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127
result(s) for
"Castelo-Branco, Pedro"
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Roadmap of DNA methylation in breast cancer identifies novel prognostic biomarkers
by
de Almeida, Bernardo P.
,
Castelo-Branco, Pedro
,
Apolónio, Joana Dias
in
Analysis
,
Biochemistry
,
Biological markers
2019
Background
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.
Journal Article
Mechanisms of human telomerase reverse transcriptase (hTERT) regulation: clinical impacts in cancer
by
Castelo-Branco, Pedro
,
Apolónio, Joana Dias
,
Figueiredo, Arnaldo
in
Biomedical and Life Sciences
,
Biomedicine
,
Cancer biomarkers
2018
Background
Limitless self-renewal is one of the hallmarks of cancer and is attained by telomere maintenance, essentially through telomerase (h
TERT
) activation. Transcriptional regulation of h
TERT
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.
h
TERT
expression is up-regulated in tumors via multiple genetic and epigenetic mechanisms including h
TERT
amplifications, h
TERT
structural variants, h
TERT
promoter mutations and epigenetic modifications through h
TERT
promoter methylation. Genetic (h
TERT
promoter mutations) and epigenetic (h
TERT
promoter methylation and miRNAs) events were shown to have clinical implications in cancers that depend on h
TERT
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 h
TERT
regulation, their role in oncogenesis, and the potential clinical applications in telomerase-dependent cancers.
Journal Article
Trichostatin A and Oncolytic HSV Combination Therapy Shows Enhanced Antitumoral and Antiangiogenic Effects
by
Castelo-Branco, Pedro
,
Liu, Ta-Chiang
,
Martuza, Robert L
in
Adenoviruses
,
Angiogenesis Inhibitors - pharmacology
,
Animals
2008
Oncolytic herpes simplex viruses (HSVs) possess direct oncolytic and antiangiogenic activities and are promising anticancer agents, but their efficacy, when used as single agents, leaves room for improvement. We investigated whether combination therapy of HSV with histone deacetylase inhibitor trichostatin A (TSA), an agent that also targets cancer cells and tumor vasculature, would result in enhanced efficacy. In vitro, TSA and G47Δ showed strong synergy of action against proliferating endothelial cells, varying degrees of synergistic action against most cancer cell lines, but no effect in quiescent, normal endothelial and prostate epithelial cells. Synergy is dependent on viral replication; however, it is not dependent on the dosing sequence of TSA and G47Δ, viral genetic alterations, infectivity, or replication kinetics of G47Δ. Using an isogenic cell system, we found that a high level of cellular cyclin D1 is also critically important for the interaction. Normal cells with low cyclin D1 levels were not subjected to toxicity by either agent. In tumor cells and proliferating endothelial cells, the combination treatment enhanced the inhibition of cyclin D1 and vascular endothelial growth factor (VEGF). Concurrent systemic TSA and intratumoral G47Δ administration resulted in enhanced antiangiogenesis and enhanced antitumoral efficacy in animal models. Therefore, combination treatment with TSA and oncolytic HSV provides a novel approach to cancer therapy.
Journal Article
Genomic analysis of diffuse intrinsic pontine gliomas identifies three molecular subgroups and recurrent activating ACVR1 mutations
2014
Cynthia Hawkins, Oren Becher and colleagues report the identification of recurrent mutations in
ACVR1
in 20% of diffuse intrinsic pontine gliomas.
Diffuse intrinsic pontine glioma (DIPG) is a fatal brain cancer that arises in the brainstem of children, with no effective treatment and near 100% fatality. The failure of most therapies can be attributed to the delicate location of these tumors and to the selection of therapies on the basis of assumptions that DIPGs are molecularly similar to adult disease. Recent studies have unraveled the unique genetic makeup of this brain cancer, with nearly 80% found to harbor a p.Lys27Met histone H3.3 or p.Lys27Met histone H3.1 alteration. However, DIPGs are still thought of as one disease, with limited understanding of the genetic drivers of these tumors. To understand what drives DIPGs, we integrated whole-genome sequencing with methylation, expression and copy number profiling, discovering that DIPGs comprise three molecularly distinct subgroups (H3-K27M, silent and MYCN) and uncovering a new recurrent activating mutation affecting the activin receptor gene
ACVR1
in 20% of DIPGs. Mutations in
ACVR1
were constitutively activating, leading to SMAD phosphorylation and increased expression of the downstream activin signaling targets
ID1
and
ID2
. Our results highlight distinct molecular subgroups and novel therapeutic targets for this incurable pediatric cancer.
