Folding of Class IIa HDAC Derived Peptides into α-helices Upon Binding to Myocyte Enhancer Factor-2 in Complex with DNA

Interaction of transcription factor myocyte enhancer factor-2 (MEF2) family members with class IIa histone deacetylases (HDACs) has been implicated in a wide variety of diseases. Though considerable knowledge on this topic has been accumulated over the years, a high resolution and detailed analysis of the binding mode of multiple class IIa HDAC derived peptides with MEF2D is still lacking. To fulfil this gap, we report here the crystal structure of MEF2D in complex with double strand DNA and four different class IIa HDAC derived peptides, namely HDAC4, HDAC5, HDAC7 and HDAC9. All class IIa HDAC derived peptides form extended amphipathic α-helix structures that fit snugly in the hydrophobic groove of MEF2D domain. Binding mode of class IIa HDAC derived peptides to MEF2D is very similar and occur primarily through nonpolar interactions mediated by highly conserved branched hydrophobic amino acids. Further studies revealed that class IIa HDAC derived peptides are unstructured in solution and appear to adopt a folded α-helix structure only upon binding to MEF2D. Comparison of our peptide-protein complexes with previously characterized structures of MEF2 bound to different co-activators and co-repressors, highlighted both differences and similarities, and revealed the adaptability of MEF2 in protein-protein interactions. The elucidation of the three-dimensional structure of MEF2D in complex with multiple class IIa HDAC derived peptides provide not only a better understanding of the molecular basis of their interactions but also have implications for the development of novel antagonist.

Relevance of amphiphilicity and helicity on the antibacterial action of a histatin 5-derived peptide

Peptide dhvar4, derived from the active domain of our salivary peptide histatin 5, bears a Phe residue in the middle of its hydrophilic face when folded into an α-helix. We then synthesized an analog with this Phe replaced by Lys and two analogs preserving Phe but bearing two and three α-aminoisobutyric acid (Aib) residues to stabilize the helical structure. The aim of this design was to verify which of the two features is more favorable to the biological activity. We performed a conformational study by means of circular dichroism and nuclear magnetic resonance, made antibacterial tests, and assessed the stability of the peptides in human serum. We observed that amphiphilicity is more important than helix stability, provided a peptide can adopt a helical conformation in a membrane-mimetic environment.

Amyposomes, a nanotechnological chaperone with anti-amyloidogenic activity

AIM

The effect of liposomes bi-functionalized with phosphatidic acid and with a synthetic peptide derived from human apolipoprotein E has been evaluated on the aggregation features of different amyloidogenic proteins: human Amyloid β1-40 (Aβ_1-40), transthyretin (TTR) variant S52P, human β2microglobulin (β2m) variants ΔN6 and D76N, Serum Amyloid A (SAA).

METHODS

The formation of fibrillar aggregates of the proteins was investigated by ThioflavinT fluorescence assay and validated by Atomic Force Microscopy.

RESULTS

The results show that liposomes are preventing the transition of non-aggregated forms to the fibrillar state, with stronger effects on Aβ_1-40, β2m ΔN6 and SAA. Liposomes also induce disaggregation of the amyloid aggregates of all the proteins investigated, with stronger effects on Aβ_1-40, β2 D76N and TTR.SPR assays show that liposomes bind Aβ_1-40 and SAA aggregates with high affinity (KD in the nanomolar range) whereas binding to TTR aggregates showed a lower affinity (KD in the micromolar range). Aggregates of β2m variants showed both high and low affinity binding sites. Computed Structural analysis of protein fibrillar aggregates and considerations on the multidentate features of liposomes allow to speculate a common mechanism of action, based on binding the β-stranded peptide regions responsible for the amyloid formation.

CONCLUSION

Thus, multifunctional liposomes perform as pharmacological chaperones with anti-amyloidogenic activity, with a promising potential for the treatment of a number of protein-misfolding diseases.Key messageAmyloidosis is a group of diseases, each due to a specific protein misfolding.Anti-amyloidogenic nanoparticles have been gaining the utmost importance as a potential treatment for protein misfolding disorders.Liposomes bi-functionalized with phosphatidic acid and with a synthetic peptide derived from human apolipoprotein E showed anti-amyloidogenic activity.

