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2021
Fialho, L, Araújo D, Alves VD, Roma-Rodrigues C, Baptista PV, Fernandes AR, Freitas F, Reis MAM.  2021.  Cation-mediated gelation of the fucose-rich polysaccharide FucoPol: preparation and characterization of hydrogel beads and their cytotoxicity assessment, 2021. International Journal of Polymeric Materials and Polymeric Biomaterials. 70(2):90-99. AbstractWebsite
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Raposo, LR, Silva A, Silva D, Roma-Rodrigues C, Espadinha M, Baptista PV, Santos MMM, Fernandes AR.  2021.  Exploiting the antiproliferative potential of spiropyrazoline oxindoles in a human ovarian cancer cell line, 2021. Bioorganic & Medicinal Chemistry. 30:115880. AbstractWebsite

Cancer is still one of the deadliest diseases worldwide despite the efforts in its early detection and treatment strategies. However, most chemotherapeutic agents still present side effects in normal tissues and acquired resistance that limit their efficacy. Spiropyrazoline oxindoles might be good alternatives as they have shown antiproliferative activity in human breast and colon cancer cell lines, without eliciting cytotoxicity in healthy cells. However, their potential for ovarian cancer was never tested. In this work, the antiproliferative activity of five spiropyrazoline oxindoles was assessed in ovarian cancer cells A2780 and the biological targets and mechanism of action of the most promising compound evaluated. Compound 1a showed the highest antiproliferative effect, as well as the highest selectivity for A2780 cells compared to healthy fibroblasts. This antiproliferative effect results from the induction of cell death by mitochondria-mediated apoptosis and autophagy. In vitro DNA interaction studies demonstrated that 1a interacts with DNA by groove-binding, without triggering genotoxicity. In addition, 1a showed a strong affinity to bovine serum albumin that might be important for further inclusion in drug delivery platforms. Proteomic studies reinforced 1a role in promoting A2780 endoplasmatic reticulum (ER) stress by destabilizing the correct protein folding which triggers cell death via apoptosis and autophagy.

2020
Kordestani, N, Rudbari HA, Fernandes AR, Raposo LR, Baptista PV, Ferreira D, Bruno G, Bella G, Scopelliti R, Braun JD, Herbert DE, Blacque O.  2020.  Antiproliferative Activities of Diimine-Based Mixed Ligand Copper(II) Complexes, 2020. ACS Comb Sci. 22(2):89-99. AbstractWebsite

A series of Cu(diimine)(X-sal)(NO3) complexes, where the diimine is either 2,2'-bipyridine (bpy) or 1,10-phenanthroline (phen) and X-sal is a monoanionic halogenated salicylaldehyde (X = Cl, Br, I, or H), have been synthesized and characterized by elemental analysis and X-ray crystallography. Penta-coordinate geometries copper(II) were observed for all cases. The influence of the diimine coligands and different halogen atoms on the antiproliferative activities toward human cancer cell lines have been investigated. All Cu(II) complexes were able to induce a loss of A2780 ovarian carcinoma cell viability, with phen derivatives more active than bpy derivatives. In contrast, no in vitro antiproliferative effects were observed against the HCT116 colorectal cancer cell line. These cytotoxicity differences were not due to a different intracellular concentration of the complexes determined by inductively coupled plasma atomic emission spectroscopy. A small effect of different halogen substituents on the phenolic ring was observed, with X = Cl being the most highly active toward A2780 cells among the phen derivatives, while X = Br presented the lowest IC50 in A2780 cells for bpy analogs. Importantly, no reduction in normal primary fibroblasts cell viability was observed in the presence of bpy derivatives (IC50 > 40 muM). Mechanistically, complex 1 seems to induce a stronger apoptotic response with a higher increase in mitochondrial membrane depolarization and an increased level of intracellular reactive oxygen species (ROS) compared to complex 3. Together, these data and the low IC50 compared to cisplatin in A2780 ovarian carcinoma cell line demonstrate the potential of these bpy derivatives for further in vivo studies.

Roma-Rodrigues, C, Rivas-Garcia L, Baptista PV, Fernandes AR.  2020.  Gene Therapy in Cancer Treatment: Why Go Nano?, 2020 Pharmaceutics. 12(3) AbstractWebsite

The proposal of gene therapy to tackle cancer development has been instrumental for the development of novel approaches and strategies to fight this disease, but the efficacy of the proposed strategies has still fallen short of delivering the full potential of gene therapy in the clinic. Despite the plethora of gene modulation approaches, e.g., gene silencing, antisense therapy, RNA interference, gene and genome editing, finding a way to efficiently deliver these effectors to the desired cell and tissue has been a challenge. Nanomedicine has put forward several innovative platforms to overcome this obstacle. Most of these platforms rely on the application of nanoscale structures, with particular focus on nanoparticles. Herein, we review the current trends on the use of nanoparticles designed for cancer gene therapy, including inorganic, organic, or biological (e.g., exosomes) variants, in clinical development and their progress towards clinical applications.

