Strategic Project - UI 709 - 2011-2012

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Organizational Unit

Publications

Gas-generating TPGS-PLGA microspheres loaded with nanoparticles (NIMPS) for co-delivery of minicircle DNA and anti-tumoral drugs

Publication . Gaspar, Vítor Manuel Abreu; Moreira, André; Costa, Elisabete C.; Queiroz, João; Sousa, Fani; Pichon, Chantal; Correia, Ilídio Joaquim Sobreira

Drug-DNA combination therapies are receiving an ever growing focus due to their potential for improving cancer treatment. However, such approaches are still limited by the lack of multipurpose delivery systems that encapsulate drugs and condense DNA simultaneously. In this study, we describe the successful formulation of gas-generating pH-responsive D-α-tocopherol PEG succinate-poly(d,l-lactic-co-glycolic acid) (TPGS-PLGA) hollow microspheres loaded with both Doxorubicin (Dox) and minicircle DNA (mcDNA) nanoparticles as a strategy to co-deliver these therapeutics. For this study mcDNA vectors were chosen due to their increased therapeutic efficiency in comparison to standard plasmid DNA. The results demonstrate that TPGS-PLGA microcarriers can encapsulate Dox and chitosan nanoparticles completely condense mcDNA. The loading of mcDNA-nanoparticles into microspheres was confirmed by 3D confocal microscopy and co-localization analysis. The resulting TPGS-PLGA-Dox-mcDNA nanoparticle-in-microsphere hybrid carriers exhibit a well-defined spherical shape and neutral surface charge. Microcarriers incubation in acidic pH produced a gas-mediated Dox release, corroborating the microcarriers stimuli-responsive character. Also, the dual-loaded TPGS-PLGA particles achieved 5.2-fold higher cellular internalization in comparison with non-pegylated microspheres. This increased intracellular concentration resulted in a higher cytotoxic effect. Successful transgene expression was obtained after nanoparticle-mcDNA co-delivery in the microspheres. Overall these findings support the concept of using nanoparticle-microsphere multipart systems to achieve efficient co-delivery of various drug-mcDNA combinations.

2015-07-09Journal article

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Levels of TBT and other selected organotin compounds in duplicate diet samples

Publication . Sousa, Ana C. A.; Coelho, Sónia; Pastorinho, M. Ramiro; Taborda Barata, Luis; Nogueira, António J.A.; Isobe, Tomohiko; Kunisue, Tatsuya; Takahashi, Shin; Shinsuke, Tanabe

Organotin compounds (OTs) are ubiquitous contaminants with a broad range of applications ranging from biocides and pesticides to catalysts for the production of polyurethane foams and silicones. The deleterious effects of some OTs (particularly tributyltin - TBT) upon wildlife and experimental animals are well documented and include endocrine disruption, immunotoxicity, neurotoxicity, genotoxicity and metabolic dysfunction in which obesity is included. However, virtually no data on the current human exposure levels is available. In order to bridge this gap, we quantified for the first time the levels of OTs in duplicate diet samples from members of the University of Aveiro in Portugal. OTs were detected in 32% of the 28 diet samples analyzed, at relatively low levels. TBT and monobutyltin were detected only in two samples and dibutyltin was detectable in three samples. Dioctyltin was quantified in four samples and monooctyltin in three samples. Phenyltins were below the detection limit in all the diet samples analyzed. Overall, for the vast majority of the samples (89%), the estimated daily intakes (EDI) of organotins through food were much lower than the established tolerable daily intakes (TDI). Hence, for the majority of the participants the risk associated with food ingestion is low.

