Browsing by Author "Guerreiro, Susana G."
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- Application of gold nanoparticles as radiosensitizer for metastatic prostate cancer cell linesPublication . Soares, Sílvia; Faria, Isabel; Aires, Fátima; Monteiro, Armanda; Pinto, Gabriela; Sales, Maria Goreti; Correa-Duarte, Miguel A.; Guerreiro, Susana G.; Fernandes, RúbenMore than 50% of all prostate cancer (PCa) patients are treated by radiotherapy (RT). Radioresistance and cancer recurrence are two consequences of the therapy and are related to dose heterogeneity and non-selectivity between normal and tumoral cells. Gold nanoparticles (AuNPs) could be used as potential radiosensitizers to overcome these therapeutic limitations of RT. This study assessed the biological interaction of different morphologies of AuNPs with ionizing radiation (IR) in PCa cells. To achieve that aim, three different amine-pegylated AuNPs were synthesized with distinct sizes and shapes (spherical, AuNPsp-PEG, star, AuNPst-PEG, and rods, AuNPr-PEG) and viability, injury and colony assays were used to analyze their biological effect on PCa cells (PC3, DU145, and LNCaP) when submitted to the accumulative fraction of RT. The combinatory effect of AuNPs with IR decreased cell viability and increased apoptosis compared to cells treated only with IR or untreated cells. Additionally, our results showed an increase in the sensitization enhancement ratio by cells treated with AuNPs and IR, and this effect is cell line dependent. Our findings support that the design of AuNPs modulated their cellular behavior and suggested that AuNPs could improve the RT efficacy in PCa cells.
- GLP-1R and IL-6 expression in the gastrointestinal tract of a murine model of metabolic syndromePublication . Costa, José; Oliveira, Sofia; Pereira, Ana Cláudia; Soares, Raquel; Baylina, Pilar; Guerreiro, Susana G.; Fernandes, Rúben; Luís, CarlaGlucose homeostasis is a critical cornerstone in both health and disease. It is described to be regulated by the balance of insulin and glucagon secretion but, this bi-hormonal perspective is long overdue, since glucose homeostasis is now known to be a multi-hormonal process. Metabolic syndrome (MetS) is a cluster of metabolic features which includes impaired glucose metabolism and obesity. Obesity promotes a low chronic inflammation state due to release of bioactive molecules like cytokines, ultimately contributing to cardiovascular disease, diabetes and cancer. The gastrointestinal tract (GIT), namely stomach and intestine, has a vital role not only in the food uptake and absorption, but also in the production of incretin hormones, such as GLP-1. We aim to evaluate the GLP-1 receptor (GLP-1R) in the GIT of a MetS animal model, and to assess whether it correlates with inflammatory levels. The expression of GLP-1R and Interleukin-6 (IL-6) was evaluated in the stomach and intestine of mice subjected to Normal Diet (ND) and High Fat Diet (HFD) by immunohistochemistry. We observed that HFD fed animals presented lower levels of GLP-1R in stomach and intestine when compared with animals fed with ND. Concomitantly, these mice expressed increased levels of IL-6. GLP-1R expression is inversely correlated with the expression of the proinflammatory cytokine IL-6.
- Melanoma and obesity: Should antioxidant vitamins be addressed?Publication . Oliveira, Sofia; Coelho, Pedro; Prudêncio, Cristina; Vieira, Mónica; Soares, Raquel; Guerreiro, Susana G.; Fernandes, RúbenMelanoma is an aggressive form of skin cancer refractory to conventional therapies. Obesity has reached epidemic dimensions acting as a risk factor for several cancer types, such as melanoma. Several reactive species of oxygen are also involved in melanoma initiation and progression. Low levels of antioxidant content and/or activity in lightly pigmented cells could expose them to an extremely oxidative environment and rise the susceptibility to oxidative damage and consequently loss of cell homeostasis. Despite the knowledge about melanoma biology, pathogenesis and developed therapies, is extremely important to understand the antioxidant modulation of melanoma under an environment of obesity, especially the effect of some natural compounds of the diet, such as antioxidant vitamins A, C and E and selenium in order to establish alternatives to conventional therapies, which are known to be ineffective against melanoma.
- Mesenchymal Stem Cells (MSCs) as a potential therapeutic Strategy in COVID-19 Patients: Literature ResearchPublication . Coelho, André; Alvites, Rui Damásio; Branquinho, Mariana Vieira; Guerreiro, Susana G.; Maurício, Ana ColetteIn 2019, an outbreak of an unknown coronavirus – SARS-CoV-2 – responsible for COVID-19 disease, was first reported in China, and evolved into a pandemic of huge dimensions and raised serious concerns for global health. The number of critical cases continues to increase dramatically, while vaccines and specific treatments are not yet available. There are several strategies currently being studied for the treatment of adverse symptoms of COVID-19, that encompass Acute Lung Injury (ALI)/Acute Respiratory Distress Syndrome (ARDS), extensive pulmonary inflammation, cytokine storm, and pulmonary edema, due to virus-induced pneumonia.
- Optical immunosensor panel using quantum dot-antibody conjugates for highly sensitive detection of carbohydrate antigen 19–9 (CA19-9)Publication . Oliveira, Daniela; Oliveira, Pedro; Xu, Ana; Rodrigues, Eduarda; Guerreiro, Susana G.; Castro, Rafael C.; Ribeiro, David S. M.; Santos, João L. M.; Piloto, Ana Margarida L.This study introduces a fluorescent immunosensor colour panel with antibody-conjugated quantum dots for detecting CA19-9 in human serum. The immunosensors presented decreasing fluorescence with increasing CA19-9 concentrations, with a linear detection range from 0.01 to 501.87 U mL−1 and detection limits of 1.66 × 10⁻⁴, 2.71 × 10⁻⁴, and 5.45 × 10⁻⁴ U mL−1 for the green-, orange-, and red-emitting conjugates in human serum. These limits are well below the 37 U mL−1 cutoff for early pancreatic cancer risk. The immunosensor panel is simple, sensitive, and specific, offering a visual colour readout for rapid CA19-9 detection, making it ideal for point-of-care applications. The results highlight the potential of the developed conjugates as a sensitive fluorescence colour panel for detecting CA19-9 across a wide range in human serum, both below and above the pancreatic cancer cutoff. With just 200 μL of sample and a single pre-filtration step, the assay delivers results in under 15 min, offering a cost-effective and efficient platform for point-of-care use.
- Regeneration in the Podarcis bocagei model organism: a comprehensive immune-/histochemical analysis of the tailPublication . Luís, Carla; Rodrigues, llda; Guerreiro, Susana G.; Fernandes, Rúben; Soares, RaquelRegeneration is the process of regrowth of an injured/missing tissue/organ from the residual tissue. One outstanding example is the regeneration of tail in lizards in which they can completely regenerate without the formation of scaring or fibrotic tissue. This study presents an analysis of the main differences between a mature regenerated tail and the original tail of the lizard Podarcis bocagei by comparing histological biomarkers for support structures, morphology and pigmentation, vasculature and energy storage. Matured regenerated and original tails were studied with different histological staining’s and immunohistochemistry to highlight the various tissue components. We found differences in the morphological features scalation pattern and pigmentation, as well as in the support structures: muscle organization, collagen and calcification. Vasculature was remodeled. Energy storage was restored with regeneration maintaining therefore the main metabolic function. We demonstrate that the regenerated tail does not lose its main functions like locomotion and energy metabolism. The present findings may open a new window of research with implications in regenerative medicine.