Roma-Rodrigues, C, Pombo I, Fernandes AR, Baptista PV.  2020.  Hyperthermia Induced by Gold Nanoparticles and Visible Light Photothermy Combined with Chemotherapy to Tackle Doxorubicin Sensitive and Resistant Colorectal Tumor 3D Spheroids, 2020. Int J Mol Sci. 21(21) AbstractWebsite

Current cancer therapies are frequently ineffective and associated with severe side effects and with acquired cancer drug resistance. The development of effective therapies has been hampered by poor correlations between pre-clinical and clinical outcomes. Cancer cell-derived spheroids are three-dimensional (3D) structures that mimic layers of tumors in terms of oxygen and nutrient and drug resistance gradients. Gold nanoparticles (AuNP) are promising therapeutic agents which permit diminishing the emergence of secondary effects and increase therapeutic efficacy. In this work, 3D spheroids of Doxorubicin (Dox)-sensitive and -resistant colorectal carcinoma cell lines (HCT116 and HCT116-DoxR, respectively) were used to infer the potential of the combination of chemotherapy and Au-nanoparticle photothermy in the visible (green laser of 532 nm) to tackle drug resistance in cancer cells. Cell viability analysis of 3D tumor spheroids suggested that AuNPs induce cell death in the deeper layers of spheroids, further potentiated by laser irradiation. The penetration of Dox and earlier spheroid disaggregation is potentiated in combinatorial therapy with Dox, AuNP functionalized with polyethylene glycol (AuNP@PEG) and irradiation. The time point of Dox administration and irradiation showed to be important for spheroids destabilization. In HCT116-sensitive spheroids, pre-irradiation induced earlier disintegration of the 3D structure, while in HCT116 Dox-resistant spheroids, the loss of spheroid stability occurred almost instantly in post-irradiated spheroids, even with lower Dox concentrations. These results point towards the application of new strategies for cancer therapeutics, reducing side effects and resistance acquisition.

Fernandes, AR, Mendonça-Martins I, Santos MFA, Raposo LR, Mendes R, Marques J, Romão CC, Romão MJ, Santos-Silva T, Baptista PV.  2020.  Improving the Anti-inflammatory Response via Gold Nanoparticle Vectorization of CO-Releasing Molecules, 2020. ACS Biomaterials Science & Engineering. 6(2):1090-1101. AbstractWebsite
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Choroba, K, Raposo LR, Palion-Gazda J, Malicka E, Erfurt K, Machura B, Fernandes AR.  2020.  In vitro antiproliferative effect of vanadium complexes bearing 8-hydroxyquinoline-based ligands - the substituent effect, 2020. Dalton Trans. 49(20):6596-6606. AbstractWebsite

This is the first comprehensive study demonstrating the antiproliferative effect of vanadium complexes bearing 8-hydroxyquinoline (quinH) ligands, including the parent and -CH3 (Me), -NO2, -Cl and -I substituted ligands, on HCT116 and A2780 cancer cell lines. To determine the structure-cytotoxicity relationships seven six-coordinate oxovanadium(v) complexes [VO(OMe)(5,7-(Me)2-quin)2] (1), [VO(OMe)(5,7-Cl2-quin)2] (2), [VO(OMe)(5,7-Cl,I-quin)2] (3), [VO(OMe)(5,7-I2-quin)2] (4), [VO(OMe)(5-NO2-quin)2] (5), [VO(OMe)(5-Cl-quin)2] (6), and [VO(OMe)(quin)2] (7) were investigated. The cytotoxicity of 8-hydroxyquinoline oxovanadium(v) complexes is higher in the A2780 cell line (lower IC50) than that observed for the widely used chemotherapeutic agent, cisplatin, while displaying low cytotoxicity for normal human primary fibroblasts. Substituents introduced into the 8-hydroxyquinoline backbone reduced the antiproliferative effect of the vanadium complexes, and the complexes with the ligand substituted only in the 5 position (5 and 6) were more cytotoxic than those with substituents in the 5,7 positions of the quin backbone (1-4). Depending on the substituent type, the cytotoxicity of 1-4 followed the trend: -Cl > -CH3 > -I. Incubation of A2780 cancer cells with IC50 concentrations of complexes 5, 6 and 7 promoted cellular detachment, possibly through membrane destabilization, and triggered apoptosis and necrosis. ROS production might be responsible for the cell death mechanism observed particularly in the A2780 cells exposed to complexes 5 and 6.