Structural and biological characterization of shortened derivatives of the cathelicidin PMAP-36

Cathelicidins, a family of host defence peptides in vertebrates, play an important role in the innate immune response, exhibiting antimicrobial activity against many bacteria, as well as viruses and fungi. This work describes the design and synthesis of shortened analogues of porcine cathelicidin PMAP-36, which contain structural changes to improve the pharmacokinetic properties. In particular, 20-mers based on PMAP-36 (residues 12-31) and 13-mers (residues 12-24) with modification of amino acid residues at critical positions and introduction of lipid moieties of different lengths were studied to identify the physical parameters, including hydrophobicity, charge, and helical structure, required to optimise their antibacterial activity. Extensive conformational analysis, performed by CD and NMR, revealed that the substitution of Pro25-Pro26 with Ala25-Lys26 increased the α-helix content of the 20-mer peptides, resulting in broad-spectrum antibacterial activity against Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Staphylococcus epidermidis strains. Interestingly, shortening to just 13 residues resulted in only a slight decrease in antibacterial activity. Furthermore, two sequences, a 13-mer and a 20-mer, did not show cytotoxicity against HaCat cells up to 64 µM, indicating that both derivatives are not only effective but also selective antimicrobial peptides. In the short peptide, the introduction of the helicogenic α-aminoisobutyric acid forced the helix toward a prevailing 310 structure, allowing the antimicrobial activity to be maintained. Preliminary tests of resistance to Ser protease chymotrypsin indicated that this modification resulted in a peptide with an increased in vivo lifespan. Thus, some of the PMAP-36 derivatives studied in this work show a good balance between chain length, antibacterial activity, and selectivity, so they represent a good starting point for the development of even more effective and proteolysis-resistant active peptides.

Oxime and thiazolidine chemoselective ligation reactions: a green method for cotton functionalization

During the last years, the need to create textile materials provided with peculiar properties has grown significantly. In particular, new textiles are studied to be a first protection in the prevention of living organisms from pathogens. In this regard, modifying a textile material with biologically active compounds, such as antibacterial or antiviral peptides would be useful for many applications. Our work shows a study on the possibility of modifying cotton fabrics with peptides using thiazolidine and oxime chemoselective ligations. For this purpose, an enzymatic oxidation of cellulose in a heterogeneous phase and the possibility to reuse the oxidation solution for multiple times was successfully applied. Model peptides have been designed and synthesized in order to set up the conditions for conjugating peptides to cotton via either thiazolidine or oxime bond. A systematic study of the time, pH, and quantities needed for the best reaction conditions has been conducted. The efficiency and stability of the two chemoselective ligation bonds have been studied and compared.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s10570-023-05253-1.

Isolated α-turns in peptides: a selected literature survey

The results of classifying into various types the 68 examples of isolated α-turns in the X-ray diffraction crystal structures of peptides documented in the literature are presented and discussed in this review article. α-Turns characterized by the trans disposition of all ω torsion angles are common for the backbone linear peptides investigated. In contrast, the cis arrangement of the N-terminal (ω_i + 1 ) torsion angle, among those generated by the three residues internal to the α-turn, is a peculiar feature of 65% of the cyclic peptides. Among linear and cyclic peptides featuring the all-trans disposition of the ω torsion angles, only one third of the α-turns display φ,ψ values not too far from those characterizing regular α-helices. In general, our findings, taken together, suggest that a significant conformational diversity is compatible with the formation of an intramolecularly H-bonded C₁₃ -member pseudocycle (α-turn) in linear and cyclic peptides.

Helical versus Flat Bis-Ferrocenyl End-Capped Peptides: The Influence of the Molecular Skeleton on Redox Properties

Despite the fact that peptide conjugates with a pendant ferrocenyl (Fc) have been widely investigated, bis-ferrocenyl end-capped peptides are rarely synthetized. In this paper, in addition to the full characterization of the Fc-CO-[L-Dap(Boc)]n-NH-Fc series, we report a comparison of the three series of bis-ferrocenyl homopeptides synthesized to date, to gain insights into the influence of α-amino isobutyric (Aib), 2,3-diamino propionic (Dap) and Cα,β-didehydroalanine (ΔAla) amino acids on the peptide secondary structure and on the ferrocene redox properties. The results obtained by 2D NMR analysis and X-ray crystal structures, and further supported by electrochemical data, evidence different behaviors depending on the nature of the amino acid; that is, the formation of 310-helices or fully extended (2.05-helix) structures. In these foldamers, the orientation of the carbonyl groups in the peptide helix yields a macrodipole with the positive pole on the N-terminal amino acid and the negative pole on the C-terminal amino acid, so that oxidation of the Fc moieties takes place more or less easily depending on the orientation of the macrodipole moment as the peptide chain grows. Conversely, the fully extended conformation adopted by ΔAla flat peptides neither generates a macrodipole nor affects Fc oxidation. The utilization as electrochemical and optical (Circular Dichroism) probes of the two terminal Fc groups, bound to the same peptide chain, makes it possible to study the end-to-end effects of the positive charges produced by single and double oxidations, and to evidence the presence "exciton-coupled" CD among the two intramolecularly interacting Fc groups of the L-Dap(Boc) series.

