Publications
Recent Publications
2023
Cristina J. Dias, Francesco Papi, Maxime Denis, Cristina Nativi, M. Graça P. M. S. Neves, M. Amparo F. Faustino*
α,α′-Dioxothiones are very reactive species and can participate in cycloaddition reactions with several compounds. Porphyrins bearing vinyl groups are interesting scaffolds for further functionalization namely by cycloaddition reactions; it is well known that porphyrins can react as either a 2π or 4π component in different cycloaddition approaches, such as hetero Diels–Alder reactions. This study reports for the first time the reactivity of a α,α′-dioxothione in the presence of 5,10,15,20-tetraphenylporphyrin bearing a vinyl group (2-VinylTPP) and of its Zn(II) complex (Zn-VinylTPP). The results revealed that the reactivity of α,α′-dioxothione as a heterodienophile or as a heterodiene is dependent on the absence or on the presence of Zn(II) in the porphyrin inner core. Thus, the free base 2-VinylTPP reacted as a diene affording two diastereomeric chlorins (3a and 3b) that are in a tautomeric equilibrium with porphyrin 4, and Zn-VinylTPP reacted as a dienophile affording porphyrin 5 and different oxidized products. All the cycloadducts obtained were revealed to be emissive in the red region and be able to produce 1O2.
New J. Chem. 2023, 47, 20266–20271 https://doi.org/10.1039/D3NJ02859C
Francesco Milanesi, Stefano Roelens, Oscar Francesconi*
Carbohydrates are abundant in Nature, where they are mostly assembled within glycans as free polysaccharides or conjugated to a variety of biological molecules such as proteins and lipids. Glycans exert several functions, including protein folding, stability, solubility, resistance to proteolysis, intracellular traffic, antigenicity, and recognition by carbohydrate-binding proteins. Interestingly, misregulation of their biosynthesis that leads to changes in glycan structures is frequently recognized as a mark of a disease state. Because of glycan ubiquity, carbohydrate binding agents (CBAs) targeting glycans can lead to a deeper understanding of their function and to the development of new diagnostic and prognostic strategies. Synthetic receptors selectively recognizing specific carbohydrates of biological interest have been developed over the past three decades. In addition to the success obtained in the effective recognition of monosaccharides, synthetic receptors recognizing more complex guests have also been developed, including di- and oligosaccharide fragments of glycans, shedding light on the structural and functional requirements necessary for an effective receptor. In this review, the most relevant achievements in molecular recognition of glycans and their fragments will be summarized, highlighting potentials and future perspectives of glycan-targeting synthetic receptors.
ChemPlusChem 2023, e202300598 https://doi.org/10.1002/cplu.202300598
Silvia Fallarini, Linda Cerofolini, Maria Salobehaj, Domenico Rizzo, Giulia Roxana Gheorghita, Giulia Licciardi, Daniela Eloisa Capialbi, Valerio Zullo, Andrea Sodini, Cristina Nativi*, and Marco Fragai*
Targeting immune checkpoints is a well-established strategy in cancer therapy, and antibodies blocking PD-1/PD-L1 interactions to restore the immunological activity against cancer cells have been clinically validated. High-affinity mutants of the PD-1 ectodomain have recently been proposed as an alternative to antibodies to target PD-L1 on cancer cells, shedding new light on this research area. In this dynamic scenario, the PD-1 mutant, here reported, largely expands the chemical space of nonantibody and nonsmall-molecule inhibitor therapeutics that can be used to target cancer cells overexpressing PD-L1 receptors. The polyethylene glycol moieties and the immune response-stimulating carbohydrates, used as site-selective tags, represent the proof of concept for future applications.