Beola, L, Asin L, Roma-Rodrigues C, Fernandez-Afonso Y, Fratila RM, Serantes D, Ruta S, Chantrell RW, Fernandes AR, Baptista PV, de la Fuente JM, Grazu V, Gutierrez L.  2020.  The Intracellular Number of Magnetic Nanoparticles Modulates the Apoptotic Death Pathway after Magnetic Hyperthermia Treatment, 2020. ACS Appl Mater Interfaces. 12(39):43474-43487. AbstractWebsite

Magnetic hyperthermia is a cancer treatment based on the exposure of magnetic nanoparticles to an alternating magnetic field in order to generate local heat. In this work, 3D cell culture models were prepared to observe the effect that a different number of internalized particles had on the mechanisms of cell death triggered upon the magnetic hyperthermia treatment. Macrophages were selected by their high capacity to uptake nanoparticles. Intracellular nanoparticle concentrations up to 7.5 pg Fe/cell were measured both by elemental analysis and magnetic characterization techniques. Cell viability after the magnetic hyperthermia treatment was decreased to <25% for intracellular iron contents above 1 pg per cell. Theoretical calculations of the intracellular thermal effects that occurred during the alternating magnetic field application indicated a very low increase in the global cell temperature. Different apoptotic routes were triggered depending on the number of internalized particles. At low intracellular magnetic nanoparticle amounts (below 1 pg Fe/cell), the intrinsic route was the main mechanism to induce apoptosis, as observed by the high Bax/Bcl-2 mRNA ratio and low caspase-8 activity. In contrast, at higher concentrations of internalized magnetic nanoparticles (1-7.5 pg Fe/cell), the extrinsic route was observed through the increased activity of caspase-8. Nevertheless, both mechanisms may coexist at intermediate iron concentrations. Knowledge on the different mechanisms of cell death triggered after the magnetic hyperthermia treatment is fundamental to understand the biological events activated by this procedure and their role in its effectiveness.

Restani, RB, Pires RF, Baptista PV, Fernandes AR, Casimiro T, Bonifácio VDB, Aguiar-Ricardo A.  2020.  Nano-in-Micro Sildenafil Dry Powder Formulations for the Treatment of Pulmonary Arterial Hypertension Disorders: The Synergic Effect of POxylated Polyurea Dendrimers, PLGA, and Cholesterol, 2020. 37(6):1900447. AbstractWebsite

Abstract POXylated polyurea dendrimer nanoparticles (PUREG4OOx48) are loaded with sildenafil (SDF) by a supercritical carbon dioxide–assisted (scCO2) impregnation. Further supercritical CO2-assisted spray drying (SASD) leads to hybrid nano-in-micro dry powder formulations that are investigated aiming at efficient pulmonary delivery of SDF in pulmonary arterial hypertension treatment. This is the first report of the production of poly(D,L-lactide-co-glycolide)-cholesterol (PLGA-Chol) microparticles processed by SASD. The optimized formulation of nano-in-microparticles is composed of PLGA, Chol, and PUREG4OOx48, loaded with SDF solutions in a 77:23 ratio (PLGA-Chol:dendrimer, w/w). The dry powders are fully characterized and found to be highly biodegradable and biocompatible, and the SDF release profile evaluates under different pH values. The median mass average diameter (MMAD) of the nano-in-micro systems varies between 2.57 and 5 µm and the fine particle fraction (FPF) between 36% and 29% for PUREG4OMeOx48[PLGA-Chol] and PUREG4OEtOx48[PLGA-Chol], respectively. The data validate the potential use of these new formulations in inhalation therapy. In vitro studies are also carried out in order to evaluate the effect of the free drug in cell viability and formulations cytotoxicity.

Busila, M, Tabacaru A, Mussat V, Vasile BS, Neasu IA, Pinheiro T, Roma-Rodrigues C, Baptista PV, Fernandes AR, Matos AP, Marques F.  2020.  Size-Dependent Biological Activities of Fluorescent Organosilane-Modified Zinc Oxide Nanoparticles, 2020. J Biomed Nanotechnol. 16(2):137-152. AbstractWebsite

Surface modification of zinc oxide nanoparticles (ZnO NPs) is a strategy to tune their biocompatibility. Herein we report on the synthesis of a series of fluorescent ZnO NPs modified with 2-10% (3-glycidyloxypropyl)trimethoxysilane (GPTMS) to investigate the fluorescence properties and to explore their applications in microbiology and biomedicine. The obtained ZnO NPs were characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and Fourier transform infrared spectroscopy (FTIR). Size reduction occurred from ca. 13 nm in unmodified ZnO to 3-4 nm in silane-modified samples and fluorescence spectra showed size-dependent variation of the photoemission bands' intensity. The antibacterial and cytotoxic activities were investigated on Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria, and in ovarian (A2780) and prostate (PC3) cancer cells by tetrazolium/formazan-based methods. The antibacterial effect was higher for E. coli than S. aureus, while the cytotoxic activity was similar for both cancer cells and varied with the particle size. Cell death by apoptosis, and/or necrosis versus autophagy, were explored by flow cytometry using an Annexin V based-method and transmission electron microscopy (TEM). The main mechanism of ZnO NPs toxicity may involve the generation of reactive oxygen species (ROS) and the induction of apoptosis or autophagy. This work revealed the potential utility of GPTMS-modified ZnO NPs in the treatment of bacterial infection and cancer.

