The use of fluoroproline in MUC1 antigen enables efficient detection of antibodies in patients with prostate cancer

A structure-based design of a new gene22ration tumor-associated glycopeptides with improved affinity against two anti-MUC1 antibodies is described. These unique antigens feature a fluorinated proline residue, such as a (4S)-4-fluoro-L-proline or 4,4-difluoroproline, at the most immunogenic domain. Binding assays using bio-layer interferometry reveal 3-fold to 10-fold affinity improvement with respect to the natural (glyco)peptides. According to X-ray crystallography and MD simulations, the fluorinated residues stabilize the antigen-antibody complex by enhancing key CH/ interactions. Interestingly, a notable improvement in detection of cancer-associated anti-MUC1 antibodies from serum of patients with prostate cancer is achieved with the non-natural antigens, which proves that these derivatives can be considered better diagnostic tools than the natural antigen for this type of cancer.We thank the Ministerio de Economía y Competitividad (projects CTQ2015-67727-R, UNLR13-4E-1931, CTQ2013-44367-C2-2-P, CTQ2015-64597-C2-1P, and BFU2016-75633-P). I. A. B. thanks the Asociación Española Contra el Cancer en La Rioja for a grant. I. S. A. and G. J. L. B. thank FCT Portugal (PhD studentship and FCT Investigator, respectively) and the EPSRC for funding. G. J. L. B. holds a Royal Society URF and an ERC StG (TagIt). F.C. and G. J. L. B thank the EU (Marie-Sklodowska Curie ITN, Protein Conjugates). R.H-G. thanks Agencia Aragonesa para la Investigación y Desarrollo (ARAID) and the Diputación General de Aragón (DGA, B89) for financial support. The research leading to these results has also received funding from the FP7 (2007-2013) under BioStruct-X (grant agreement N°283570 and BIOSTRUCTX_5186). We thank synchrotron radiation source DIAMOND (Oxford) and beamline I04 (number of experiment mx10121-19). Hokkaido University group acknowledges to JSPS KAKENHI Grant Number 25220206 and JSPS Wakate B KAKENHI Grant Number 24710242. We also thank CESGA (Santiago de Compostela) for computer support

Structure-Based Design of Potent Tumor-Associated Antigens: Modulation of Peptide Presentation by Single-Atom O/S or O/Se Substitutions at the Glycosidic Linkage.

GalNAc-glycopeptides derived from mucin MUC1 are an important class of tumor-associated antigens. α- O-glycosylation forces the peptide to adopt an extended conformation in solution, which is far from the structure observed in complexes with a model anti-MUC1 antibody. Herein, we propose a new strategy for designing potent antigen mimics based on modulating peptide/carbohydrate interactions by means of O → S/Se replacement at the glycosidic linkage. These minimal chemical modifications bring about two key structural changes to the glycopeptide. They increase the carbohydrate-peptide distance and change the orientation and dynamics of the glycosidic linkage. As a result, the peptide acquires a preorganized and optimal structure suited for antibody binding. Accordingly, these new glycopeptides display improved binding toward a representative anti-MUC1 antibody relative to the native antigens. To prove the potential of these glycopeptides as tumor-associated MUC1 antigen mimics, the derivative bearing the S-glycosidic linkage was conjugated to gold nanoparticles and tested as an immunogenic formulation in mice without any adjuvant, which resulted in a significant humoral immune response. Importantly, the mice antisera recognize cancer cells in biopsies of breast cancer patients with high selectivity. This finding demonstrates that the antibodies elicited against the mimetic antigen indeed recognize the naturally occurring antigen in its physiological context. Clinically, the exploitation of tumor-associated antigen mimics may contribute to the development of cancer vaccines and to the improvement of cancer diagnosis based on anti-MUC1 antibodies. The methodology presented here is of general interest for applications because it may be extended to modulate the affinity of biologically relevant glycopeptides toward their receptors

Prognostic Impact of Nutritional Status After Transcatheter Edge-to-Edge Mitral Valve Repair: The MIVNUT Registry

Background Malnutrition is associated with poor prognosis in several cardiovascular diseases. However, its prognostic impact in patients undergoing transcatheter edge-to-edge mitral valve repair (TEER) is not well known. This study sought to assess the prevalence, clinical associations, and prognostic consequences of malnutrition in patients undergoing TEER. Methods and Results A total of 892 patients undergoing TEER from the international MIVNUT (Mitral Valve Repair and Nutritional Status) registry were studied. Malnutrition status was assessed with the Controlling Nutritional Status score. The association of nutritional status with mortality was analyzed with multivariable Cox regression models, whereas the association with heart failure admission was assessed by Fine-Gray models, with death as a competing risk. According to the Controlling Nutritional Status score, 74.4% of patients with TEER had any degree of malnutrition at the time of TEER (75.1% in patients with body mass index <25?kg/m2, 72.1% in those with body mass index ?25?kg/m2). However, only 20% had moderate-severe malnutrition. TEER was successful in most of patients (94.2%). During a median follow-up of 1.6?years (interquartile range, 0.6-3.0), 267 (29.9%) patients died and 256 patients (28.7%) were admitted for heart failure after TEER. Compared with normal nutritional status moderate-severe malnutrition resulted a strong predictor of mortality (adjusted hazard ratio [HR], 2.1 [95% CI, 1.1-2.4]; P<0.001) and heart failure admission (adjusted subdistribution HR, 1.6 [95% CI, 1.1-2.4]; P=0.015). Conclusions Malnutrition is common among patients submitted to TEER, and moderate-severe malnutrition is strongly associated with increased mortality and heart failure readmission. Assessment of nutritional status in these patients may help to improve risk stratification

