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Publications

Selective cytotoxicity and cell death induced by human amniotic membrane in hepatocellular carcinoma

Publication . Mamede, Ana Catarina Manjolinha; Guerra, S; Laranjo, Marta; Carvalho, Maria J; Oliveira, R C; Gonçalves, A C; Alves, R; Castro, L Prado; Ribeiro, A B Sarmento; Moura, P; Abrantes, Ana M; Maia, C J; Botelho, M F

Hepatocellular carcinoma (HCC) has a worldwide high incidence and mortality. For this reason, it is essential to invest in new therapies for this type of cancer. Our team already proved that human amniotic membrane (hAM) is able to inhibit the metabolic activity of several human cancer cell lines, including HCC cell lines. Taking into account the previously performed work, this experimental study aimed to investigate the pathways by which hAM protein extracts (hAMPEs) act on HCC. Our results showed that hAMPE reduce the metabolic activity, protein content and DNA content in a dose- and time-dependent manner in all HCC cell lines. This therapy presents selective cytotoxicity, since it was not able to inhibit a non-tumorigenic human cell line. In addition, hAMPE induced cell morphology alterations in all HCC cell lines, but death type is cell line dependent, as proved by in vitro and in vivo studies. In conclusion, hAMPE have a promising role in HCC therapy, since it is capable of inducing HCC cytotoxicity and cell death.

2015-12Journal article

Restricted access

miRNA-29 bioseparation and target delivery strategies for Alzheimer's disease

Publication . Pereira, Patrícia Alexandra Nunes; Sousa, Fani Pereira de; Figueiras, Ana Rita; Correia, Ilídio Joaquim Sobreira