Roma-Rodrigues, C, Malta G, Peixoto D, Ferreira LM, Baptista PV, Fernandes AR, Branco PS.  2020.  Synthesis of new hetero-arylidene-9(10H)-anthrone derivatives and their biological evaluation, 2020. Bioorg Chem. 99:103849. AbstractWebsite

New hetero-arylidene-9(10H)-anthrone derivatives (1) were synthesized from reaction of 1,2-dimethyl-3-alkyl imidazolium salts (2) and 9-anthracenecarboxaldehyde. Ion exchange of the anion with dioctyl sulfosuccinate and lithium bis(trifluoromethanesulfonyl)imide led to the preparation of other derivatives. The antiproliferative effect of the compounds was evaluated in human ovarian (A2780) and colorectal (HCT116) carcinoma cell lines and in normal primary human fibroblasts. Compound 1 presented an antiproliferative effect related to the imidazolium pattern of substitution with compounds having a decyl group at the R-position (1c and 3c) showing the highest cytotoxic activities in all cell lines independently of the counter ion. Compounds 1b and 1c internalize A2780 cancer cells via a passive or an active transport, respectively, inducing A2780 cell death via an extrinsic apoptosis (1b) or intrinsic apoptosis and oncosis (1c). The localization of both compounds in the cytoplasm coupled to the absence of reactive oxygen species (ROS) induction suggest that the mechanisms of toxicity might be different than those of other anthracyclines currently used in chemotherapy.

Alves-Barroco, C, Rivas-Garcia L, Fernandes AR, Baptista PV.  2020.  Tackling Multidrug Resistance in Streptococci - From Novel Biotherapeutic Strategies to Nanomedicines, 2020. Front Microbiol. 11:579916. AbstractWebsite

The pyogenic streptococci group includes pathogenic species for humans and other animals and has been associated with enduring morbidity and high mortality. The main reason for the treatment failure of streptococcal infections is the increased resistance to antibiotics. In recent years, infectious diseases caused by pyogenic streptococci resistant to multiple antibiotics have been raising with a significant impact to public health and veterinary industry. The rise of antibiotic-resistant streptococci has been associated to diverse mechanisms, such as efflux pumps and modifications of the antimicrobial target. Among streptococci, antibiotic resistance emerges from previously sensitive populations as result of horizontal gene transfer or chromosomal point mutations due to excessive use of antimicrobials. Streptococci strains are also recognized as biofilm producers. The increased resistance of biofilms to antibiotics among streptococci promote persistent infection, which comprise circa 80% of microbial infections in humans. Therefore, to overcome drug resistance, new strategies, including new antibacterial and antibiofilm agents, have been studied. Interestingly, the use of systems based on nanoparticles have been applied to tackle infection and reduce the emergence of drug resistance. Herein, we present a synopsis of mechanisms associated to drug resistance in (pyogenic) streptococci and discuss some innovative strategies as alternative to conventional antibiotics, such as bacteriocins, bacteriophage, and phage lysins, and metal nanoparticles. We shall provide focused discussion on the advantages and limitations of agents considering application, efficacy and safety in the context of impact to the host and evolution of bacterial resistance.

Das, K, Datta A, Frontera A, Wen YS, Roma-Rodrigues C, Raposo LR, Fernandes AR, Hung CH.  2020.  Zn(II) and Co(II) derivatives anchored with scorpionate precursor: Antiproliferative evaluation in human cancer cell lines, 2020. J Inorg Biochem. 202:110881. AbstractWebsite

A 'scorpionate' type precursor [bdtbpza=bis(3,5-di-t-butylpyrazol-1-yl)acetate] has been employed to synthesize two mononuclear Zn(II) and Co(II) derivatives, namely [Zn(bdtbpza)2 (H2O)2].2.5CH3OH.2[(CH3)3C-C3H2N2-C(CH3)3] (1) and [Co(bdtbpza)2(CH3OH)4] (2) in good yield. Single crystal X-ray diffraction analysis reveals that in 1, the Zn(II) atom is tetrahedrally surrounded by a pair of Oacetate atoms of two bis(pyrazol-1-yl)acetate units and two water molecules; while in 2, the Co(II) atom shows an octahedral environment coordinating a pair of Oacetate atoms of two bis(pyrazol-1-yl)acetate units along with four methanol molecules. The EPR spectra of 2 recorded at 77 and 298K confirmed the tetragonal symmetry of the high spin Co(II). The DFT (Density functional theory) computation is in good agreement with the geometry proposed for compounds 1 and 2. Both the compounds display a high antiproliferative activity against HCT116 (colorectal carcinoma) and A2780 (ovarian carcinoma) cell lines compared to human normal dermal fibroblasts. In the case of A2780 cells, compounds 1 and 2 exhibit IC50 values that are similar to those described for cisplatin, a widely used chemotherapeutic drug. Exposure of A2780 cells to the IC50 concentration of each compound led to an increase of the number of apoptotic and autophagic cells. In the case of compound 1, the accumulation of intracellular ROS (Reactive oxygen species) is responsible for triggering A2780 cell death.

