Structural and functional features of Klebsiella pneumoniae capsular degradation by the phage depolymerase KP32gp38: implications for vaccination against K. pneumoniae.

The Klebsiellapneumoniae Przondovirus KP32 presents a complex capsular degradation machinery, composed of the two serotype-specific depolymerases KP32gp38 and KP32gp37. In this work, we performed CPS degradation assays combined with mass spectrometry approaches to identify the reaction product of the K21 serotype CPS degradation by KP32gp38. We determined the crystal structure of the KP32gp38 depolymerase in complex with the identified degradation product, a pyruvated pentasaccharide, named K21-pyr5.

A Novel --Carborane-Based Glucosamine Derivative as a Promising Agent for Boron Neutron Capture Therapy.

Boron Neutron Capture Therapy (BNCT) is a promising cancer treatment that combines tumor-selective boron delivery agents with thermal neutrons to kill cancer cells while sparing normal tissue. BNCT requires boron-containing compounds that exhibit high tumor selectivity and achieve therapeutic boron concentrations within tumor cells. This work focuses on the early development of a novel boron cluster carbohydrate derivative based on the glucosamine structure.

Site-Selective Functionalized PD-1 Mutant for a Modular Immunological Activity against Cancer Cells.

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.

Selective inhibition of indoleamine and tryptophan 2,3-dioxygenases: Comparative study on kynurenine pathway in cell lines via LC-MS/MS-based targeted metabolomics.

In the last decade, the kynurenine pathway, which is the primary metabolic route for tryptophan (TRP) catabolism, has sparked great interest in the pharmaceutical sciences due to its role in immune regulation and cancer immunoediting. In this context, the development of cell-based assays might represent a tool to: i) characterize the cell secretome according to cell types; ii) gain more insight into the role of kynurenines in different disease scenarios; iii) screen hIDO1 (human indoleamine 2,3-dioxygenase) inhibitors and evaluate their effect on downstream TRP-catabolizing enzymes. This paper reports a validated Liquid Chromatography with tandem mass spectrometry (LC-MS/MS) method to simultaneously quantify TRP, L-kynurenine (KYN), xanthurenic acid (XA), 3-hydroxykynurenine (3OHKYN), kynurenic acid (KA), 3-hydroxyanthranilic acid (3OHAA), anthranilic acid (AA), 5-hydroxytryptamine (serotonin, 5HT) and tryptamine (TRYP) in Dulbecco's Modified Eagle and Eagle's Minimum Essential Media (DMEM and EMEM, respectively).

Melanoma Cells Inhibit iNKT Cell Functions via PGE2 and IDO1.

Invariant natural killer T (iNKT) cells are a distinct group of immune cells known for their immunoregulatory and cytotoxic activities, which are crucial in immune surveillance against tumors. They have been extensively investigated as a potential target for adoptive cell immunotherapy. Despite the initial promise of iNKT cell-based immunotherapy as a treatment for melanoma patients, its effective utilization has unfortunately yielded inconsistent outcomes.

A Selective ALDH1A3 Inhibitor Impairs Mesothelioma 3-D Multicellular Spheroid Growth and Neutrophil Recruitment.

Aldehyde dehydrogenase 1A3 (ALDH1A3), one of the three members of the aldehyde dehydrogenase 1A subfamily, has been associated with increased progression and drug resistance in various types of solid tumours. Recently, it has been reported that high ALDH1A3 expression is prognostic of poor survival in patients with malignant pleural mesothelioma (MPM), an asbestos-associated chemoresistant cancer. We treated MPM cells, cultured as multicellular spheroids, with NR6, a potent and highly selective ALDH1A3 inhibitor.

Niosomes as Biocompatible Scaffolds for the Multivalent Presentation of Tumor-Associated Antigens (TACAs) to the Immune System.

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 screening of niosomes displaying multiple copies of the mucin antigen TnThr (niosomes-) or of TnThr mimetic (niosomes-).

A Pilot Study on Clinical Scores, Immune Cell Modulation, and Microbiota Composition in Allergic Patients with Rhinitis and Asthma Treated with a Probiotic Preparation.

Background: Specific drugs and/or immunotherapies are widely used to treat allergies, but drug-induced adverse effects recently led to explore new additional strategies. We studied whether a probiotic preparation (iPROB®; Anallergo SpA, Florence, Italy) is effective in allergic patients and the mechanisms underlying clinical outcomes.

Methods: Eligible patients (n = 28), all suffering from allergic rhinitis with/without bronchial asthma, were consecutively recruited at the Allergology Medical Unit (Novara, Italy) and treated with this probiotic.

The [1,2,4]Triazolo[4,3-a]pyridine as a New Player in the Field of IDO1 Catalytic Holo-Inhibitors.

Inhibitors of indoleamine 2,3-dioxygenase 1 (IDO1) are considered a promising strategy in cancer immunotherapy as they are able to boost the immune response and to work in synergy with other immunotherapeutic agents. Despite the fact that no IDO1 inhibitor has been approved so far, recent studies have shed light on the additional roles that IDO1 mediates beyond its catalytic activity, conferring new life to the field. Here we present a novel class of compounds originated from a structure-based virtual screening made on IDO1 active site.

Fucosylated ubiquitin and orthogonally glycosylated mutant A28C: conceptually new ligands for lectin (BambL).