Synthesis, conformational analysis and: In vivo assays of an anti-cancer vaccine that features an unnatural antigen based on an sp²-iminosugar fragment

Thr/Ser) is a well-known tumor-associated carbohydrate determinant. The use of glycopeptides that incorporate this structure has become a significant and promising niche of research owing to their potential use as anticancer vaccines. Herein, the conformational preferences of a glycopeptide with an unnatural Tn antigen, characterized by a threonine decorated with an sp2-iminosugar-type α-GalNAc mimic, have been studied both in solution, by combining NMR spectroscopy and molecular dynamics simulations, and in the solid state bound to an anti-mucin-1 (MUC1) antibody, by X-ray crystallography. The Tn surrogate can mimic the main conformer sampled by the natural antigen in solution and exhibits high affinity towards anti-MUC1 antibodies. Encouraged by these data, a cancer vaccine candidate based on this unnatural glycopeptide and conjugated to the carrier protein Keyhole Limpet Hemocyanin (KLH) has been prepared and tested in mice. Significantly, the experiments in vivo have proved that this vaccine elicits higher levels of specific anti-MUC1 IgG antibodies than the analog that bears the natural Tn antigen and that the elicited antibodies recognize human breast cancer cells with high selectivity. Altogether, we compile evidence to confirm that the presentation of the antigen, both in solution and in the bound state, plays a critical role in the efficacy of the designed cancer vaccines. Moreover, the outcomes derived from this vaccine prove that there is room for exploring further adjustments at the carbohydrate level that could contribute to designing more efficient cancer vaccines

Deciphering the Non-Equivalence of Serine and Threonine O-glycosylation Points: Implications for Molecular Recognition of the Tn Antigen by an anti-MUC1 Antibody

© 2015 The Authors. The structural features of MUC1-like glycopeptides bearing the Tn antigen (α-O-GalNAc-Ser/Thr) in complex with an anti MUC-1 antibody are reported at atomic resolution. For the α-O-GalNAc-Ser derivative, the glycosidic linkage adopts a high-energy conformation, barely populated in the free state. This unusual structure (also observed in an α-S-GalNAc-Cys mimic) is stabilized by hydrogen bonds between the peptidic fragment and the sugar. The selection of a particular peptide structure by the antibody is thus propagated to the carbohydrate through carbohydrate/peptide contacts, which force a change in the orientation of the sugar moiety. This seems to be unfeasible in the α-O-GalNAc-Thr glycopeptide owing to the more limited flexibility of the side chain imposed by the methyl group. Our data demonstrate the non-equivalence of Ser and Thr O-glycosylation points in molecular recognition processes. These features provide insight into the occurrence in nature of the APDTRP epitope for anti-MUC1 antibodies

Application of a biosorbent to soil: a potential method for controlling water pollution by pesticides

Different strategies are now being optimized to prevent water from agricultural areas being contaminated by pesticides. The aim of this work was to optimize the adsorption of non-polar (tebuconazole, triadimenol) and polar (cymoxanil, pirimicarb) pesticides by soils after applying the biosorbent spent mushroom substrate (SMS) at different rates. The adsorption isotherms of pesticides by three soils and SMS-amended soils were obtained and the adsorption constants were calculated. The distribution coefficients (Kd) increased 1.4023.1 times (tebuconazole), 1.0823.7 times (triadimenol), 1.3142.1 times (cymoxanil), and 0.5523.8 times (pirimicarb) for soils amended with biosorbent at rates between 2 and 75 %. Increasing the SMS rates led to a constant increase in adsorption efficiency for non-polar pesticides but not for polar pesticides, due to the increase in the organic carbon (OC) content of soils as indicated by KOC values. The OC content of SMS-amended soils accounted for more than 90 % of the adsorption variability of non-polar pesticides, but it accounted for only 56.3 % for polar pesticides. The estimated adsorption of SMS-amended soils determined from the individual adsorption of soils and SMS was more consistent with real experimental values for non-polar pesticides than for polar pesticides. The results revealed the use of SMS as a tool to optimize pesticide adsorption by soils in dealing with specific contamination problems involving these compounds. © 2016, Springer-Verlag Berlin Heidelberg