2019
Sutradhar, M, Alegria ECBA, Ferretti F, Raposo LR, Guedes da Silva MFC, Baptista PV, Fernandes AR, Pombeiro AJL.  2019.  Antiproliferative activity of heterometallic sodium and potassium-dioxidovanadium(V) polymers, 2019. J Inorg Biochem. 200:110811. AbstractWebsite

The syntheses of the heterometallic sodium and potassium-dioxidovanadium 2D polymers, [NaVO2(1kappaNOO';2kappaO"-L)(H2O)]n(1) and [KVO2(1kappaNOO';2kappaO';3kappaO"-L)(EtOH)]n(2) (where the kappa notation indicates the coordinating atoms of the polydentate ligand L) derived from (3,5-di-tert-butyl-2-hydroxybenzylidene)-2-hydroxybenzohydrazide (H2L) are reported. The polymers were characterized by IR, NMR, elemental analysis and single crystal X-ray diffraction analysis. The antiproliferative potential of 1 and 2 was examined towards four human cancer cell lines (ovarian carcinoma, A2780, colorectal carcinoma, HCT116, prostate carcinoma, PC3 and breast adenocarcinoma, MCF-7cell lines) and normal human fibroblasts. Complex 1 and 2 showed the highest cytotoxic activity against A2780 cell line (IC50 8.2 and 11.3muM, respectively) with 1>2 and an IC50 in the same range as cisplatin (IC50 3.4muM; obtained in the same experimental conditions) but, interestingly, with no cytotoxicity to healthy human fibroblasts for concentrations up to 75muM. This high cytotoxicity of 1 in ovarian cancer cells and its low cytotoxicity in healthy cells demonstrates its potential for further biological studies. Our results suggest that both complexes induce ovarian carcinoma cell death via apoptosis and autophagy, but autophagy is the main biological cause of the reduction of viability observed and that ROS (reactive oxygen species) may play an important role in triggering cell death.

Alves-Barroco, C, Roma-Rodrigues C, Balasubramanian N, Guimaraes MA, Ferreira-Carvalho BT, Muthukumaran J, Nunes D, Fortunato E, Martins R, Santos-Silva T, Figueiredo AMS, Fernandes AR, Santos-Sanches I.  2019.  Biofilm development and computational screening for new putative inhibitors of a homolog of the regulatory protein BrpA in Streptococcus dysgalactiae subsp. dysgalactiae, 2019. Int J Med Microbiol. 309(3-4):169-181. AbstractWebsite

Streptococcus dysgalactiae subsp. dysgalactiae (SDSD), a Lancefield group C streptococci (GCS), is a frequent cause of bovine mastitis. This highly prevalent disease is the costliest in dairy industry. Adherence and biofilm production are important factors in streptoccocal pathogenesis. We have previously described the adhesion and internalization of SDSD isolates in human cells and now we describe the biofilm production capability of this bacterium. In this work we integrated microbiology, imaging and computational methods to evaluate the biofilm production capability of SDSD isolates; to assess the presence of biofilm regulatory protein BrpA homolog in the biofilm producers; and to predict a structural model of BrpA-like protein and its binding to putative inhibitors. Our results show that SDSD isolates form biofilms on abiotic surface such as glass (hydrophilic) and polystyrene (hydrophobic), with the strongest biofilm formation observed in glass. This ability was mainly associated with a proteinaceous extracellular matrix, confirmed by the dispersion of the biofilms after proteinase K and trypsin treatment. The biofilm formation in SDSD isolates was also confirmed by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Under SEM observation, VSD16 isolate formed cell aggregates during biofilm growth while VSD9 and VSD10 formed smooth and filmy layers. We show that brpA-like gene is present and expressed in SDSD biofilm-producing isolates and its expression levels correlated with the biofilm production capability, being more expressed in the late exponential phase of planktonic growth compared to biofilm growth. Fisetin, a known biofilm inhibitor and a putative BrpA binding molecule, dramatically inhibited biofilm formation by the SDSD isolates but did not affect planktonic growth, at the tested concentrations. Homology modeling was used to predict the 3D structure of BrpA-like protein. Using high throughput virtual screening and molecular docking, we selected five ligand molecules with strong binding affinity to the hydrophobic cleft of the protein, making them potential inhibitor candidates of the SDSD BrpA-like protein. These results warrant further investigations for developing novel strategies for SDSD anti-biofilm therapy.

