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Projeto de investigação
Biosystems and Integrative Sciences Institute
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Multiplexed cellular profiling identifies an organoselenium compound as an inhibitor of CRM1‐mediated nuclear export
Publication . Jimenez, Lucia; Mayoral‐Varo, Victor; Amenábar, Carlos; Ortega, Judit; Sequeira, João G. N.; Machuqueiro, Miguel; Mourato, Cristiana; Silvestri, Romano; Angeli, Andrea; Carta, Fabrizio; Supuran, Claudiu T.; Megías, Diego; Ferreira, Bibiana; Link, Wolfgang
Chromosomal region maintenance 1 (CRM1 also known as Xpo1 and exportin-1) is the receptor for the nuclear export controlling the intracellular localization and function of many cellular and viral proteins that play a crucial role in viral infections and cancer. The inhibition of CRM1 has emerged as a promising therapeutic approach to interfere with the lifecycle of many viruses, for the treatment of cancer, and to overcome therapy resistance. Recently, selinexor has been approved as the first CRM1 inhibitor for the treatment of multiple myeloma, providing proof of concept for this therapeutic option with a new mode of action. However, selinexor is associated with dose-limiting toxicity and hence, the discovery of alternative small molecule leads that could be developed as less toxic anticancer and antiviral therapeutics will have a significant impact in the clinic. Here, we report a CRM1 inhibitor discovery platform. The development of this platform includes reporter cell lines that monitor CRM1 activity by using red fluorescent protein or green fluorescent protein-labeled HIV-1 Rev protein with a strong heterologous nuclear export signal. Simultaneously, the intracellular localization of other proteins, to be interrogated for their capacity to undergo CRM1-mediated export, can be followed by co-culturing stable cell lines expressing fluorescent fusion proteins. We used this platform to interrogate the mode of nuclear export of several proteins, including PDK1, p110 alpha, STAT5A, FOXO1, 3, 4 and TRIB2, and to screen a compound collection. We show that while p110 alpha partially relies on CRM1-dependent nuclear export, TRIB2 is exported from the nucleus in a CRM1-independent manner. Compound screening revealed the striking activity of an organoselenium compound on the CRM1 nuclear export receptor.
Unveiling molecular details behind improved activity at neutral to alkaline pH of an engineered DyP-type peroxidase
Publication . Borges, Patrícia T.; Silva, Diogo; Silva, Tomás F.D.; Brissos, Vânia; Cañellas, Marina; Lucas, Maria Fátima; Masgrau, Laura; Melo, Eduardo; Machuqueiro, Miguel; Frazão, Carlos; Martins, Lígia O.
DyP-type peroxidases (DyPs) are microbial enzymes that catalyze the oxidation of a wide range of substrates, including synthetic dyes, lignin-derived compounds, and metals, such as Mn2+ and Fe2+, and have enormous biotechnological potential in biorefineries. However, many questions on the molecular basis of enzyme function and stability remain unanswered. In this work, high-resolution structures of PpDyP wild-type and two engineered variants (6E10 and 29E4) generated by directed evolution were obtained. The X-ray crystal structures revealed the typical ferredoxin-like folds, with three heme access pathways, two tunnels, and one cavity, limited by three long loops including catalytic residues. Variant 6E10 displays significantly increased loops' flexibility that favors function over stability: despite the considerably higher catalytic efficiency, this variant shows poorer protein stability compared to wild-type and 29E4 variants. Constant-pH MD simulations revealed a more positively charged microenvironment near the heme pocket of variant 6E10, particularly in the neutral to alkaline pH range. This microenvironment affects enzyme activity by modulating the pK(a) of essential residues in the heme vicinity and should account for variant 6E10 improved activity at pH 7-8 compared to the wild-type and 29E4 that show optimal enzymatic activity close to pH 4. Our findings shed light on the structure-function relationships of DyPs at the molecular level, including their pH-dependent conformational plasticity. These are essential for understanding and engineering the catalytic properties of DyPs for future biotechnological applications. (c) 2022 The Author(s). Published by Elsevier B.V. on behalf of Research Network of Computational and Structural Biotechnology.
Chromenone derivatives as CRM1 inhibitors for targeting glioblastoma
Publication . Princiotto, Salvatore; Jiménez, Lucía; Domínguez, Lucía; Sequeira, João G. N.; Mourato Paulo, Cristiana Isabel; Orea-Soufi, Alba; da Silva Santos, Bruno Filipe; Dallavalle, Sabrina; Machuqueiro, Miguel; Ferreira, Bibiana; Link, Wolfgang
Glioblastoma (GBM) is one of the most aggressive and deadly cancers. Due to the complexity and redundancy within signaling networks in GBM, targeted inhibitors of specific pathways have shown only limited success. The nuclear export receptor chromosome region maintenance 1 (CRM1) has recently emerged as a promising therapeutic target, as its inhibition can simultaneously disrupt multiple key oncogenic drivers. Herein, whether chromenone derivatives, known for detecting thiol-containing molecules, can function as CRM1 inhibitors is explored. Several chromenonebased derivatives are synthesized and it is demonstrated that they inhibit CRM1-driven nuclear export in a structure- and dose-dependent manner. A preliminary structure–activity relationship is established, providing a rationale for selective CRM1 binding based on molecular docking studies. Additionally, it is showed that the active chromenone derivatives effectively inhibit the nuclear export of endogenous nuclear export signal-containing substrates in GBM cells. Several of these compounds exhibit selective cytotoxicity againstGBM cell lines, highlighting their potential as targeted therapies for GBM.
Comparative responses and effects of exposure to metallic and nanoparticle zinc in the mussel Mytilus galloprovincialis
Publication . Roma, Joana; Missionário, Madalena; Madeira, Carolina; Matos, Ana Rita; Vinagre, Catarina; Costa, Pedro M.; Duarte, Bernardo
Zinc (Zn) nanoparticles (NPs) are widely used in various industrial and commercial applications. Their intensive use in sunscreens, for instance, renders priority to understanding their effects on marine life, to which may be added the intensive use of Zn-based paints and anodes to protect submerged structures. We studied the effects of Zn nanoparticles and ions in the mussel Mytilus galloprovincialis exposed to 1, 10 and 100 μg/L of both zinc forms for up to 28 days. Effects were determined by analysing a battery of biomarkers, from oxidative stress (total antioxidant capacity and catalase activity) to acetylcholinesterase (AChE) activity. The results revealed that mussels responded only marginally differently to ionic and Zn nanoparticles, but also that their response was concentration- and time-dependent, suggesting distinct metabolic modes of action. These variations occurred almost exclusively at the highest concentration tested and were more pronounced as the exposure period increased. An integrated biomarker index (IBR) approach was used encompassing also previous findings (lipid peroxidation and metal accumulation in tissue), which further confirmed that these filter-feeding organisms are considerable targets for zinc exposure in the two forms tested and should be included in studies evaluating the overall toxicological impact of various forms of Zn in the marine environment.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
6817 - DCRRNI ID
Número da atribuição
UIDB/04046/2020