2017-01-01Journal article

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Polyazamacrocycles as potential antitumor agents for human prostate cancer cells

Publication . Cruz, Carla; Cairrão, Elisa; Lourenço, Olga; Almeida, Paulo; Verde, Ignacio; Queiroz, João

Polyazamacrocycles are currently being studied and used in a variety of applications beyond their traditional place in supramolecular and co-ordination chemistry. This study suggests additional applications of these compounds with particular emphasis on their use as antiproliferative agents that could be potentially used to treat cancer. Four polyazamacrocycles were tested in human prostate cancer LNCaP and prostate epithelial PNTA1 cells to analyze changes in cell proliferation and cell death capabilities. Their intracellular localization was also evaluated by confocal microscopy. The results show a decrease in proliferation rate and cell viability of LNCaP and PNTA1, after treatment with these compounds. The decrease in the number of viable cells is similar for the majority of the compounds studied, and at higher concentration, the proliferation efficiency decreased significantly in the cell lines studied. Also, our results suggest that L and L2 induce early apoptosis in PNTA1 cells and late apoptosis/necrosis in LNCaP cells. The compounds did not induce a significant increase in necrosis of both cell types. Although the compounds did not localize in a unique organelle, all of them have as main target the Golgi apparatus and other localization profiles differed depending on the cell line.

2013-04Journal article

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Histopathological and in vivo evidence of regucalcin as a protective molecule in mammary gland carcinogenesis

Publication . Marques, Ricardo; Vaz, Cátia; Baptista, Cláudio; Gomes, Madalena; Gama, Adelina; Alves, Gilberto; Santos, Cecilia; Schmitt, Fernando; Socorro, Sílvia

Regucalcin (RGN) is a calcium-binding protein, which has been shown to be underexpressed in cancer cases. This study aimed to determine the association of RGN expression with clinicopathological parameters of human breast cancer. In addition, the role of RGN in malignancy of mammary gland using transgenic rats overexpressing the protein (Tg-RGN) was investigated. Wild-type (Wt) and Tg-RGN rats were treated with 7,12-dimethylbenz[α]anthracene (DMBA). Carcinogen-induced tumors were histologically classified and the Ki67 proliferation index was estimated. Immunohistochemistry analysis showed that RGN immunoreactivity was negatively correlated with the histological grade of breast infiltrating ductal carcinoma suggesting that progression of breast cancer is associated with loss of RGN. Tg-RGN rats displayed lower incidence of carcinogen-induced mammary gland tumors, as well as lower incidence of invasive forms. Moreover, higher proliferation was observed in non-invasive tumors of Wt animals comparatively with Tg-RGN. Overexpression of RGN was associated with diminished expression of cell-cycle inhibitors and increased expression of apoptosis inducers. Augmented activity of apoptosis effector caspase-3 was found in the mammary gland of Tg-RGN. RGN overexpression protected from carcinogen-induced mammary gland tumor development and was linked with reduced proliferation and increased apoptosis. These findings indicated the protective role of RGN in the carcinogenesis of mammary gland.

2015-01-15Journal article

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Synthesis and characterization of micelles as carriers of non-steroidal anti-inflammatory drugs (NSAID) for application in breast cancer therapy

Publication . Marques, João Filipe Gonçalves; Gaspar, Vítor Manuel Abreu; Costa, Elisabete C.; Paquete, Catarina; Correia, Ilídio Joaquim Sobreira

Non-steroidal anti-inflammatory drugs (NSAIDS) are emerging as a particularly valuable class of drugs due to their recently reported anti-tumoral activity in colorectal cancer. However, despite this tremendous potential, their bioavailability at the tumor microenvironment remains rather limited. To overcome this issue, in this work we synthesized biocompatible micellar nanocarriers composed of amphiphilic chitosan to deliver ibuprofen into breast cancer cells and evaluate its anti-tumor activity, while avoiding side-effects. Our results reveal that the formulations produced herein self-assembly into spherical micelles with suitable sizes for tumor accumulation (108–252 nm). Furthermore, by using a vortex-sonication method, ibuprofen was successfully encapsulated with high efficiency. Cell uptake studies show that ibuprofen-loaded micelles are readily internalized by tumor cells and deliver their cargo in the intracellular compartment as demonstrated by confocal microscopy images. This fact led to a remarkable reduction in cancer cell viability (<13%), at a relatively low drug dosage, illustrating the anti-tumoral activity of ibuprofen when delivered to breast cancer cells. These findings demonstrate the promising potential of chitosan micelles as carriers of cost-effective NSAIDS for application in breast cancer therapy.

2014-01-01Journal article

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