Journal Article
DNA hypermethylation within TERT promoter upregulates TERT expression in cancer
2019
Replicative immortality is a hallmark of cancer cells governed by telomere maintenance. Approximately 90% of human cancers maintain their telomeres by activating telomerase, driven by the transcriptional upregulation of telomerase reverse transcriptase (TERT). Although TERT promoter mutations (TPMs) are a major cancer-associated genetic mechanism of TERT upregulation, many cancers exhibit TERT upregulation without TPMs. In this study, we describe the TERT hypermethylated oncological region (THOR), a 433-bp genomic region encompassing 52 CpG sites located immediately upstream of the TERT core promoter, as a cancer-associated epigenetic mechanism of TERT upregulation. Unmethylated THOR repressed TERT promoter activity regardless of TPM status, and hypermethylation of THOR counteracted this repressive function. THOR methylation analysis in 1,352 human tumors revealed frequent (>45%) cancer-associated DNA hypermethylation in 9 of 11 (82%) tumor types screened. Additionally, THOR hypermethylation, either independently or along with TPMs, accounted for how approximately 90% of human cancers can aberrantly activate telomerase. Thus, we propose that THOR hypermethylation is a prevalent telomerase-activating mechanism in cancer that can act independently of or in conjunction with TPMs, further supporting the utility of THOR hypermethylation as a prognostic biomarker.
Journal Article
Cellular Interactions in the Tumor Microenvironment: The Role of Secretome
2019
Over the past years, it has become evident that cancer initiation and progression depends on several components of the tumor microenvironment, including inflammatory and immune cells, fibroblasts, endothelial cells, adipocytes, and extracellular matrix. These components of the tumor microenvironment and the neoplastic cells interact with each other providing pro and antitumor signals. The tumor-stroma communication occurs directly between cells or via a variety of molecules secreted, such as growth factors, cytokines, chemokines and microRNAs. This secretome, which derives not only from tumor cells but also from cancer-associated stromal cells, is an important source of key regulators of the tumorigenic process. Their screening and characterization could provide useful biomarkers to improve cancer diagnosis, prognosis, and monitoring of treatment responses.
Journal Article
Halophyte plants as potential sources of Anticancer agents: a comprehensive review
by
Castelo-Branco, Pedro
,
Garcia-Caparros, Pedro
,
Pereira, Catarina Guerreiro
in
Antimitotic agents
,
Antineoplastic agents
,
Antioxidants
2022
Salt-tolerant plants (halophytes) are widely distributed worldwide in several environments such as coastal salt marshes, sand dunes, and inland deserts. To cope with the harsh conditions that characterize those habitats, which include high salinity and radiation levels, such plants have developed morphological and physiological traits, the latter including the synthesis and accumulation of important secondary metabolites such as alkaloids and polyphenols. While essential in maintaining plant homeostasis, these compounds are highly valued in the medical field for the treatment of several human diseases, including cancer. Cancer is one of the most life-threatening disorders worldwide, which accentuates the need to improve current cancer therapies and minimize potential adverse secondary side-effects. In this context, the pharmacological evaluation of natural compounds has attracted growing interest since nature has already provided some important anti-cancer drugs. This review compiles, for the first time, research regarding the anticancer activity of halophytes from different families, including, whenever possible, the bioactive molecules involved in such therapeutical properties along with possible mechanisms of action. The introduction section provides some pertinent information regarding cancer and a summary of the most important characteristics of halophytes. The next section gives information regarding the in vitro and in vivo cytotoxic properties of several halophyte species, grouped by families, including contents in bioactive metabolites and proposed modes of action, if possible. Lastly, the conclusion presents the most relevant metabolites and/or promising species and extracts that could be further explored in anticancer drug research.
Journal Article
La calidad de la democracia y la violencia en América Latina
by
Boas Branco, Castelo, Pedro H. Villas
,
Barbosa Gouvea, Carina
in
Armed forces
,
Autocracy
,
Corruption
2025
Las democracias representativas latinoamericanas han sufrido ataques que vienen minando sus estructuras y provocando déficits democráticos. La región latinoamericana también se ve rodeada de movimientos iliberales y antidemocráticos que abrazan la polarización y la reivindicación de la participación de los militares en la política. Se observa en América Latina una combinación de inclinaciones antidemocráticas y militaristas que resulta de convertir los adversarios políticos en enemigos, de una persecución de opositores mediante el uso de mecanismos de violencia, vigilancia y represión. Los escándalos de corrupción envolviendo las élites políticas y empresariales, la incapacidad de renovación de los partidos políticos, las demandas populares por una relación directa con sus liderazgos, la frustración derivada de crisis políticas y la carencia de servicios públicos básicos han provocado numerosas movilizaciones y protestas en diferentes países como Chile, Perú, México, Brasil, Colombia, entre otros países. Los enfoques metodológicos que buscan medir la calidad de las democracias carecen de criterios que tengan en cuenta el populismo, la militarización, la securitización y el militarismo. Investigar la calidad de la democracia en América Latina exige la comprensión de las formas de violencia que se manifiesta a través del militarismo y un proceso securitización y militarización, los que se reflejan, por ejemplo, en la apuesta de las Fuerzas Armadas como fuerza salvadora o guardia pretoriana de autócratas elegidos.