Carbodiimide-Mediated Beckmann Rearrangement of Oxyma-B as a Side Reaction in Peptide Synthesis

The suppression of side reactions is one of the most important objectives in peptide synthesis, where highly reactive compounds are involved. Recently, the violuric acid derivative Oxyma-B was introduced into peptide synthesis protocols as a promising additive to efficiently control the optical purity of the amino acids prone to racemization. However, we discovered a side reaction involving the Beckmann rearrangement of Oxyma-B during the coupling reaction, which compromises the yield and purity of the target peptides. Here, we present the investigation of the mechanism of this rearrangement and the optimization of the coupling reaction conditions to control it. These results can be taken into account for the design of novel efficient oxime-based coupling reagents.

Is Cys(MTSL) the Best α-Amino Acid Residue to Electron Spin Labeling of Synthetically Accessible Peptide Molecules with Nitroxides?

Electron paramagnetic resonance spectroscopy, particularly its pulse technique double electron-electron resonance (DEER) (also termed PELDOR), is rapidly becoming an extremely useful tool for the experimental determination of side chain-to-side chain distances between free radicals in molecules fundamental for life, such as polypeptides. Among appropriate probes, the most popular are undoubtedly nitroxide electron spin labels. In this context, suitable biosynthetically derived, helical regions of proteins, along with synthetic peptides with amphiphilic properties and antibacterial activities, are the most extensively investigated compounds. A strict requirement for a precise distance measurement has been identified in a minimal dynamic flexibility of the two nitroxide-bearing α-amino acid side chains. To this end, in this study, we have experimentally compared in detail the side-chain mobility properties of the two currently most widely utilized residues, namely, Cys(MTSL) and 2,2,6,6-tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid (TOAC). In particular, two double-labeled, chemically synthesized 20-mer peptide molecules have been adopted as appropriate templates for our investigation on the determination of the model intramolecular separations. These double-Cys(MTSL) and double-TOAC compounds are both analogues of the almost completely rigid backbone peptide ruler which we have envisaged and 3D structurally analyzed as our original, unlabeled compound. Here, we have clearly found that the TOAC side-chain labels are largely more 3D structurally restricted than the MTSL labels. From this result, we conclude that the TOAC residue offers more precise information than the Cys(MTSL) residue on the side chain-to-side chain distance distribution in synthetically accessible peptide molecules.

Management of Hypothyroidism in Internal Medicine: Patient Profile and Effects of an Educational Programme in the Cluster-Randomized FADOI TIAMO Study

BACKGROUND AND AIMS

There is still limited knowledge regarding the clinical profile and appropriateness of treatment in patients with hypothyroidism hospitalized in Internal Medicine (IM) Departments in Italy. The aim of this study is to evaluate: 1) the characteristics of patients and possible deviations from national and international clinical practice recommendations (CPRs) in evidence-based guidelines (EBGs); 2) the improvement of patient management by means of a standardized educational programme (EP).

METHODS

A nationwide multicentre study, comprising two replications of a retrospective survey (phases 1 and 3) with an intervening EP (phase 2) in half of the centres and no EP in the other half, was conducted. The EP was based on outreach visits. Centres were assigned to the two arms of the study, labelled the training group (TG) and control group (CG) respectively, by cluster randomization. Four EBGs and 39 CPRs provided the basis on which 22 treatment management indicators were identified (7 referring to the time of hospital admission, 15 to post-admission).

