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- 3-Bromopyruvate boosts the effect of chemotherapy in acute myeloid leukemia by a pro-oxidant mechanismPublication . Vieira, Joana Pereira; Preto, Ana; Granja, Sara; Queirós, Odília; Celeiro, Sónia Pires; Ko, Young Hee; Casal, Margarida; Matos, Catarina Barbosa; Baltazar, Fátima; Granja, SaraAcute myeloid leukemia (AML) comprises a diverse group of blood cancers with varying genetic, phenotypic, and clinical traits, making development of targeted therapy challenging. Metabolic reprogramming in AML has been described as relevant for chemotherapy effectiveness. 3-Bromopyruvate (3-BP) is an anticancer agent that undermines energy metabolism of cancer cells. However, the effect of 3-BP in hematologic malignancies, such as AML, needs further investigation. Thus, we aimed to explore 3-BP as a chemo-sensitizing agent in AML. Different approaches of combining 3-BP with classical chemotherapy (daunorubicin and cytarabin) were tested in diverse AML cell lines. Cell sensitivity to the different drug combinations was analyzed by Trypan blue staining. The effect of pre-treatment with a non-toxic concentration of 3-BP was assessed on the AML cell metabolic profile (Western blot and immunofluorescence), mitochondrial activity (cytometry flow), and antioxidant capacity (colorimetric detection kit). KG-1 and MOLM13 cells showed increased sensitivity to chemotherapy (decreased EC 50 values) after exposure to a non-toxic concentration (5 μ M) of 3-BP. In both cell lines, 5 glucose consumption without changing extracellular lactate levels. 5 μ μ M 3-BP decreased M 3-BP treatment increased reactive oxygen species levels and decreased cell antioxidant capacity by depleting reduced glutathione levels in both KG-1 and MOLM13 cells. Our results demonstrate that non-toxic concentrations of 3-BP enhance the effect of classical chemotherapy in AML cells through a pro-oxidant mechanism. These data unveiled a new approach for AML treatment, using 3-BP or other pro-oxidant agents as co-adjuvants of chemotherapy, subsiding chemotherapy- induced side effects.
- 3-Nitrotyrosine quantification methods: Current concepts and future challengesPublication . Teixeira, Dulce; Fernandes, Rúben; Prudêncio, Cristina; Vieira, MónicaMeasurement of 3-nitrotyrosine (3-NT) in biological samples can be used as a biomarker of nitrosative stress, since it is very stable and suitable for analysis. Increased 3-NT levels in biological samples have been associated with several physiological and pathological conditions. Different methods have been described for the detection and quantification of this molecule, such as (i) immunological methods; (ii) liquid chromatography, namely high-pressure liquid chromatography (HPLC)-based methods that use ultraviolet-visible (UV/VIS) absorption, electrochemical (ECD) and diode array (DAD) detection, liquid chromatography-mass spectrometry (LC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS); (iii) gas chromatography, such as gas chromatography-mass spectrometry (GC-MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS). Methods A literature review on nitrosative stress, protein nitration, as well as 3-NT quantification methods was carried out. Results This review covers the different methods for analysis of 3-NT that have been developed during the last years as well as the latest advances in this field. Overall, all methods present positive and negative aspects, although it is clear that chromatography-based methods present good sensitivity and specificity. Regarding this, GC-based methods exhibit the highest sensibility in the quantification of 3-NT, although it requires a prior time consuming derivatization step. Conversely, HPLC does not require such derivatization step, despite being not as accurate as GC. Conclusion It becomes clear that all the methods described during this literature review, although accurate for 3-NT quantification, need to be improved regarding both sensitivity and specificity. Moreover, optimization of the protocols that have been described is clearly needed.