Journal Article
Prevalence and Diagnostic Comparison of Helicobacter pylori and Non-Helicobacter pylori Helicobacter Infections in Patients Undergoing Upper Gastrointestinal Endoscopy with Gastric Biopsy in Algarve, Portugal
by
Aguieiras, Catarina
,
Cortez Nunes, Francisco
,
Louro, Ricardo
in
Animals
,
Biopsy
,
Deoxyribonucleic acid
2025
H. pylori infects over half of the global population and is associated with various gastric and extra-gastric diseases. Other species, such as zoonotic non-Helicobacter pylori Helicobacters (NHPHs), have shown similar associations with gastritis and MALT lymphoma and H. pylori-negative cases with gastric disease have been identified, including gastric MALT lymphoma, chronic gastritis, and gastroduodenal ulcers. Accurate identification of these species is of great relevance but remains challenging using conventional diagnostic methods. This cross-sectional study aimed to determine the prevalence of H. pylori and NHPH infections, comparing standard histological protocols with molecular techniques. Between December 2024 and February 2025, 54 adult patients undergoing upper gastrointestinal endoscopy (UGE) with gastric biopsy in three hospitals in Algarve, Portugal were recruited. Endoscopic assessment was performed, and gastric biopsies were collected for histological and molecular analysis. DNA was extracted from antral biopsies and analyzed by conventional PCR to detect H. pylori and NHPH. H. pylori diagnostic techniques were compared, descriptive plus statistical analysis was performed, and p-values < 0.05 were considered to be statistically significant. Fifty-four patients were included in the study, with 51.9% of them presenting symptoms. Endoscopic gastritis was observed in 66.7% of patients, while histological gastritis was present in 88.9%, with statistically significant differences between the two diagnostic techniques (p = 0.004). Helicobacter spp. were identified in 44.4% (24/54) of the patients. H. pylori was detected in 42.6% of the patients by Modified Giemsa stain and in 33.3% by PCR. H. bizzozeronii was found in 35.9% of the patients, with 22.2% showing mixed infections. This study reveals a significant prevalence of Helicobacter spp. in patients from the Algarve region, with both H. pylori and zoonotic H. bizzozeronii detected. This is the first report of H. bizzozeronii DNA detection in gastric biopsies via PCR from patients undergoing UGE in Portugal, highlighting the need to consider NHPH in clinical diagnosis. It is important to include molecular methods in routine diagnostics and the need for broader studies to assess regional and national trends in Helicobacter infections besides H. pylori.
Journal Article
Molecular Detection of Multiple Antimicrobial Resistance Genes in Helicobacter pylori-Positive Gastric Samples from Patients Undergoing Upper Gastrointestinal Endoscopy with Gastric Biopsy in Algarve, Portugal
by
Aguieiras, Catarina
,
Cortez Nunes, Francisco
,
Louro, Ricardo
in
Amoxicillin
,
Analysis
,
Antibiotic resistance
2025
Background/Objectives: Helicobacter pylori (H. pylori) is a common gastric pathogen linked to gastritis, gastroduodenal ulcers, and gastric cancer. Rising antimicrobial resistance (AMR) poses challenges for effective treatment and has prompted the WHO to classify H. pylori as a high-priority pathogen. This study aimed to detect the prevalence of AMR genes in H. pylori-positive gastric samples from patients in Algarve, Portugal, where regional data is scarce. Methods: Eighteen H. pylori-positive gastric biopsy samples from patients undergoing upper gastrointestinal endoscopy were analyzed. PCR and sequencing were used to identify genes associated with resistance to amoxicillin (Pbp1A), metronidazole (rdxA, frxA), tetracycline (16S rRNA mutation) and clarithromycin (23S rRNA). Sequence identity and homologies were verified using tBLASTx and the Comprehensive Antibiotic Resistance Database (CARD). Results: Out of the 18 H. pylori-positive samples, 16 (88.9%) contained at least one AMR gene. The most frequent genes were rdxA (83.3%) and frxA (66.7%) for metronidazole resistance, and the 16S rRNA mutation (66.7%) for tetracycline. Resistance to amoxicillin and clarithromycin was detected in 27.8% and 16.7% of cases, respectively. Most samples (72.2%) had multiple resistance genes. A significantly strong association was found between female sex and the presence of the rdxA gene (p = 0.043). Conclusions: The study reveals a high prevalence of H. pylori resistance genes in Algarve, particularly against metronidazole and tetracycline. These findings highlight the need for local surveillance and tailored treatment strategies. Further research with larger populations is warranted to assess regional resistance patterns and improve eradication efforts.
Journal Article