iBB
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Institute for Bioengineering and Biosciences
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Quantitative FRET Microscopy Reveals a Crucial Role of Cytoskeleton in Promoting PI(4,5)P2 Confinement

Quantitative FRET Microscopy Reveals a Crucial Role of Cytoskeleton in Promoting PI(4,5)P2 Confinement | iBB | Scoop.it

Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) is crucial to many cellular processes in eukaryotes, including membrane trafficking, signal transduction, ion channel function  and cytoskeleton dynamics. This function multiplicity is partially achieved through a dynamic spatiotemporal organization of PI(4,5)P2 within the membrane. In a recent paper published in IJMS, an IBB team (Maria J. Sarmento, Luís Borges-Araújo, Sandra N.Pinto, Nuno Bernardes, Joana Ricardo, Ana Coutinho, Manuel Prieto and Fábio Fernandes) was able to quantify PI(4,5)P2 confinement in living cells making use of FRET imaging measurements. PI(4,5)P2 was found to be significantly compartmentalized at the plasma membrane of HeLa cells. These PI(4,5)P2 enriched domains were shown to not depend on cholesterol content, ruling out an association with lipid rafts. On the other hand, upon inhibition of actin polymerization, compartmentalization of PI(4,5)P2 was almost entirely eliminated, confirming that the cytoskeleton network is the critical component responsible for the formation of nanoscale PI(4,5)P2 domains.

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Gefitinib-Loaded p28-PLGA Nanoparticles Reduce Tumor Burden and Metastases in Lung Cancer

Gefitinib-Loaded p28-PLGA Nanoparticles Reduce Tumor Burden and Metastases in Lung Cancer | iBB | Scoop.it

p28 is a 28 amino acids peptide derived from the bacterial protein azurin. It possesses cell-penetrating capabilities showing preferential enter in cancer cells. Moreover it has been subject in US to two phase I clinical trials as a anticancer agent. In a recent paper published in Journal of Controlled Release, a iBB team (Garizo AR, Dias TP, Fernandes F, Bernardes N, Fialho AM) together with a i3S/UP team (Castro F, Martins C, Almeida A, Barrias CC, Sarmento B) were able for the first time to fabricate p28-functionalized PLGA nanoparticles (NPs) loaded with the EGFR tyrosine kinase inhibitor gefitinib. The results obtained indicate that these NPs interact preferentially with lung cancer cells due to their decoration with p28 peptide. In vitro cytotoxicity assays demonstrate biological activity of the NPs against lung cancer cancer cells. Finally, in vivo studies demonstrated a great potential of the p28-NPs in enhancing the therapeutic effects of gefitinib.

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The Azurin-Derived Peptide CT-p19LC Exhibits Membrane-Active Properties and Induces Cancer Cell Death

The Azurin-Derived Peptide CT-p19LC Exhibits Membrane-Active Properties and Induces Cancer Cell Death | iBB | Scoop.it

The bacterial protein azurin shows an unexpected therapeutic effect against various types of cancer. This property seems to result from its unique structural and surface features. A 28-residue peptide (named p28) derived from the middle part of azurin has been subjected to various studies and reached two clinical trials phase I in US. In a recent paper published in Biomedicines, a iBB team (Ana Rita Garizo, Lígia Coelho, Sandra Pinto, Tiago Dias, Fábio Fernandes, Nuno Bernardes and Arsénio M Fialho) were able to identified another anticancer bioactive peptide (CT-p19LC) derived from the C-terminal of azurin. CT-p19LC proved to interact preferentially with cancer cells, causing a significative inhibition of cell proliferation in a dose dependent manner. Moreover, it is proposed that the mode of action of CT-p19LC involves perturbation or disruption of cancer cell membranes. Overall this study highlights the relevance of azurin as a source of bioactive peptides with potential application in cancer therapies.

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Adaptation to Acetic Acid Stress Involves Structural Alterations and Increased Stiffness of the Yeast Cell Wall

Adaptation to Acetic Acid Stress Involves Structural Alterations and Increased Stiffness of the Yeast Cell Wall | iBB | Scoop.it

The role of the cell wall in yeast response and tolerance to stress is frequently neglected. A BSRG-iBB research paper just published in Scientific Reports, provides, for the first time, a comprehensive view of the alterations occurring at the cell wall in a yeast population adapting to sub-lethal stress induced by acetic acid. The results reveal changes to the cell wall polysaccharide composition and nanomechanical properties, as well as alterations in the transcript levels of key cell wall biosynthetic genes. This paper reinforces the notion that the adaptive yeast response to acetic acid involves coordinated alterations of the cell wall at the biophysical and molecular levels. The gathered knowledge is important for the design of superior industrial strains and for the efficient control of the deleterious activity of spoilage yeasts, particularly in the Food Industry. This research work is first-authored by the PhD student of the PhD programme in Biotechnology and Biosciences Ricardo Ribeiro (FCT_DP AEM fellowship), performed under the supervision of Isabel Sá-Correia. This collaborative study with Fábio Fernandes (BSIRG-iBB) and Mário S. Rodrigues and his team (BioISI, Faculty of Sciences, ULisboa), is also coauthored by Cláudia Godinho (posdoc researcher) and the PhD student Nuno Bourbon-Melo (FCT_DP BIOTECnico) from the BSRG-iBB team.

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