RESULTS

The 21 participating centres recruited 587 hospitalized patients with hypothyroidism, 421 of which were females (71.7%, mean age 74.1 + 14.4 yrs): 318 in phase 1 and 269 in phase 3. The cause of hypothyroidism was unknown in 282 patients (48%). Evaluation at the time of admission identified satisfactory adherence to CPRs (>50%) for 63.6% of the indicators. In the phase 3, TG centres showed significant improvement vs CG in 4 of the 15 post-admission indicators, while 1 out of 15 was significantly worse.

CONCLUSIONS

The EP based on outreach visits significantly improved some indicators in the management of patients with hypothyroidism, with specific reference to appropriateness of TSH dosage and levothyroxine (LT4) treatment modality.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, identifier NCT05314790.

Targeting Oncogenic Src Homology 2 Domain-Containing Phosphatase 2 (SHP2) by Inhibiting Its Protein-Protein Interactions

We developed a new class of inhibitors of protein-protein interactions of the SHP2 phosphatase, which is pivotal in cell signaling and represents a central target in the therapy of cancer and rare diseases. Currently available SHP2 inhibitors target the catalytic site or an allosteric pocket but lack specificity or are ineffective for disease-associated SHP2 mutants. Considering that pathogenic lesions cause signaling hyperactivation due to increased levels of SHP2 association with cognate proteins, we developed peptide-based molecules with nanomolar affinity for the N-terminal Src homology domain of SHP2, good selectivity, stability to degradation, and an affinity for pathogenic variants of SHP2 that is 2-20 times higher than for the wild-type protein. The best peptide reverted the effects of a pathogenic variant (D61G) in zebrafish embryos. Our results provide a novel route for SHP2-targeted therapies and a tool for investigating the role of protein-protein interactions in the function of SHP2.

Cα-Methyl-l-valine: A Preferential Choice over α-Aminoisobutyric Acid for Designing Right-Handed α-Helical Scaffolds

In synthetic peptides containing Gly and coded α-amino acids, one of the most common practices to enhance their helical extent is to incorporate a large number of l-Ala residues along with noncoded, strongly foldameric α-aminoisobutyric acid (Aib) units. Earlier studies have established that Aib-based peptides, with propensity for both the 3₁₀- and α-helices, have a tendency to form ordered three-dimensional structure that is much stronger than that exhibited by their l-Ala rich counterparts. However, the achiral nature of Aib induces an inherent, equal preference for the right- and left-handed helical conformations as found in Aib homopeptide stretches. This property poses challenges in the analysis of a model peptide helical conformation based on chirospectroscopic techniques like electronic circular dichroism (ECD), a very important tool for assigning secondary structures. To overcome such ambiguity, we have synthesized and investigated a thermally stable 14-mer peptide in which each of the Aib residues of our previously designed and reported analogue ABGY (where B stands for Aib) is replaced by C^α-methyl-l-valine (L-AMV). Analysis of the results described here from complementary ECD and ¹H nuclear magnetic resonance spectroscopic techniques in a variety of environments firmly establishes that the L-AMV-containing peptide exhibits a significantly stronger preference compared to that of its Aib parent in terms of conferring α-helical character. Furthermore, being a chiral α-amino acid, L-AMV shows an intrinsic, extremely strong bias for a quite specific (right-handed) screw sense. These findings emphasize the relevance of L-AMV as a more appropriate unit for the design of right-handed α-helical peptide models that may be utilized as conformationally constrained scaffolds.

Conformationally Constrained Peptides with High Affinity to the Vascular Endothelial Growth Factor

The design of efficient vascular endothelial growth factor (VEGF) inhibitors is a high-priority research area aimed at the treatment of pathological angiogenesis. Among other compounds, v114* has been identified as a potent VEGF-binding peptide. In order to improve the affinity to VEGF, we built a conformational constrain in its structure. To this aim, C^α-tetrasubstituted amino acid Aib was introduced into the N-terminal tail, peptide loop, or C-terminal helix. NMR studies confirmed the stabilization of the helical conformation in proximity to the Aib residue. We found that the induction of the N-terminal helical structure or stabilization of the C-terminal helix can noticeably increase the peptide affinity to the VEGF. These peptides efficiently inhibited VEGF-stimulated cell proliferation as well. The insertion of the non-proteinogenic Aib residue significantly enhanced the stability of the peptides in the vitreous environment. Thus, these Aib-containing peptides are promising candidates for the design of VEGF inhibitors with improved properties.