Choroba, K, Machura B, Kula S, Raposo LR, Fernandes AR, Kruszynski R, Erfurt K, Shul'pina LS, Kozlov YN, Shul'pin GB.  2019.  Copper(ii) complexes with 2,2':6',2''-terpyridine, 2,6-di(thiazol-2-yl)pyridine and 2,6-di(pyrazin-2-yl)pyridine substituted with quinolines. Synthesis, structure, antiproliferative activity, and catalytic activity in the oxidation of alkanes and alcohols, 2019. Dalton Trans. 48(33):12656-12673. AbstractWebsite

A series of 2,2':6',2''-terpyridine (terpy), 2,6-di(thiazol-2-yl)pyridine (dtpy) and 2,6-di(pyrazin-2-yl)pyridine (dppy) derivatives with n-quinolyl substituents (n = 2 and 4) was used to synthesize five-coordinate complexes [CuCl2(n-quinolyl-terpy)] (1-2), [CuCl2(n-quinolyl-dtpy)] (3-4) and [CuCl2(n-quinolyl-dppy)] (5-6), respectively. The main emphasis of the research was to investigate the impact of the triimine skeleton (terpy, dtpy and dppy) and n-quinolyl pendant substituent on the antiproliferative and catalytic properties of 1-6. The obtained Cu(ii) compounds were studied as antiproliferative agents against human colorectal (HCT116) and ovarian (A2780) carcinoma, and they were used as catalysts for the oxidation of alkanes and alcohols with peroxides under mild conditions. The kinetic characteristics of the oxidizing species generated by the catalytic system Cu(ii) complex-H2O2 in CH3CN were obtained from the dependence of the alkane oxidation rate on its initial concentration. A model of competitive interaction of hydroxyl radicals with CH3CN and RH in the catalyst cavity has been proposed which is based on the simultaneous study of kinetics and selectivity in alkane oxidations.

Roma-Rodrigues, C, Fernandes AR, Baptista PV.  2019.  Counteracting the effect of leukemia exosomes by antiangiogenic gold nanoparticles, 2019. Int J Nanomedicine. 14:6843-6854. AbstractWebsite

Purpose: Progression of chronic myeloid leukemia (CML) is frequently associated with increased angiogenesis at the bone marrow mediated by exosomes. The capability of gold nanoparticles (AuNPs) functionalized with antiangiogenic peptides to hinder the formation of new blood vessels has been demonstrated in a chorioallantoic membrane (CAM) model. Methods: Exosomes of K562 CML cell line were isolated and their angiogenic effect assessed in a CAM model. AuNPs functionalized with antiangiogenic peptides were used to block the angiogenic effect of CML-derived exosomes, assessed by evaluation of expression levels of key modulators involved in angiogenic pathways - VEGFA, VEGFR1 (also known as FLT1) and IL8. Results: Exosomes isolated from K562 cells promoted the doubling of newly formed vessels associated with the increase of VEGFR1 expression. This is a concentration and time-dependent effect. The AuNPs functionalized with antiangiogenic peptides were capable to block the angiogenic effect by modulating VEGFR1 associated pathway. Conclusion: Exosomes derived from blast cells are capable to trigger (neo)-angiogenesis, a key factor for the progression and spreading of cancer, in particular in CML. AuNPs functionalized with specific antiangiogenic peptides are capable to block the effect of the exosomes produced by malignant cells via modulation of the intrinsic VEGFR pathway. Together, these data highlight the potential of nanomedicine-based strategies against cancer proliferation.

Jesus, AR, Soromenho MRC, Raposo LR, Esperanca J, Baptista PV, Fernandes AR, Reis PM.  2019.  Enhancement of water solubility of poorly water-soluble drugs by new biocompatible N-acetyl amino acid N-alkyl cholinium-based ionic liquids, 2019. Eur J Pharm Biopharm. 137:227-232. AbstractWebsite

The major challenge of the pharmaceutical industry is to find potential solvents for poorly water-soluble drug molecules. Ionic liquids (ILs) have attracted this industry as (co-) solvents due to their unique physicochemical and biological properties. Herein, a straightforward approach for the enhancement of the water solubility of paracetamol and sodium diclofenac is presented, using new biocompatible N-acetyl amino acid N-alkyl cholinium-based ionic liquids as co-solvents (0.2-1mol%). These new ionic liquids were able to increase the water solubility of these drugs up to four times that in pure water or in an inorganic salt solution. In the presence of these ILs, the drugs lipophilicity (log P was not significantly changed for paracetamol, but for sodium diclofenac it was possible to decrease significantly its lipophilicity. Concerning cytotoxicity in human dermal fibroblasts it was observed that ILs did not show a significant toxicity, and were able to improve cell viability compared with the respective precursors.