Biomacromolecules 2023, 24, 5428–5437 https://doi.org/10.1021/acs.biomac.3c00893
Cristina Di Carluccio, Francesco Milanesi, Monica Civera, Celeste Abreu, Sara Sattin, Oscar Francesconi, Antonio Molinaro, Ondřej Vaněk, Roberta Marchetti,* Alba Silipo
We investigated two recently synthesized and characterized sialyl derivatives, bearing the Neu5Ac-α-(2-6)-Gal epitope, as promising binders for Siglec-7, an inhibitory Siglec mainly found on natural killer cells. A variety of sialoglycan structures can be recognized by Siglec-7 with implications in the modulation of immune responses. Notably, overexpression of sialylated glycans recognized by Siglec-7 can be associated with the progression of several tumors, including melanoma and renal cell carcinoma. NOE-based NMR techniques, including Saturation Transfer Difference and transferred-NOESY NMR, together with molecular docking and dynamic simulations were combined to shed light on the molecular basis of Siglec-7 recognition of two conformationally constrained Sialyl-Tn antigen analogs. We, therefore, identify the ligands epitope mapping and their conformational features and propose 3D models accurately describing the protein-ligand complexes. We found that the binding site of Siglec-7 can accommodate both synthetic analogs, with the sialic acid mainly involved in the interaction. Moreover, the flexibility of Siglec-7 loops allows a preferred accommodation of the more rigid compound bearing a biphenyl moiety at position 9 of the sialic acid that contributed to the interaction to a large extent. Our findings provided insights for developing potential novel high affinity ligands for Siglec-7 to hinder tumor evasion.
Eur.J. Org.Chem. 2023, 26, e2023006 https://doi.org/10.1002/ejoc.202300644
Carlos J. P. Monteiro,* Maria G. P. M. S. Neves, Cristina Nativi, Adelaidec Almeida and Maria Amparo F. Faustino*
Cellulose is the most abundant natural biopolymer and owing to its compatibility with biological tissues, it is considered a versatile starting material for developing new and sustainable materials from renewable resources. With the advent of drug-resistance among pathogenic microorganisms, recent strategies have focused on the development of novel treatment options and alternative antimicrobial therapies, such as antimicrobial photodynamic therapy (aPDT). This approach encompasses the combination of photoactive dyes and harmless visible light, in the presence of dioxygen, to produce reactive oxygen species that can selectively kill microorganisms. Photosensitizers for aPDT can be adsorbed, entrapped, or linked to cellulose-like supports, providing an increase in the surface area, with improved mechanical strength, barrier, and antimicrobial properties, paving the way to new applications, such as wound disinfection, sterilization of medical materials and surfaces in different contexts (industrial, household and hospital), or prevention of microbial contamination in packaged food. This review will report the development of porphyrinic photosensitizers supported on cellulose/cellulose derivative materials to achieve effective photoinactivation. A brief overview of the efficiency of cellulose based photoactive dyes for cancer, using photodynamic therapy (PDT), will be also discussed. Particular attention will be devoted to the synthetic routes behind the preparation of the photosensitizer-cellulose functional materials.
Int. J. Mol. Sci. 2023, 24 , 3475 https://doi.org/10.3390/ijms24043475
Silvia Fallarini, Francesco Papi, Federico Licciardi, Francesca Natali, Grazia Lombardi, Francesca Maestrelli*, and Cristina Nativi*
Fully synthetic tumor-associated carbohydrate antigen (TACA)-based vaccines are a promising strategy to treat cancer. To overcome the intrinsic low immunogenicity of TACAs, the choice of the antigens’ analogues and multivalent presentation have been proved to be successful. Here, we present the preparation, characterization, and in vitro screening of niosomes displaying multiple copies of the mucin antigen TnThr (niosomes-7) or of TnThr mimetic 1 (niosomes-2). Unprecedentedly, structural differences, likely related to the carbohydrate portions, were observed for the two colloidal systems. Both niosomal systems are stable, nontoxic and endowed with promising immunogenic properties.
Bioconjugate Chem. 2023, 34, 181–192 https://doi.org/10.1021/acs.bioconjchem.2c00383
Francesco Milanesi, Luca Unione, Ana Ardá, Cristina Nativi, Jesús Jiménez-Barbero, Stefano Roelens, Oscar Francesconi*
Supramolecular chemistry meets glycans. Taking advantage of a tweezers-shaped structure, a biomimetic receptor selectively recognizes the GlcNAc2 disaccharide core of a complex N-glycan with a remarkable affinity of 170 uM. Because of the simple structure of the receptor and the ubiquity of the highly conserved GlcNAc2 disaccharide core in N-glycans, the receptor can be a versatile supramolecular tool for glycosciences.