Flat, Cα,β -Didehydroalanine Foldamers with Ferrocene Pendants: Assessing the Role of α-Peptide Dipolar Moments

The foldamer field is continuously expanding as it allows to produce molecules endowed with 3D-structures and functions never observed in nature. We synthesized flat foldamers based on the natural, but non-coded, Cα,β -didehydroalanine α-amino acid, and covalently linked to them two ferrocene (Fc) moieties, as redox probes. These conjugates retain the flat and extended conformation of the 2.05 -helix, both in solution and in the crystal state (X-ray diffraction). Cyclic voltammetry measurements agree with the adoption of the 2.05 -helix, characterized by a negligible dipole moment. Thus, elongated α-peptide stretches of this type are insulators rather than charge conductors, the latter being constituted by peptide α-helices. Also, our homo-tetrapeptide has a N-to-C length of about 18.2 Å, almost double than that (9.7 Å) of an α-helical α-tetrapeptide.

A pH-Induced Reversible Conformational Switch Able to Control the Photocurrent Efficiency in a Peptide Supramolecular System

External stimuli are potent tools that Nature uses to control protein function and activity. For instance, during viral entry and exit, pH variations are known to trigger large protein conformational changes. In Nature, also the electron transfer (ET) properties of ET proteins are influenced by pH-induced conformational changes. In this work, a pH-controlled, reversible 3₁₀ -helix to α-helix conversion (from acidic to highly basic pH values and vice versa) of a peptide supramolecular system built on a gold surface is described. The effect of pH on the ability of the peptide SAM to generate a photocurrent was investigated, with particular focus on the effect of the pH-induced conformational change on photocurrent efficiency. The films were characterized by electrochemical and spectroscopic techniques, and were found to be very stable over time, also in contact with a solution. They were also able to generate current under illumination, with an efficiency that is the highest recorded so far with biomolecular systems.

Probing the E/K Peptide Coiled-Coil Assembly by Double Electron-Electron Resonance and Circular Dichroism

Double electron-electron resonance (DEER, also known as PELDOR) and circular dichroism (CD) spectroscopies were explored for the purpose of studying the specificity of the conformation of peptides induced by their assembly into a self-recognizing system. The E and K peptides are known to form a coiled-coil heterodimer. Two paramagnetic TOAC α-amino acid residues were incorporated into each of the peptides (denoted as K** and E**), and a three-dimensional structural investigation in the presence or absence of their unlabeled counterparts E and K was performed. The TOAC spin-labels, replacing two Ala residues in each compound, are covalently and quasi-rigidly connected to the peptide backbone. They are known not to disturb the native structure, so that any conformational change can easily be monitored and assigned. DEER spectroscopy enables the measurement of the intramolecular electron spin-spin distance distribution between the two TOAC labels, within a length range of 1.5-8 nm. This method allows the individual conformational changes for the K**, K**/E, E**, and E**/K molecules to be investigated in glassy frozen solutions. Our data reveal that the conformations of the E** and K** peptides are strongly influenced by the presence of their counterparts. The results are discussed with those from CD spectroscopy and with reference to the already reported nuclear magnetic resonance data. We conclude that the combined DEER/TOAC approach allows us to obtain accurate and reliable information about the conformation of the peptides before and after their assembly into coiled-coil heterodimers. Applications of this induced fit method to other two-component, but more complex, systems, like a receptor and antagonists, a receptor and a hormone, and an enzyme and a ligand, are discussed.

Sustainable, Site-Specific Linkage of Antimicrobial Peptides to Cotton Textiles

A new general method to covalently link a peptide to cotton via thiazolidine ring formation is developed. Three different analogues of an ultrashort antibacterial peptide are synthesized to create an antibacterial fabric. The chemical ligation approach to the heterogeneous phase made up of insoluble cellulose fibers and a peptide solution in water is adapted. The selective click reaction occurs between an N-terminal cysteine on the peptide and an aldehyde on the cotton matrix. The aldehyde is generated on the primary alcohol of glucose by means of the enzyme laccase and the cocatalyst 2,2,6,6-tetramethylpiperidine-1-oxyl. This keeps the pyranose rings intact and may bring a benefit to the mechanical properties of the fabric. The presence of the peptide on cotton is demonstrated through instant colorimetric tests, UV spectroscopy, IR spectroscopy, and X-ray photoelectron spectroscopy analysis. The antibacterial activity of the peptides is maintained even after their covalent attachment to cotton fibers.