Bravo, C, Robalo PM, Marques F, Fernandes AR, Sequeira DA, M. Piedade FM, Garcia HM, de Brito MVJ, Morais TS.  2019.  First heterobimetallic Cu(i)–dppf complexes designed for anticancer applications: synthesis, structural characterization and cytotoxicity, 2019. New Journal of Chemistry. 43(31):12308-12317. AbstractWebsite

A new family of eight heterobimetallic Cu(i)–dppf complexes of general formula [Cu(dppf)L][BF4] with dppf = 1,1′-bis(diphenylphosphino)ferrocene and L representing N,N-, N,O- and N,S-heteroaromatic bidentate ligands have been synthesized and fully characterized by classical analytical, spectroscopic and electrochemical methods. The single crystal structures of [Cu(dppf)(pBI)][BF4] (6), [Cu(dppf)(dpytz)][BF4] (7) and [Cu(dppf)(5-Aphen)][BF4] (8) complexes (where pBI = 2-(2-pyridyl)benzimidazole, dpytz = 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine and 5-Aphen = 1,10-phenanthrolin-5-amine) were determined by X-ray diffraction studies. Cytotoxicity of all complexes was evaluated in two human breast adenocarcinoma cell lines (MCF7 and MDAMB231). All the complexes exhibit high cytotoxicity against both human breast cancer cells with IC50 values far lower than those found for the antitumor drug cisplatin in the same cell lines. The IC50 values on primary healthy fibroblasts are of the same order of magnitude as those found for the tumoral cells.

Oliveira, H, Roma-Rodrigues C, Santos A, Veigas B, Bras N, Faria A, Calhau C, de Freitas V, Baptista PV, Mateus N, Fernandes AR, Fernandes I.  2019.  GLUT1 and GLUT3 involvement in anthocyanin gastric transport- Nanobased targeted approach, 2019. Sci Rep. 9(1):789. AbstractWebsite

Anthocyanins may protect against a myriad of human diseases. However few studies have been conducted to evaluate their bioavailability so their absorption mechanism remains unclear. This study aimed to evaluate the role of two glucose transporters (GLUT1 and GLUT3) in anthocyanins absorption in the human gastric epithelial cells (MKN-28) by using gold nanoparticles to silence these transporters. Anthocyanins were purified from purple fleshed sweet potatoes and grape skin. Silencing of GLUT1 and/or GLUT3 mRNA was performed by adding AuNP@GLUT1 and/or AuNP@GLUT3 to MKN-28 cells. Downregulation of mRNA expression occurred concomitantly with the reduction in protein expression. Malvidin-3-O-glucoside (Mv3glc) transport was reduced in the presence of either AuNP@GLUT1 and AuNP@GLUT3, and when both transporters were blocked simultaneously. Peonidin-3-(6'-hydroxybenzoyl)-sophoroside-5-glucoside (Pn3HBsoph5glc) and Peonidin-3-(6'-hydroxybenzoyl-6''-caffeoyl)-sophoroside-5-glucoside (Pn3HBCsoph5glc) were assayed to verify the effect of the sugar moiety esterification at glucose B in transporter binding. Both pigments were transported with a lower transport efficiency compared to Mv3glc, probably due to steric hindrance of the more complex structures. Interestingly, for Pn3HBCsoph5glc although the only free glucose is at C5 and the inhibitory effect of the nanoparticles was also observed, reinforcing the importance of glucose on the transport regardless of its position or substitution pattern. The results support the involvement of GLUT1 and GLUT3 in the gastric absorption of anthocyanins.

Santos, MM, Raposo LR, Carrera GVSM, Costa A, Dionisio M, Baptista PV, Fernandes AR, Branco LC.  2019.  Ionic Liquids and Salts from Ibuprofen as Promising Innovative Formulations of an Old Drug, 2019. ChemMedChem. 14(9):907-911. AbstractWebsite

Herein we report the synthesis of novel ionic liquids (ILs) and organic salts by combining ibuprofen as anion with ammonium, imidazolium, or pyridinium cations. The methodology consists of an acid-base reaction of neutral ibuprofen with cation hydroxides, which were previously prepared by anion exchange from the corresponding halide salts with Amberlyst A-26(OH). In comparison with the parent drug, these organic salts display higher solubility in water and biological fluids and a smaller degree of polymorphism, which in some cases was completely eliminated. With the exception of [C16 Pyr][Ibu] and [N1,1,2,2OH1 ][Ibu], the prepared salts did not affect the viability of normal human dermal fibroblasts or ovarian carcinoma (A2780) cells. Therefore, these ibuprofen-based ionic liquids may be very promising lead candidates for the development of effective formulations of this drug.

Abdulmawjood, B, Roma-Rodrigues C, Fernandes AR, Baptista PV.  2019.  Liquid biopsies in myeloid malignancies, 2019. Cancer Drug Resistance. 2(4):1044-1061. Abstract

Hematologic malignancies are the most common type of cancer affecting children and young adults, and encompass diseases, such as leukemia, lymphoma, and myeloma, all of which impact blood associated tissues such as the bone marrow, lymphatic system, and blood cells. Clinical diagnostics of these malignancies relies heavily on the use of bone marrow samples, which is painful, debilitating, and not free from risks for leukemia patients. Liquid biopsies are based on minimally invasive assessment of markers in the blood (and other fluids) and have the potential to improve the efficacy of diagnostic/therapeutic strategies in leukemia patients, providing a useful tool for the real time molecular profiling of patients. The most promising noninvasive biomarkers are circulating tumor cells, circulating tumor DNA, microRNAs, and exosomes. Herein, we discuss the role of assessing these circulating biomarkers for the understanding of tumor progression and metastasis, tumor progression dynamics through treatment and for follow-up.