Accepted article on Chem. Eur. J. 2023 https://doi.org/10.1002/chem.202203591
Nastassja Burrini, Mario D’Ambrosio, Matteo Gentili, Roberta Giaquinto, Veronica Settimelli, Cristina Luceri, Marzia Cirri,* Oscar Francesconi*
A synthetic mannose receptor bearing an amphiphilic tail was developed to functionalize doxorubicin-based niosomes. Several niosomal formulations and preparation methods were investigated deeply to finally obtain functionalized niosomes suitable for parental administration, which were stable for over six months and able to encapsulate up to 85% of doxorubicin (DOXO). In vitro studies, carried out towards triple-negative cancer cells (MDA-MB231), overexpressing high-mannose-type glycans, showed a cytotoxic activity comparable to that of DOXO but with an appreciable increment in apoptosis given by the CBA. Moreover, niosomal formulation was observed to reduce doxorubicin-induced cytotoxicity towards normal cell lines of rat cardiomyocytes (H9C2).
Pharmaceutics 2023, 15(1), 235; https://doi.org/10.3390/pharmaceutics15010235
2022
Joachim C. Manning, Veronica Baldoneschi, Laura L. Romero-Hernández, Katharina M. Pichler, Gabriel GarcÍa Caballero, Sabine André, Tanja J. Kutzner, Anna-Kristin Ludwig, Valerio Zullo, Barbara Richichi, Reinhard Windhager, Herbert Kaltner, Stefan Toegel, Hans-Joachim Gabius, Paul V. Murphy* and Cristina Nativi
Pairing glycans with tissue lectins controls multiple effector pathways in (patho)physiology. A clinically relevant example is the prodegradative activity of galectins-1 and -3 (Gal-1 and -3) in the progression of osteoarthritis (OA) via matrix metalloproteinases (MMPs), especially MMP-13. The design of heterobifunctional inhibitors that can block galectin binding and MMPs both directly and by preventing their galectin-dependent induction selectively offers a perspective to dissect the roles of lectins and proteolytic enzymes. We describe the synthesis of such a reagent with a bivalent galectin ligand connected to an MMP inhibitor and of two tetravalent glycoclusters with a subtle change in headgroup presentation for further elucidation of influence on ligand binding. Testing was performed on clinical material with mixtures of galectins as occurring in vivo, using sections of fixed tissue. Two-colour fluorescence microscopy monitored binding to the cellular glycome after optimization of experimental parameters. In the presence of the inhibitor, galectin binding to OA specimens was significantly reduced. These results open the perspective to examine the inhibitory capacity of custom-made ditopic compounds on binding of lectins in mixtures using sections of clinical material with known impact of galectins and MMPs on disease progression.
Bioorg. Med. Chem. 2022, 75, 117068; https://doi.org/10.1016/j.bmc.2022.117068
Oscar Francesconi, Francisco Corzana, Georgia-Ioanna Kontogianni, Giorgio Pesciullesi, Gualdani Roberta, Claudiu T. Supuran, Andrea Angeli, Rafaela Maria Kavasi, Maria Chatzinikolaidou and Cristina Nativi *
Osteosarcoma is a heterogeneous tumor intimately linked to its microenvironment, which promotes its growth and spread. It is generally accompanied by cancer-induced bone pain (CIBP), whose main component is neuropathic pain. The TRPA1 ion channel plays a key role in metastasis and is increasingly expressed in bone cancer. Here, a novel TRPA1 inhibitor is described and tested together with two other known TRPA1 antagonists. The novel lipoyl derivative has been successfully assessed for its ability to reduce human osteosarcoma MG-63 cell viability, motility, and gene expression of the CIBP pro-inflammatory cytokines interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α). A putative three-dimensional (3D) model of the inhibitor covalently bound to TRPA1 is also proposed. The in vitro data suggest that the novel inhibitor described here may be highly interesting and stimulating for new strategies to treat osteosarcomas.
