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Novel Hydrogel Membranes Based on the Bacterial Polysaccharide FucoPol
Publication . Araújo, Diana; Martins, Matilde; Concórdio-Reis, Patrícia; Roma-Rodrigues, Catarina; Morais, Maria; Alves, Vítor D.; Fernandes, Alexandra R.; Freitas, Filomena; UCIBIO - Applied Molecular Biosciences Unit; DQ - Departamento de Química; DCV - Departamento de Ciências da Vida; DCM - Departamento de Ciência dos Materiais; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); Molecular Diversity Preservation International (MDPI)
FucoPol, a fucose-rich polyanionic polysaccharide, was used for the first time for the preparation of hydrogel membranes (HMs) using Fe3+ as a crosslinking agent. This study evaluated the impact of Fe3+ and FucoPol concentrations on the HMs’ strength. The results show that, above 1.5 g/L, Fe3+ concentration had a limited influence on the HMs’ strength, and varying the FucoPol concentration had a more significant effect. Three different FucoPol concentrations (1.0, 1.75 and 2.5 wt.%) were combined with Fe3+ (1.5 g/L), resulting in HMs with a water content above 97 wt.% and an Fe3+ content up to 0.16 wt.%. HMs with lower FucoPol content exhibited a denser porous microstructure as the polymer concentration increased. Moreover, the low polymer content HM presented the highest swelling ratio (22.3 ± 1.8 g/g) and a lower hardness value (32.4 ± 5.8 kPa). However, improved mechanical properties (221.9 ± 10.2 kPa) along with a decrease in the swelling ratio (11.9 ± 1.6 g/g) were obtained for HMs with a higher polymer content. Furthermore, all HMs were non-cytotoxic and revealed anti-inflammatory activity. The incorporation of FucoPol as a structuring agent and bioactive ingredient in the development of HMs opens up new possibilities for its use in tissue engineering, drug delivery and wound care management.
Gold nanoparticles for iRNA: inhibition of intercellular communication mediated by cancer cells derived exosomes
Publication . Cardoso, Fátima Isabel Gomes; Roma-Rodrigues, Catarina; Baptista, Pedro
Inter-cellular communication has been associated with the transference of molecular information mediated by exosomes, which is particularly relevant in cancer metastasis. Exosomes’ integrin α6β1 and α6β4, overexpressed in breast cancer, specifically bind to fibroblasts and epithelial cells in the lung, activating tyrosine-protein kinase (Src) and upregulating pro-inflammatory S100 genes. This interaction will ultimately promote lung tropic metastasis. Herein, we used antisense oligonucleotides (ASO) vectorized by gold nanoparticles to silence the ITGA6 gene, which codifies for the α6 integrin, in the breast adenocarcinoma cell lines. Subsequently, the internalization of the exosomes secreted by the silenced cells (primary cells) was examined in secondary cells. The downregulation of ITGA6 gene and protein in cells and exosomes was assessed by RT-qPCR, Western Blot and ELISA, respectively. Internalization of those exosomes
by secondary cells will be evaluated to understand the effect of integrin silencing in tumor progression and in the formation of metastasis.
Doxorubicin-sensitive and -resistant colorectal cancer spheroid models
Publication . Valente, Ruben; Cordeiro, Sandra; Luz, André; Rodrigues, Catarina Roma; Baptista, Pedro V.; Fernandes, Alexandra R.; DCV - Departamento de Ciências da Vida; UCIBIO - Applied Molecular Biosciences Unit; Frontiers Media
Introduction: The research on tumor microenvironment (TME) has recently been gaining attention due to its important role in tumor growth, progression, and response to therapy. Because of this, the development of three-dimensional cancer models that mimic the interactions in the TME and the tumor structure and complexity is of great relevance to cancer research and drug development. Methods: This study aimed to characterize colorectal cancer spheroids overtime and assess how the susceptibility or resistance to doxorubicin (Dox) or the inclusion of fibroblasts in heterotypic spheroids influence and modulate their secretory activity, namely the release of extracellular vesicles (EVs), and the response to Dox-mediated chemotherapy. Different characteristics were assessed over time, namely spheroid growth, viability, presence of hypoxia, expression of hypoxia and inflammation-associated genes and proteins. Due to the importance of EVs in biomarker discovery with impact on early diagnostics, prognostics and response to treatment, proteomic profiling of the EVs released by the different 3D spheroid models was also assessed. Response to treatment was also monitored by assessing Dox internalization and its effects on the different 3D spheroid structures and on the cell viability. Results and Discussion: The results show that distinct features are affected by both Dox resistance and the presence of fibroblasts. Fibroblasts can stabilize spheroid models, through the modulation of their growth, viability, hypoxia and inflammation levels, as well as the expressions of its associated transcripts/proteins, and promotes alterations in the protein profile exhibit by EVs. Summarily, fibroblasts can increase cell-cell and cell-extracellular matrix interactions, making the heterotypic spheroids a great model to study TME and understand TME role in chemotherapies resistance. Dox resistance induction is shown to influence the internalization of Dox, especially in homotypic spheroids, and it is also shown to influence cell viability and consequently the chemoresistance of those spheroids when exposed to Dox. Taken together these results highlight the importance of finding and characterizing different 3D models resembling more closely the in vivo interactions of tumors with their microenvironment as well as modulating drug resistance.
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SFRH/BPD/124612/2016