Roma-Rodrigues, C, Pombo I, Raposo L, Pedrosa P, Fernandes AR, Baptista PV.  2019.  Nanotheranostics Targeting the Tumor Microenvironment, 2019. Front Bioeng Biotechnol. 7:197. AbstractWebsite

Cancer is considered the most aggressive malignancy to humans, and definitely the major cause of death worldwide. Despite the different and heterogenous presentation of the disease, there are pivotal cell elements involved in proliferation, differentiation, and immortalization, and ultimately the capability to evade treatment strategies. This is of utmost relevance when we are just beginning to grasp the complexity of the tumor environment and the molecular "evolution" within. The tumor micro-environment (TME) is thought to provide for differentiation niches for clonal development that results in tremendous cancer heterogeneity. To date, conventional cancer therapeutic strategies against cancer are failing to tackle the intricate interplay of actors within the TME. Nanomedicine has been proposing innovative strategies to tackle this TME and the cancer cells that simultaneously provide for biodistribution and/or assessment of action. These nanotheranostics systems are usually multi-functional nanosystems capable to carry and deliver active cargo to the site of interest and provide diagnostics capability, enabling early detection, and destruction of cancer cells in a more selective way. Some of the most promising multifunctional nanosystems are based on gold nanoparticles, whose physic-chemical properties have prompt for the development of multifunctional, responsive nanomedicines suitable for combinatory therapy and theranostics. Herein, we shall focus on the recent developments relying on the properties of gold nanoparticles as the basis for nanotheranostics systems against the heterogeneity within the TME.

Sutradhar, M, Fernandes AR, Paradinha F, Rijo P, Garcia C, Roma-Rodrigues C, Pombeiro AJL, Charmier AJ.  2019.  A new Cu(II)-O-Carvacrotinate complex: Synthesis, characterization and biological activity, 2019. J Inorg Biochem. 190:31-37. AbstractWebsite

Herein, we report the first example of the synthesis of a novel type of Cu(II) complex based on a natural product ligand derived from carvacrol. The copper(II) complex [Cu(DCA)2(EtOH)]2.2EtOH (1, HDCAO-carvacrotinic acid) has been synthesized and characterized by elemental analysis, IR spectroscopy, ESI-MS and single crystal X-ray analysis. Complex 1 and the carvacrotinic acid (2, HDCA) have been studied towards their antimicrobial and antiproliferative activities. For both compounds the antimicrobial activity was assessed against a panel of Gram-positive and Gram-negative bacteria and yeasts. The microdilution method allowed the determination of their Minimum Inhibitory Concentration (MIC) and minimum bactericidal concentration (MBC). Interestingly, both compounds seem to be more effective on yeasts rather than bacteria especially against C. albicans. Regarding the antimicrobial properties, the compounds appear to present a bacteriostatic behaviour, rather than bactericide. The antiproliferative effect of complex 1, O-carvacrotinic acid (HDCA) 2 and carvacrol (CA) 3 used as a reference to compare their antitumoral activity, was examined in 4 human tumor cell lines (ovarian carcinoma (A2780), colorectal carcinoma (HCT116), lung adenocarcinoma (A549) and breast adenocarcinoma (MCF7)) and in normal human primary fibroblasts. Complex 1 exhibits a moderate cytotoxic activity against ovarian carcinoma cells (A2780), with no cytotoxicity in normal primary human fibroblasts. The moderate cytotoxicity observed in A2780 cells was due to an increase of cell apoptosis.

Kourmentza, C, Araujo D, Sevrin C, Roma-Rodriques C, Lia Ferreira J, Freitas F, Dionisio M, Baptista PV, Fernandes AR, Grandfils C, Reis MAM.  2019.  Occurrence of non-toxic bioemulsifiers during polyhydroxyalkanoate production by Pseudomonas strains valorizing crude glycerol by-product, 2019. Bioresour Technol. 281:31-40. AbstractWebsite

While screening for polyhydroxyalkanoate (PHA) producing strains, using glycerol rich by-product as carbon source, it was observed that extracellular polymers were also secreted into the culture broth. The scope of this study was to characterize both intracellular and extracellular polymers, produced by Pseudomonas putida NRRL B-14875 and Pseudomonas chlororaphis DSM 50083, mostly focusing on those novel extracellular polymers. It was found that they fall into the class of bioemulsifiers (BE), as they showed excellent emulsion stability against different hydrocarbons/oils at various pH conditions, temperature and salinity concentrations. Cytotoxicity tests revealed that BE produced by P. chlororaphis inhibited the growth of highly pigmented human melanoma cells (MNT-1) by 50% at concentrations between 150 and 200mug/mL, while no effect was observed on normal skin primary keratinocytes and melanocytes. This is the first study reporting mcl-PHA production by P. putida NRRL B-14785 and bioemulsifier production from both P. putida and P. chlororaphis strains.