ACS Pharmacol. Transl. Sci. 2022, 5, 1119–1127; https://doi.org/10.1021/acsptsci.2c00114
Susi Burgalassi, Marco Fragai, Oscar Francesconi, Linda Cerofolini, Daniela Monti, Gemma Leone, Stefania Lamponi, Giuseppe Greco, Agnese Magnani* and Cristina Nativi*
Hyaluronic acid (HA) is a naturally occurring polysaccharide with many molecular functions, including maintaining the structure and physiology of the tissues, tissue remodeling, and inflammation. HA is found naturally in physiological tear fluid, possesses excellent mucus-layer-adhesive properties, and is successfully employed in the treatment of dry eye syndrome (DES). However, HA has as major drawback: its rapid in vivo degradation by hyaluronidase. We report on a unique material, namely, HA-3, obtained by the functionalization of HA with the metalloproteinase inhibitor 3 (MMPI). This material is characterized by an increased resistance to hyaluronidase degradation, associated with MMP inhibition properties. The ability of HA-3 to prevent dehydration of human corneal epithelial cells in vitro and in vivo may accelerate the development of more efficient DES treatment and broaden the application of HA in human diseases.
ACS Macro Lett. 2022, 11, 1190–1194 ; https://doi.org/10.1021/acsmacrolett.2c00455
Pasquale Palladino, Francesco Papi, Maria Minunni, Cristina Nativi* and Simona Scarano *
Abnormal glycoconjugates have distinctly been recognized as potential biomarkers for cancer diagnosis. A great deal of attention has been focused on Tn antigen, an oversimplified mucin-1 O-glycan, over-expressed in different cancers. Herein, we investigate the possibility to replace the use of anti-Tn monoclonal antibodies with an innovative class of catecholamine-based Molecularly Imprinted Polymers (MIPs), emerging in recent years as promising tools for bioanalytical applications. MIPs are synthetic receptors characterized by high sensitivity and specificity towards the imprinted target. Here, original polynorepinephrine-based MIPs coupled to Surface Plasmon Resonance biosensing for Tn antigen recognition are reported. We have verified the imprinting and binding capacity of these MIPs towards very small antigenic entities, represented by the natural Tn antigen and the TnThr mimetic 1 (conjugated to BSA or linked to a MUC1 hexapeptide analogue), and compared the biosensor performances with an anti-Tn monoclonal antibody. The results clearly display the effectiveness of the pursued imprinting strategies.
ACS Pharmacol. Transl. Sci. 2022, 5, 1119–1127; https://doi.org/10.1002/cplu.202200068
Oscar Francesconi, Lorena Donnici, Marco Fragai, Elisa Pesce, Mauro Bombaci, Alessandra Fasciani, Lara Manganaro, Matteo Conti, Renata Grifantini,* Raffaele De Francesco,* Cristina Nativi,* Stefano Roelens
Developing strategies against the SARS-CoV-2 is currently a main research subject. SARS-CoV-2 infects host cells by binding to human ACE2 receptors. Both, virus and ACE2, are highly glycosylated, and exploiting glycans of the SARS-CoV-2 envelope as binding sites for ACE2 represents a virus strategy for attacking the human host. We report here that a family of mannose-binding synthetic carbohydrate-binding agents (CBAs) inhibits SARS-CoV-2 infection, showing broad neutralizing activity vs. several variants of the spike protein. Preliminary tests indicated that the investigated CBAs interact with the spike protein rather than with ACE2. For a lead compound (IDS060), which has been selected among others for its lack of cytotoxicity, evidence of binding to the RBD of the spike protein has been found by NMR experiments, while competitive binding assays in the presence of IDS060 showed inhibition of binding of RBD to hACE2, although neutralizing activity was also observed with variants showing reduced or depleted binding.