The possibility of selectively alter the expression pattern of a particular gene has been sought by scientists and clinicians for a long time. Nowadays, RNA interference (RNAi)-based technology has become a novel tool for silencing gene expression in cells. In addition, this strategy encloses an enormous therapeutic potential that could change the course of the currently applied treatments in several life threatening pathologies and it is expected that this technology can be translated onto clinical applications in a near future. MicroRNA (miRNA) has become a commonly employed tool for gene silencing, since it prevents protein synthesis by inducing the messenger RNA (mRNA) degradation, with a high specificity degree. Consequently, in the last years, the miRNAs have emerged as biopharmaceuticals to regulate several pathways involved in the insurgence and progression of the Alzheimer’s disease (AD), since they might have key regulatory roles in many neuronal functions, such as differentiation, synaptic plasticity and memory formation, and typically they are down-regulated in disease conditions. In the literature there are some studies describing a causal relationship between miR-29 expression and AD, since a loss of miR-29 cluster can contribute to increased beta-amyloid precursor protein-converting enzyme 1 (BACE1) and Amyloid-β (Aβ) levels in sporadic AD patients. Thus, this evidence supports the possibility to use miR-29 as a potential therapeutic target for AD therapy. In general, miRNA-based therapy relies on the use of synthetic microRNAs. However, these synthesized formulations typically present contaminants that can lead to non-targeted gene silencing, which still restricts the pre-clinical or clinical application of these RNAs. Thus, considering this therapeutic purpose and the global distribution of novel biopharmaceuticals it is necessary to develop efficient processes for their preparation. The development of new strategies for microRNA production with high purity degree and biologically active is extremely required. One of the strategies might be the use of the recombinant production of biomolecules using prokaryotic hosts. Hence, the present work intends to develop and establish an integrative biotechnological platform to biosynthesize and purify a recombinant miRNA precursor (pre-miR-29b) to act in the selective silencing of endogenous pathways directly related with AD, in particular BACE1 and Aβ. In addition, the success of these therapies also depends upon the ability to selectively and efficiently deliver the pre-miR-29b in the cytoplasmic compartment of neuronal cells, the location where their function is exerted; therefore the development of miRNA delivery systems was also envisioned. The expression system Rhodovulum sulfidophilum (R. sulfidophilum) DSM 1374 allowed, for the first time, the production of human pre-miR-29b with a straightforward recuperation of pre-miR-29b in a single step, maintaining its biological active form. The application of this recombinant bacterial microorganism is innovative and is supported by the unusual capacity of secreting the nucleic acids to the extracellular space and the absence of host ribonucleases in the culture medium. Therefore, it is expected that the secreted miRNA will be devoid of main bacterial associated impurities. Regarding the growth conditions, and conversely to what was previously described for this bacterium, our results showed to be possible to develop an original approach for the aerobic growth of the R. sulfidophilum, which results in a cell growth improvement followed by an enhanced production of human pre-miR-29b. The extracellular pre-miR-29b concentration was approximately 182 μg/L, after 40 hours of bacterial growth and the total intracellular pre-miR-29b was of about 358 μg/L, at 32 hours of cell growth. To further develop a potential therapeutic application, the major interest is not only to produce high quantities of RNA but also to obtain and preserve its biological active form, fulfilling the requirements of regulatory agencies. Hence, to assure that this prerequisite is met it was used a novel and effective purification strategy, based on affinity chromatography, to purify the pre-miR-29b. Therefore, in order to achieve the selectivity towards the target pre-miRNA and the maximum resolution between the pre-miR-29b and other host biomolecules (transfer RNAs and proteins) it was used an affinity support that exploits the same biological interactions that are established within the cell, by using immobilized amino acids (L-lysine and L-arginine), as specific ligands. The recognition of the pre-miR-29b achieved with these supports, allowed its selective recovery from a complex mixture with high efficiency and high purity. In parallel, the binding of pre-miRNA to these different amino acids was studied by Surface Plasmon Resonance. This information brings important insights concerning the characterization of the pre-miRNA binding onto chromatographic supports. Moreover, it was possible to determine some particular conditions enabling the improvement of the binding specificity of the amino acid ligands used to purify miRNA, preserving the RNA integrity. Taking into account that the structure of the chromatographic supports has been continuously developed to afford rapid and efficient separations, namely for the purification of nucleic acids, it was also tested a monolithic support to purify the pre-miR-29b. The association of the high capacity of these supports with the specificity conferred by the agmatine ligand (a derivative of L-arginine) represented a novelty and an advantage to obtain highly pure pre-miR-29b (90%) with a high recovery yield (95%). The establishment of an effective application of miRNAs is usually constrained by different phenomena, namely their easy degradation when in contact with the body fluids. To overcome this limitation, delivery systems, such as polymeric systems (polyplexes), were developed and characterized in order to encapsulate and protect the pre-miR-29b biopharmaceuticals from degradation, allowing their sustained and targeted release. The formulations prepared with chitosan and polyethylenimine demonstrated high loading capacity, small sizes and exhibited a strong positive charge on their surface. In addition, considering the application field of this work, the delivery systems should also have the ability to penetrate the Blood-Brain Barrier (BBB), causing an increase of the pre-miRNAs concentration in the brain and, consequently the improvement of the therapeutic effect. Actually, BBB is an intrinsic barrier limiting miRNA therapeutic effect on the central nervous system. Thus, to improve the delivery of pre-miRNA therapeutics in the brain, the polyplexes were functionalized with specific ligands, namely lactoferrin and stearic acid which are recognized by cell surface receptors of BBB. Finally, it was evaluated the biological activity of the recombinant pre-miR-29b by measuring the efficiency on human BACE1 knockdown, using in vitro neuronal cell lines. The effect of recombinant pre-miR-29b administration was verified by both assessing the mRNA and protein human BACE1 levels, by using RT-qPCR, Western blot and Imunocytochemistry. Results suggest that recombinant pre-miR-29b can represent a novel biopharmaceutical product for the therapeutic modulation of human BACE1 levels, because high levels of inhibition were achieved, namely 80% of reduction for BACE1 protein expression and 45% for Aβ42 levels. Globally, the implementation of these cutting-edge technologies can have a great impact on the biopharmaceutical industry, providing the basis for the implementation of novel miRNA-based therapeutics, not only for neurological disorders but also for future therapeutic targets that can be of potential interest.

2016Doctoral thesis

Open access

Oxidative Stress, DNA, Cell Cycle/Cell Cycle Associated Proteins and Multidrug Resistance Proteins: Targets of Human Amniotic Membrane in Hepatocellular Carcinoma

Publication . Mamede, Ana Catarina Manjolinha; Guerra, S; Laranjo, Marta; Santos, K; Carvalho, Maria J; Carvalheiro, Tiago; Moura, P; Paiva, A; Abrantes, Ana M; Baptista, Cláudio; Botelho, M F

The anticancer effects of human amniotic membrane (hAM) have been studied over the last decade. However, the action mechanisms responsible for these effects are not fully understood until now. Previously results reported by our team proved that hAM is able to induce cytotoxicity and cell death in hepatocellular carcinoma (HCC), a worldwide high incident and mortal cancer. Therefore, this experimental study aimed to investigate the cellular targets of hAM protein extracts (hAMPE) in HCC through in vitro studies. Our results showed that hAMPE is able to modify oxidative stress environment in all HCC cell lines, as well as its cell cycle. hAMPE differently targets deoxyribonucleic acid (DNA), P21, P53, β-catenin and multidrug resistance (MDR) proteins in HCC cell lines. In conclusion, hAMPE has several targets in HCC, being clear that the success of this treatment depends of a personalized therapy based on the biological and genetic characteristics of the tumor.