- Adipocyte secretome increases radioresistance of malignant melanocytes by improving cell survival and decreasing oxidative statusPublication . Coelho, Pedro; Silva, Liliana; Faria, Isabel; Vieira, Mónica; Monteiro, Armanda; Pinto, Gabriela; Prudêncio, Cristina; Fernandes, Rúben; Soares, RaquelRadiotherapy is a treatment option for the majority of malignancies. However, because melanoma is known to be radioresistant, the use of ionizing radiation as an adjuvant therapy in cutaneous melanoma patients is ineffective. Obesity has now been recognized as a risk factor for melanoma. High adiposity is generally associated with a more pro-oxidative status. Oxidative stress is a major player in radiation therapy and also a common link between obesity and cancer. Several adipocyte-released proteins are known to have a role in controlling cellular growth and pro-survival signaling. For that reason, we investigated the influence of 3T3-L1 mature adipocyte secretome in B16-F10 malignant melanocyte radiosensitivity. We evaluated B16-F10 cell survival and redox homeostasis when exposed to four daily doses of ionizing radiation (2 Gy per day) up to a total of 8 Gy in a medical linear accelerator. B16-F10 melanocytes exhibited slight alterations in survival, catalase activity, nitrative stress and total oxidant concentration after the first 2 Gy irradiation. The motility of the melanocytes was also delayed by ionizing radiation. Subsequent irradiations of the malignant melanocytes led to more prominent reductions in overall survival. Remarkably, 3T3-L1 adipocyte-secreted molecules were able to increase the viability and migration of melanocytes, as well as lessen the pro-oxidant burden induced by both the single and cumulative X-ray doses. In vitro adipocyte-released factors protected B16-F10 malignant melanocytes from both oxidative stress and loss of viability triggered by radiation, enhancing the radioresistant phenoyype of these cells with a concomitant activation of the AKT signaling pathway These results both help to elucidate how obesity influences melanoma radioresistance and support the usage of conventional medical linear accelerators as a valid model for the in vitro radiobiological study of tumor cell lines.
- Alkali metals levels in the human brain tissue: Anatomical region differences and age-related changesPublication . Ramos, Patrícia; Santos, Agostinho; Pinto, Edgar; Pinto, Nair Rosas; Mendes, Ricardo; Magalhães, Teresa; Almeida, AgostinhoThe link between trace elements imbalances (both "toxic" and "essential") in the human brain and neurodegenerative disease has been subject of extensive research. More recently, some studies have highlighted the potential role of the homeostasis deregulation of alkali metals in specific brain regions as key factor in the pathogenesis of neurodegenerative diseases such as multiple sclerosis and Alzheimer's disease. Using flame atomic emission spectrometry and inductively coupled plasma-mass spectrometry after microwave-assisted acid digestion of the samples, alkali metals (Na, K, Li, Rb and Cs) were determined in 14 different areas of the human brain (frontal cortex, superior and middle temporal gyri, caudate nucleus, putamen, globus pallidus, cingulated gyrus, hippocampus, inferior parietal lobule, visual cortex of the occipital lobe, midbrain, pons, medulla and cerebellum) of adult individuals (n=42; 71±12, range: 50-101 years old) with no known history and evidence of neurodegenerative, neurological or psychiatric disorder. Potassium was found as the most abundant alkali metal, followed by Na, Rb, Cs and Li. Lithium, K and Cs distribution showed to be quite heterogeneous. On the contrary, Rb and Na appeared quite homogeneously distributed within the human brain tissue. The lowest levels of Na, K, Rb and Li were found in the brainstem (midbrain, medulla and pons) and cerebellum, while the lowest levels of Cs were found in the frontal cortex. The highest levels of K (mean±sd; range 15.5±2.5; 8.9-21.8mg/g) Rb (17.2±6.1; 3.9-32.4μg/g and Cs (83.4±48.6; 17.3-220.5ng/g) were found in putamen. The highest levels of Na and Li were found in the frontal cortex (11.6±2.4; 6.6-17.1mg/g) and caudate nucleus (7.6±4.6 2.2-21.3ng/g), respectively. Although K, Cs and Li levels appear to remain largely unchanged with age, some age-related changes were observed for Na and Rb levels in particular brain regions (namely in the hippocampus).