iScience 2022, 25, 104239 ; https://doi.org/10.1016/j.isci.2022.104239
Rosa Ester Forgione, Ferran Fabregat Nieto, Cristina Di Carluccio, Francesco Milanesi, Martina Fruscella, Francesco Papi, Cristina Nativi, Antonio Molinaro, Pasquale Palladino, Simona Scarano, Maria Minunni, Marco Montefiori, Monica Civera, Sara Sattin, Oscar Francesconi, Roberta Marchetti, Alba Silipo*
Here, two conformationally constrained sialyl analogues were synthesized and characterized in their interaction with the inhibitory Siglec, human CD22 (h-CD22). An orthogonal approach, including biophysical assays (SPR and fluorescence), ligand-based NMR techniques, and molecular modelling, was employed to disentangle the interaction mechanisms at a molecular level. The results showed that the Sialyl-TnThr antigen analogue represents a promising scaffold for the design of novel h-CD22 inhibitors. Our findings also suggest that the introduction of a biphenyl moiety at position 9 of the sialic acid hampers canonical accommodation of the ligand in the protein binding pocket, even though the affinity with respect to the natural ligand is increased. Our results address the search for novel modifications of the Neu5Ac-α(2-6)-Gal epitope, outline new insights for the design and synthesis of high-affinity h-CD22 ligands, and offer novel prospects for therapeutic intervention to prevent autoimmune diseases and B-cell malignancies.
ChemBioChem 2022, 23, e202200076; https://doi.org/10.1002/cbic.202200076
Oscar Francesconi,* Andrea Ienco, Francesco Papi, Marta Dolce, Andrea Catastini, Cristina Nativi and Stefano Roelens*
The selective recognition of caffeine in water among structurally related xanthines and purine or pyrimidine bases was achieved by a simple tweezer-shaped receptor featuring sulfonate hydrosolubilizing groups. The remarkable affinity for caffeine, among the highest reported thus far in the literature and larger than that shown by adenosine receptors of all subtypes, stems from a synergistic combination of hydrogen bonding, CH−π, and π-stacking interactions.
J. Org. Chem. 2022, 87, 5, 2662–2667; https://doi.org/10.1021/acs.joc.1c02620
Chiara Demartini,* Rosaria Greco, Giulia Magni, Anna Maria Zanaboni, Benedetta Riboldi, Miriam Francavilla, Cristina Nativi, Stefania Ceruti and Cristina Tassorelli
Preclinical data point to the contribution of transient receptor potential ankyrin 1 (TRPA1) channels to the complex mechanisms underlying migraine pain. TRPA1 channels are expressed in primary sensory neurons, as well as in glial cells, and they can be activated/sensitized by inflammatory mediators. The aim of this study was to investigate the relationship between TRPA1 channels and glial activation in the modulation of trigeminal hyperalgesia in preclinical models of migraine based on acute and chronic nitroglycerin challenges. Rats were treated with ADM_12 (TRPA1 antagonist) and then underwent an orofacial formalin test to assess trigeminal hyperalgesia. mRNA levels of pro- and anti-inflammatory cytokines, calcitonin gene-related peptide (CGRP) and glia cell activation were evaluated in the Medulla oblongata and in the trigeminal ganglia. In the nitroglycerin-treated rats, ADM_12 showed an antihyperalgesic effect in both acute and chronic models, and it counteracted the changes in CGRP and cytokine gene expression. In the acute nitroglycerin model, ADM_12 reduced nitroglycerin-induced increase in microglial and astroglial activation in trigeminal nucleus caudalis area. In the chronic model, we detected a nitroglycerin-induced activation of satellite glial cells in the trigeminal ganglia that was inhibited by ADM_12. These findings show that TRPA1 antagonism reverts experimentally induced hyperalgesia in acute and chronic models of migraine and prevents multiple changes in inflammatory pathways by modulating glial activation.
Int. J. Mol. Sci. 2022, 23(22), 14085; https://doi.org/10.3390/ijms232214085