Controlling the Formation of Peptide Films: Fully Developed Helical Peptides are Required to Obtain a Homogenous Coating over a Large Area

The influence of conformational dynamics on the self-assembly process of a conformationally constrained analogue of the natural antimicrobial peptide Trichogin GA IV was analysed by spectroscopic methods, microscopy imaging at nanometre resolution, and molecular dynamics simulations. The formation of peptide films at the air/water interface and their deposition on a graphite or a mica substrate were investigated. A combination of experimental evidence with molecular dynamics simulation was used to demonstrate that only the fully developed helical structure of the analogue promotes formation of ordered aggregates that nucleate the growth of micrometric rods, which give rise to homogenous coating over wide regions of the hydrophilic mica. This work proves the influence of helix flexibility on peptide self-organization and orientation on surfaces, key steps in the design of bioinspired organic/inorganic hybrid materials.

The Secondary Structure of a Major Wine Protein is Modified upon Interaction with Polyphenols

Polyphenols are an important constituent of wines and they are largely studied due to their antioxidant properties and for their effects on wine quality and stability, which is also related to their capacity to bind to proteins. The effects of some selected polyphenols, including procyanidins B1 and B2, tannic acid, quercetin, and rutin, as well as those of a total white wine procyanidin extract on the conformational properties of the major wine protein VVTL1 (Vitis vinifera Thaumatin-Like-1) were investigated by Synchrotron Radiation Circular Dichroism (SRCD). Results showed that VVTL1 interacts with polyphenols as demonstrated by the changes in the secondary (far-UV) and tertiary (near-UV) structures, which were differently affected by different polyphenols. Additionally, polyphenols modified the two melting temperatures (TM) that were found for VVTL1 (32.2 °C and 53.9 °C for the protein alone). The circular dichroism (CD) spectra in the near-UV region revealed an involvement of the aromatic side-chains of the protein in the interaction with phenolics. The data demonstrate the existence of an interaction between polyphenols and VVTL1, which results in modification of its thermal and UV denaturation pattern. This information can be useful in understanding the behavior of wine proteins in presence of polyphenols, thus giving new insights on the phenomena that are involved in wine stability.

Au(iii)-Proline derivatives exhibiting selective antiproliferative activity against HepG2/SB3 apoptosis-resistant cancer cells

This paper deals with the combination of a proline-based moiety with biologically active gold centers in the oxidation states +1 and +3. In particular, six Au(i)/(iii)-proline dithiocarbamato (DTC) complexes with general formulae [Au(DTC)₂] and [Au^IIIX₂(DTC)] (X = Cl, Br) are reported here. After the synthesis of the ligand and the complexes, all derivatives were characterized via several techniques and tested for their stability in DMSO/water media. This study was focused on the demonstration of a peculiar behavior of Au(iii)-DTC species in solution. Finally, the complexes were screened for their antiproliferative activity against 2 human cancer cell lines, namely HepG2 and HepG2/SB3, taken as models of hepatocellular carcinoma. The latter, chosen for its aggressiveness due to the upregulation of the anti-apoptotic protein SerpinB3, was selectively inhibited in terms of growth by some Au(iii)-DTC complexes.

CuII and AuIII Complexes with Glycoconjugated Dithiocarbamato Ligands for Potential Applications in Targeted Chemotherapy

This work is focused on the synthesis, characterization, and preliminary biological evaluation of bio-conjugated Au^III and Cu^II complexes with the aim of overcoming the well-known side effects of chemotherapy by improving the selective accumulation of an anticancer metal payload in malignant cells. For this purpose, carbohydrates were chosen as targeting agents, exploiting the Warburg effect that accounts for the overexpression of glucose-transporter proteins (in particular GLUTs) in the phospholipid bilayer of most neoplastic cells. We linked the dithiocarbamato moiety to the C1 position of three different monosaccharides: d-glucose, d-galactose, and d-mannose. Altogether, six complexes with a 1:2 metal-to-ligand stoichiometry were synthesized and in vitro tested as anticancer agents. One of them showed high cytotoxic activity toward the HCT116 colorectal human carcinoma cell line, paving the way to future in vivo studies aimed at evaluating the role of carbohydrates in the selective delivery of whole molecules into cancerous cells.

