associated functional decline and diseases, and to expand health span. The establishment of induced pluripotent stem cells (iPSCs) by reprogramming human somatic cells has revolutionised the modelling and understanding of human diseases. iPSCs have a major advantage relative to other human pluripotent stem cells as their obtention does not require the destruction of embryos like embryonic stem cells do, and do not have a limited proliferation or differentiation potential as adult stem cells. Besides, iPSCs can be generated from somatic cells from healthy individuals or patients, which makes iPSC technology a promising approach to model and decipher the mechanisms underlying the ageing process and age-associated diseases, study drug effects, and develop new therapeutic approaches. This review discusses the advances made in the last decade using iPSC technology to study the most common age-associated diseases, including age-related macular degeneration (AMD), neurodegenerative and cardiovascular diseases, brain stroke, cancer, diabetes, and osteoarthritis.
- Epigenetic alterations in urothelial bladder cancer associated with disease outcomesPublication . Martins Nunes, Francisca; Apolónio, Joana; Mota-Pinto, A; Leão, RicardoObjectives: Bladder cancer (BLCA) is a molecular heterogeneous disease with known genetic distinctive signatures. However, DNA methylation is highly prevalent across a wide range of tumors, suggesting its potential in oncogenesis. Here, we aimed to interrogate the role of nine epigenetic alterations as diagnostic and prognostic markers in BLCA.Methods: DNA methylation, gene expression, and clinicopathological information were retrieved from The Cancer Genome Atlas data portal. Methylation values and gene expression were assessed to determine their association with normal and malignant tissue. Additionally, we studied the association between methylation values and clinicopathological variables. For the prognostic model, Kaplan-Meier Survival curves were generated. Lastly, univariate and multivariate analysis were performed to evaluate the simultaneous impact of methylation and clinicopathological variables on the risk of tumor progression and survival.Results: Nine CpG sites' methylation beta$$ \beta $$-values involved in our study demonstrated different methylation signatures between normal and malignant urothelium. Hypermethylated CpGs were overrepresented in tumor tissue (p < 0.0001). Opposingly, 4 CpG sites showed lower methylation values in tumor samples (p < 0.0001). Cg12743248high and cg17192862low are risk factors for progression-free survival, whereas cg12374721high (HR:3.003 (1.283-7.030)) also demonstrated to be the most valuable independent risk factor for disease progression and a risk factor for overall survival.Conclusions: We have identified that methylated cg12374721 shows promise as a diagnostic and independent prognostic marker in BLCA progression.
- Roadmap of DNA methylation in breast cancer identifies novel prognostic biomarkersPublication . Almeida, Bernardo; Apolónio, Joana; Binnie, Alexandra; Castelo-Branco, PedroBackground Breast cancer is a highly heterogeneous disease resulting in diverse clinical behaviours and therapeutic responses. DNA methylation is a major epigenetic alteration that is commonly perturbed in cancers. The aim of this study is to characterize the relationship between DNA methylation and aberrant gene expression in breast cancer. Methods We analysed DNA methylation and gene expression profiles from breast cancer tissue and matched normal tissue in The Cancer Genome Atlas (TCGA). Genome-wide differential methylation analysis and methylation-gene expression correlation was performed. Gene expression changes were subsequently validated in the METABRIC dataset. The Oncoscore tool was used to identify genes that had previously been associated with cancer in the literature. A subset of genes that had not previously been studied in cancer was chosen for further analysis. Results We identified 368 CpGs that were differentially methylated between tumor and normal breast tissue (∆β > 0.4). Hypermethylated CpGs were overrepresented in tumor tissue and were found predominantly (56%) in upstream promoter regions. Conversely, hypomethylated CpG sites were found primarily in the gene body (66%). Expression analysis revealed that 209 of the differentially-methylated CpGs were located in 169 genes that were differently expressed between normal and breast tumor tissue. Methylation-expression correlations were predominantly negative (70%) for promoter CpG sites and positive (74%) for gene body CpG sites. Among these differentially-methylated and differentially-expressed genes, we identified 7 that had not previously been studied in any form of cancer. Three of these, TDRD10, PRAC2 and TMEM132C, contained CpG sites that showed diagnostic and prognostic value in breast cancer, particularly in estrogen-receptor (ER)-positive samples. A pan-cancer analysis confirmed differential expression of these genes together with diagnostic and prognostic value of their respective CpG sites in multiple cancer types. Conclusion We have identified 368 DNA methylation changes that characterize breast cancer tumor tissue, of which 209 are associated with genes that are differentially-expressed in the same samples. Novel DNA methylation markers were identified, of which cg12374721 (PRAC2), cg18081940 (TDRD10) and cg04475027 (TMEM132C) show promise as diagnostic and prognostic markers in breast cancer as well as other cancer types.