Two orthogonal, metal free click reactions, enabled to glycosylate ubiquitin and its mutant A28C forming two protein scaffolds with high affinity for BambL, a lectin from the human pathogen . A new fucoside analogue, with high affinity with BambL, firstly synthetized and co-crystallized with the protein target, provided the insights for sugar determinants grafting onto ubiquitin. Three ubiquitin-based glycosides were thus assembled.

Discovery of Highly Potent Benzimidazole Derivatives as Indoleamine 2,3-Dioxygenase-1 (IDO1) Inhibitors: From Structure-Based Virtual Screening to Pharmacodynamic Activity.

In this study, a successful medicinal chemistry campaign that exploited virtual, biophysical, and biological investigations led to the identification of a novel class of IDO1 inhibitors based on a benzimidazole substructure. This family of compounds is endowed with an extensive bonding network in the protein active site, including the interaction with pocket C, a region not commonly exploited by previously reported IDO1 inhibitors. The tight packing of selected compounds within the enzyme contributes to the strong binding interaction with IDO1, to the inhibitory potency at the low nanomolar level in several tumoral settings, and to the selectivity toward IDO1 over TDO and CYPs.

Exploring calixarene-based clusters for efficient functional presentation of Streptococcus pneumoniae saccharides.

Calixarenes are promising scaffolds for an efficient clustered exposition of multiple saccharide antigenic units. Herein we report the synthesis and biological evaluation of a calix[6]arene functionalized with six copies of the trisaccharide repeating unit of Streptococcus pneumoniae (SP) serotype 19F. This system has demonstrated its ability to efficiently inhibit the binding between the native 19F capsular polysaccharide and anti-19F antibodies, despite a low number of exposed saccharide antigens, well mimicking the epitope presentations in the polysaccharide.

Selectively Charged and Zwitterionic Analogues of the Smallest Immunogenic Structure of Streptococcus Pneumoniae Type 14.

Zwitterionic polysaccharides (ZPs) have been shown in recent years to display peculiar immunological properties, thus attracting the interest of the carbohydrate research community. To fully elucidate the mechanisms underlying these properties and exploit the potential of this kind of structures, in depth studies are still required. In this context, the preparation of two cationic, an anionic, as well as two zwitterionic tetrasaccharide analogues of the smallest immunogenic structure of type 14 (SP14) capsular polysaccharide are presented.

Synthesis, Docking and Biological Evaluation of a Novel Class of Imidazothiazoles as IDO1 Inhibitors.

IDO1, a key dioxygenase in tryptophan-kynurenine metabolism, appeared in the last 10 years at the vanguard of druggable targets in cancer therapy due to its well-established role both in immune escape and inflammatory neovascularization. Among the pool of IDO1 inhibitors that have entered clinical trials, none have reached approval. The identification of novel inhibitors endowed with better clinical profile, together with the further comprehension of the interactions with residues in IDO1 active site, are still a need.

Synthesis and biological evaluation of a trisaccharide repeating unit derivative of Streptococcus pneumoniae 19A capsular polysaccharide.

Streptococcus pneumoniae (SP) is a common human pathogen associated with a broad spectrum of diseases and it is still a leading cause of mortality and morbidity worldwide, especially in children. Moreover, SP is increasingly associated with drug resistance. Vaccination against the pathogen may thus represent an important strategy to overcome its threats to human health.

Polyphenol Polymerization by an Alternative Oxidative Microbial Enzyme and Characterization of the Biological Activity of Oligomers.

The recombinant catalase-peroxidase HPI from was used as an alternative enzyme in polymerization reactions for the production of (-) epicatechin oligomers and their biological activity was characterized. The enzyme was prepared in two forms: a purified and an immobilized form. Both were tested for their activity in oxidative polymerization reactions, and their stability and reusability were assessed.

A multicomponent approach in the discovery of indoleamine 2,3-dioxygenase 1 inhibitors: Synthesis, biological investigation and docking studies.

Indoleamine 2,3-dioxygenase plays a crucial role in immune tolerance and has emerged as an attractive target for cancer immunotherapy. In this study, the Passerini and Ugi multicomponent reactions have been employed to assemble a small library of imidazothiazoles that target IDO1. While the p-bromophenyl and the imidazothiazole moieties have been kept fixed, a full SAR study has been performed on the side-chain, leading to the discovery of nine compounds with sub-micromolar IC values in the enzyme-based assay.

"In vitro" studies on galectin-3 in human natural killer cells.

Galectin-3 (Gal-3) is a β-galactoside binding protein able to modulate both innate and adaptive immune responses. First identified in macrophages, Gal-3 has been studied widely in many mammalian immune cells, but scarcely in natural killer (NK) cells. The aim of this study was to analyze Gal-3 in human NK cells, isolated from peripheral blood mononuclear cells.

Immunological characterization of a rigid α-Tn mimetic on murine iNKT and human NK cells.

The ability of a rigid α-Tn mimetic (compound 1) to activate murine invariant natural killer T (iNKT) and human natural killer (NK) cells, two subsets of lymphocytes involved in cancer immunesurveillance, was investigated. For this purpose, the mimetic 1 was properly conjugated to a stearic acid containing glycerol-based phospholipid (compound 5) to be presented, in the context of the conserved non polymorphic major histocompatibility complex class I-like molecules (CD1d), to iNKT cells. On the contrary, the mimetic 1 was conjugated to a multivalent peptide-based scaffold (compound 6) to induce NK cell activation.