Modeling interaction between gp120 HIV protein and CCR5 receptor

The study of the process of HIV entry into the host cell and the creation of biomimetic nanosystems that are able to selectively bind viral particles and proteins is a high priority research area for the development of novel diagnostic tools and treatment of HIV infection. Recently, we described multilayer nanoparticles (nanotraps) with heparin surface and cationic peptides comprising the N-terminal tail (Nt) and the second extracellular loop (ECL2) of CCR5 receptor, which could bind with high affinity some inflammatory chemokines, in particular, Rantes. Because of the similarity of the binding determinants in CCR5 structure, both for chemokines and gp120 HIV protein, here we expand this approach to the study of the interactions of these biomimetic nanosystems and their components with the peptide representing the V3 loop of the activated form of gp120. According to surface plasmon resonance results, a conformational rearrangement is involved in the process of V3 and CCR5 fragments binding. As in the case of Rantes, ECL2 peptide showed much higher affinity to V3 peptide than Nt (K_D  = 3.72 × 10^-8 and 1.10 × 10^-6  M, respectively). Heparin-covered nanoparticles bearing CCR5 peptides effectively bound V3 as well. The presence of both heparin and the peptides in the structure of the nanotraps was shown to be crucial for the interaction with the V3 loop. Thus, short cationic peptides ECL2 and Nt proved to be excellent candidates for the design of CCR5 receptor mimetics.

A novel peptide conformation: the γ-bend ribbon

Unlike the extensively investigated relationship between the peptide β-bend ribbon and its prototypical 310-helix conformation, the corresponding relationship between the narrower γ-bend ribbon and its regular γ-helix counterpart still remains to be studied, as the latter 3D-structures have not yet been experimentally authenticated. In this paper, we describe the results of the first characterization, both in the crystal state and in solution, of the γ-bend ribbon conformation using X-ray diffraction and FT-IR absorption, electronic CD and 2D-NMR spectroscopies applied to an appropriate set of synthetic, homo-chiral, sequential dipeptide oligomers based on (S)-Ala and the known γ-bend inducer, Cα-tetrasubstituted, N-alkylated α-amino acid residue (S)-Cα-methyl-azetidine-carboxylic acid.

Anticancer Gold(III) Peptidomimetics: From Synthesis to in vitro and ex vivo Biological Evaluations

Five new Au^III -peptidodithiocarbamato complexes of the type [Au^III Br₂ (dtc-AA₁ -AA₂ -OR] (in which AA₁ =N-methylglycine (Sar), l/d-Pro; AA₂ =l/d-Ala, α-aminoisobutyric acid (Aib); R=OtBu, triethylene glycol methyl ether), differing with regard to the amino acid sequence and/or the chiral amino acid configuration, were designed to enhance tumor selectivity and bioavailability. The gold(III)-based moiety was functionalized to exploit the targeting properties of the peptidomimetic ligand toward two peptide transporters (namely PEPT1 and PEPT2), which are upregulated in several tumor cells. The compounds were synthesized and fully characterized, mainly by means of elemental analysis, one- and two-dimensional NMR spectroscopy, FT-IR, and UV/Vis spectrophotometry. The crystal structures of three compounds were also solved by X-ray diffraction. In vitro cytotoxicity studies using a panel of human tumor cell lines (A549 [non-small-cell lung carcinoma], MCF-7 [breast cancer], A2780 [ovarian carcinoma], H1975 [non-small-cell lung carcinoma], H460 [large-cell lung carcinoma], and A431 [human epidermoid carcinoma]) showed the dtc-Pro-Aib-OtBu derivative to be very effective, with GI₅₀ values much lower than those of cisplatin. This complex was thus selected for evaluating stability under physiological conditions and possible interactions with serum albumin, as well in PARP-1 enzyme inhibition assays and preliminary ex vivo toxicity experiments on healthy rat tissues.

Chaperone-like effect of ceftriaxone on HEWL aggregation: A spectroscopic and computational study

BACKGROUND

Lysozyme is a widely distributed enzyme present in a variety of tissue and body fluids. Human and hen egg white lysozyme are used as validated model to study protein folding and stability and to understand protein misfolding and aggregation. We recently found that ceftriaxone, a β-lactam antibiotic able to overcome the blood-brain barrier, successfully eliminated the cellular toxic effects of misfolded proteins as Glial Fibrillary Acidic Protein (GFAP) and α-synuclein. To further understand the anti-amyloidogenic properties of ceftriaxone, we studied its activity towards lysozyme aggregation with the aim to investigate a possible chaperone-like activity of this molecule.