- Altered NRF2 signalling in systemic redox imbalance: Insights from non-communicable diseasesPublication . Santos, Marlene; Morgenstern, Christina; Santos, MarleneThe balanced activity of the cytoprotective transcription factor NRF2 is central for maintaining redox, metabolic-energetics, and proteome homeostasis, as well as for regulating inflammatory responses, among other functions. Activated NRF2 regulates the expression of hundreds of genes containing antioxidant response elements (AREs) or electrophile response elements (EpRE) in their regulatory regions, often promoting cytoprotection under stress conditions and contributing to defence against various pathologies and non-communicable diseases (NCDs). The products of increased NRF2 activity, detected systemically, may originate from either the white blood cells, the cells of the vasculature or tissue-derived products that could be secreted into biological fluids. Therefore, assessing basal and inducible NRF2 activity in blood or other biofluids is crucial for inferring NRF2 responses in local and often inaccessible tissues. In previous work, we identified a panel of six biomarkers - Glutamate-cysteine ligase catalytic subunit (GCLC), Glutamate-cysteine ligase modifier subunit (GCLM), Haem oxygenase 1 (HMOX1), NAD(P)H quinone dehydrogenase 1 (NQO1), Sulfiredoxin 1 (SRXN1), and Thioredoxin reductase 1 (TXNRD1) - as indicators of NRF2 activity. In the current study, we assess their utility in a clinical setting to measure NRF2 activation in a disease context. Here we discuss findings on how NRF2 activity in accessible human samples can reveal its involvement in various NCDs and its connection to clinical aspects such as diagnosis, disease progression and response to therapy.
- An overview of the recent advances in antimicrobial resistancePublication . Oliveira, Manuela; Antunes, Wilson; Mota, Salete; Carvalho, Áurea Madureira; Oliveira, Ricardo Jorge Dinis; Silva,Diana Dias daAntimicrobial resistance (AMR), frequently considered a major global public health threat, requires a comprehensive understanding of its emergence, mechanisms, advances, and implications. AMR’s epidemiological landscape is characterized by its widespread prevalence and constantly evolving patterns, with multidrug-resistant organisms (MDROs) creating new challenges every day. The most common mechanisms underlying AMR (i.e., genetic mutations, horizontal gene transfer, and selective pressure) contribute to the emergence and dissemination of new resistant strains. Therefore, mitigation strategies (e.g., antibiotic stewardship programs—ASPs—and infection prevention and control strategies—IPCs) emphasize the importance of responsible antimicrobial use and surveillance. A One Health approach (i.e., the interconnectedness of human, animal, and environmental health) highlights the necessity for interdisciplinary collaboration and holistic strategies in combating AMR. Advancements in novel therapeutics (e.g., alternative antimicrobial agents and vaccines) offer promising avenues in addressing AMR challenges. Policy interventions at the international and national levels also promote ASPs aiming to regulate antimicrobial use. Despite all of the observed progress, AMR remains a pressing concern, demanding sustained efforts to address emerging threats and promote antimicrobial sustainability. Future research must prioritize innovative approaches and address the complex socioecological dynamics underlying AMR. This manuscript is a comprehensive resource for researchers, policymakers, and healthcare professionals seeking to navigate the complex AMR landscape and develop effective strategies for its mitigation.
- Análise da rotulagem de suplementos alimentares utilizados no Sistema Nervoso CentralPublication . Ferreira, Liliana; Cruz, Agostinho; Oliveira, Ana Isabel; Ferraz Oliveira, Rita; Pinho, CláudiaOs suplementos alimentares têm diversos benefícios demonstrados. No entanto, a crença errónea por parte dos consumidores de que estes são isentos de risco e as obrigações legais requeridas para a sua entrada no mercado têm servido de alerta para a necessidade de mais investigação. Analisar, do ponto de vista legal e científico, a informação disponibilizada na rotulagem de suplementos alimentares à base de plantas utilizados para problemas associados ao Sistema Nervoso, comercializados em Portugal. Estudo descritivo, observacional, transversal com a recolha de 44 rótulos de suplementos comercializados em Farmácias Comunitárias e em Ervanárias/Lojas Dietéticas da cidade de Vila Nova de Famalicão, entre julho e agosto de 2019, em formulário próprio. Do ponto de vista legal, a maioria dos SA analisados cumpriu as menções obrigatórias na rotulagem. Do ponto de vista científico, o nome científico das plantas foi a informação que mais frequentemente está presente na rotulagem, com 97,7%. A padronização dos extratos (29,5%), as interações (11,4%) e as reações adversas (11,4%) foram as informações menos mencionadas. Os resultados obtidos realçam a necessidade de uma maior atenção quanto às informações existentes na rotulagem dos suplementos, no sentido de permitir aos consumidores um uso informado e seguro dos produtos.