2016-10Journal article

Restricted access

Membrana amniótica: uma opção terapêutica para o cancro?

Publication . Mamede, Ana Catarina Manjolinha; Botelho, Maria Filomena Rabaça Roque; Baptista, Cláudio Jorge Maia

As propriedades anti-cancerígenas da membrana amniótica humana têm sido investigadas ao longo da última década. Estudos in vitro e in vivo revelaram que as células derivadas da membrana amniótica e meio por ela condicionado poderão vir a ser utilizados na terapia do cancro. O carcinoma hepatocelular representa atualmente uma importante causa de morte em todo o mundo. O transplante hepático e a ressecção cirúrgica por hepatectomia parcial são as únicas opções curativas atualmente disponíveis para o carcinoma hepatocelular em estadio inicial. Devido à assintomatologia da doença, o carcinoma hepatocelular é normalmente diagnosticado numa fase avançada não existindo, para tal, terapêuticas curativas adequadas. Neste caso, a quimioterapia e a radioterapia são frequentemente prescritas com o objetivo de aliviar os sintomas associados à normal progressão da doença. Assim sendo, é urgente descobrir novos agentes terapêuticos que se revelem eficazes contra o carcinoma hepatocelular. Até agora, o efeito da membrana amniótica enquanto tecido não foi investigado na doença oncológica. Por este motivo, o objetivo deste trabalho foi avaliar o efeito de extratos das membranas amnióticas humanas (hAMPE, do inglês human amniotic membrane protein extracts) no cancro humano, particularmente no carcinoma hepatocelular, recorrendo para tal a diversos modelos in vitro e in vivo, bem como a inúmeras técnicas de biologia celular e molecular. Os hAMPE foram capazes de inibir a atividade metabólica de diversas linhas celulares de cancro humano, entre as quais o carcinoma hepatocelular. Estudos pormenorizados revelam que os hAMPE são capazes de inibir a atividade metabólica, o conteúdo proteico e o conteúdo de ácido desoxirribonucleico (ADN) nas células de todas as linhas celulares de carcinoma hepatocelular estudadas, de forma dependente da dose e do tempo de exposição. O tratamento foi capaz de induzir a morte celular sendo, no entanto, a via de morte induzida dependente do perfil particular de cada linha celular. Desta forma, a via intrínseca da apoptose foi estimulada nas células da linha celular HuH7, tal como confirmado pelo aumento da expressão da razão BAX/BCl2, do citocromo C, da caspase 9 e da caspase 3. Por outro lado, a via extrínseca da apoptose foi induzida pelos hAMPE nas células HepG2 e Hep3B2.1-7. Nas células destas linhas celulares, foi registado um aumento da expressão da caspase 3 e da caspase 8. Nas células da linha celular HepG2 foi também observada necrose tumoral. Os hAMPE foram capazes de modificar o microambiente tumoral oxidativo de todas as linhas celulares de carcinoma hepatocelular estudadas, bem como o seu ciclo celular. Neste estudo verificou-se que os hAMPE atuaram de forma diferente a nível dos danos no ADN, da P21, da P53, da β-catenina, das proteínas de multirresistência (MDR, do inglês multidrug resistance) e dos transportadores de glicose (GLUT, do inglês glucose transporters) nas linhas celulares de carcinoma hepatocelular. Os hAMPE parecem surtir um efeito potenciador do 5-Fluouracilo (5-FU), da doxorrubicina, da cisplatina e do sorafenib, apesar da resposta obtida não ser homogénea entre as linhas celulares consideradas. Os resultados in vivo confirmaram, mais uma vez, que o sucesso da terapia com os hAMPE depende do perfil de cada linha celular. Os hAMPE apresentaram citotoxicidade seletiva, uma vez que não foram capazes de inibir a atividade metabólica, o conteúdo proteico e o conteúdo de ADN das células de uma linha celular não tumorigénica. Os resultados obtidos contribuíram para o estudo da terapia anti-cancerígena com recursos às membranas fetais, abrindo novas oportunidades no que à terapia do carcinoma hepatocelular diz respeito. Os nossos resultados sugerem também que as características genéticas e biológicas das linhas celulares são responsáveis pela resposta celular à terapia, tornando claro que as terapias anti-cancerígenas devem ser preferencialmente personalizadas.

2017-05Doctoral thesis

Open access