- Antioxidant Activity and Cytotoxicity of Taraxacum hispanicum Aqueous and Ethanolic Extracts on HepG2 CellsPublication . Laranjeira, C.; Nogueira, A.; Almeida, R.; Oliveira, Ana; Ferraz Oliveira, Rita; Pinho, Cláudia; Cruz, AgostinhoPlants belonging to the genus Taraxacum have been used in traditional medicine. Nowadays, extracts of these plants have been reported for the treatment of diseases, including liver disorders. Increasing interest and research on these plants also revealed its potential for treating cancer. This study aims to evaluate the antioxidant activity and cytotoxic properties of crude extracts from aerial parts of Taraxacum hispanicum H.Lindb, against human hepatocarcinoma (HepG2). Material and methods: Evaluation of the antioxidant properties was performed using DPPH in vitro test, superoxide scavenging assay and Fe2+ chelating activity. MTT assay was used to determine metabolic activity, for 24 and 48 hours.
- Application of CytoPath®easy vials in Cervical Cancer screening: Self‑sampling approachPublication . Fernandes, Sílvia P. M.; Vilarinho, Ana Sofia; Frutuoso, Amaro; Teixeira, Cidália; Silva, Regina Augusta A. P."CytoPath®Easy kit (DiaPath S.p.A.) offers a major advantage compared to other commercially available kits available for the screening of cervical cancer, as it does not require additional equipment for sample processing. Using this methodology, collected epithelial cells are immersed in a preservative liquid before setting as a thin layer on a slide via gravity sedimentation. Aims: To evaluate the suitability of the CytoPath®Easy kit for the processing of cervicalsamples, detection of pre‑neoplastic lesions, and nucleic preservation and extraction for HR‑HPV diagnosis. A total of 242 self‑sampled cervicalspecimens were utilized, with 192 collected in CytoPath®Easy vials and 50 collected and processed using the ThinPrepTM for comparative analysis. The samples underwent processing, Papanicolaou staining, and microscopic evaluation for morphological parameters. The extracted nucleic acids were assessed for purity and integrity, and the detection of high‑risk human papillomavirus (HR‑HPV) was carried out using the Alinitym HR HPV system kit (Abbott Laboratórios Lda). Both methods demonstrated effective performance, enabling the morphological assessment of the cervical epithelium. Statistical analysis indicated that ThinPrepTM yielded significantly better results in terms of cellularity. Conversely, CytoPath®Easy exhibited superior performance in terms of the quantity of extracted DNA and its degree of purification. Concerning the time consumed during processing, both methods were comparable, with the CytoPath®Easy methodology standing out for its cost‑effectiveness, as it does not necessitate additional instruments and consumables. The novel CytoPath®Easy methodology proves effective in preserving both nucleic acids and cell morphology characteristics, two crucial features for cervical cancer screening."
- Application of real-time PCR in the assessment of the toxic cyanobacterium cylindrospermopsis raciborskii abundance and toxicological potentialPublication . Moreira, Cristiana; Martins, António; Azevedo, Joana; Freitas, Marisa; Regueiras, Ana; Vale, Micaela; Antunes, Agostinho; Vasconcelos, VítorCyanobacteria are prokaryotic photosynthetic microorganisms that pose a serious threat to aquatic environments because they are able to form blooms under eutrophic conditions and produce toxins. Cylindrospermopsis raciborskii is a planktonic heterocystous filamentous cyanobacterium initially assigned to the tropics but currently being found in more temperate regions such as Portugal, the southernmost record for this species in Europe. Cylindrospermopsin originally isolated from C. raciborskii is a cytotoxic alkaloid that affects the liver, kidney, and other organs. It has a great environmental impact associated with cattle mortality and human morbidity. Aiming in monitoring this cyanobacterium and its related toxin, a shallow pond located in the littoral center of Portugal, Vela Lake, used for agriculture and recreational purposes was monitored for a 2-year period. To accomplish this, we used the real-time PCR methodology in field samples to quantify the variation of specific genetic markers with primers previously described characterizing total cyanobacteria (16S rRNA), C. raciborskii (rpoC1), and cylindrospermopsin synthetase gene (pks). The results report the high abundance of both cyanobacteria and C. raciborskii in Vela Lake, with C. raciborskii representing 0.4% to 58% of the total cyanobacteria population. Cylindrospermopsin synthetase gene was detected in one of the samples. We believe that with the approach developed in this study, it will be possible to monitor C. raciborskii population dynamics and seasonal variation, as well as the potential toxin production in other aquatic environments.