METHODS

Here we present the results obtained from fluorescence and synchrotron radiation circular dichroism spectroscopies and from molecular docking and molecular dynamics about the lysozyme-ceftriaxone interaction at neutral and acidic pH values.

RESULTS

We found that ceftriaxone exhibits comparable affinity constants to lysozyme in both experimental pH conditions and that its addition enhanced lysozyme stability reducing its aggregation propensity in acidic conditions. Computational methods allowed the identification of the putative binding site of ceftriaxone, thus rationalizing the spectroscopic results.

CONCLUSIONS

Spectroscopy data and molecular dynamics indicated a protective effect of ceftriaxone on pathological aggregation phenomena suggesting a chaperone-like effect of this molecule on protein folding. General significance These results, in addition to our previous studies on α-synuclein and GFAP, confirm the property of ceftriaxone to inhibit the pathological protein aggregation of lysozyme also by a chaperone-like mechanism, extending the potential therapeutic application of this molecule to some forms of human hereditary systemic amyloidosis.

Amphiphilic polypeptides with prolonged enzymatic stability for the preparation of self-assembled nanobiomaterials

Aib residue distribution in Lys/Aib polymers influences the morphology of forming nanoparticles and the rate of their enzymatic degradation.

Conformational properties, membrane interaction, and antibacterial activity of the peptaibiotic chalciporin A: Multitechnique spectroscopic and biophysical investigations on the natural compound and labeled analogs

In this work, an extensive set of spectroscopic and biophysical techniques (including FT-IR absorption, CD, 2D-NMR, fluorescence, and CW/PELDOR EPR) was used to study the conformational preferences, membrane interaction, and bioactivity properties of the naturally occurring synthetic 14-mer peptaibiotic chalciporin A, characterized by a relatively low (≈20%), uncommon proportion of the strongly helicogenic Aib residue. In addition to the unlabeled peptide, we gained in-depth information from the study of two labeled analogs, characterized by one or two residues of the helicogenic, nitroxyl radical-containing TOAC. All three compounds were prepared using the SPPS methodology, which was carefully modified in the course of the syntheses of TOAC-labeled analogs in view of the poorly reactive α-amino function of this very bulky residue and the specific requirements of its free-radical side chain. Despite its potentially high flexibility, our results point to a predominant, partly amphiphilic, α-helical conformation for this peptaibiotic. Therefore, not surprisingly, we found an effective membrane affinity and a remarkable penetration propensity. However, chalciporin A exhibits a selectivity in its antibacterial activity not in agreement with that typical of the other members of this peptide class.

MANAGEMENT OF ENDOCRINE DISEASE: l-Thyroxine replacement therapy in the frail elderly: a challenge in clinical practice

The number of elderly people, mostly aged over 85 years (the 'oldest old'), is increasing worldwide. As a consequence, accompanying morbidity and disability have been increasing, and frailty, defined as an age-related condition of decline of physiological reserves and vulnerability, represents an emerging problem. Caring for older frail people may represent a challenge, since the elderly differ significantly from younger adults in terms of comorbidity, polypharmacy, pharmacokinetics and greater vulnerability to adverse drug reactions. Specific criteria of therapeutic appropriateness and modified goals of care are needed in such patients, also in endocrine care settings. Indeed, thyroid dysfunctions are among the most common conditions in older, multimorbid populations. The prevalence of overt and subclinical hypothyroidism is as high as 20% and thyroid hormone prescription is common in the elderly, with a trend toward levothyroxine treatment of more marginal degrees of hypothyroidism. In addition, older patients have the highest rate of overtreatment during replacement therapy and are more susceptible to developing adverse effects from thyroid hormone excess. Recently, results of a multicentric randomized controlled trial, the TRUST-IEMO collaboration trial, added further insights to the debated question of whether and when levothyroxine treatment is required and if it is beneficial in the elderly. With this in mind, we revised the relevant literature on the impact of thyroid dysfunction and replacement therapy among older people, with the aim to better define indications, benefits and risks of l-T4 replacement therapy in the frail elderly.

Recommendations for treatment of hypothyroidism with levothyroxine and levotriiodothyronine: a 2016 position statement of the Italian Society of Endocrinology and the Italian Thyroid Association

Levothyroxine (L-T4) is recommended as lifelong replacement therapy for hypothyroidism. Recent clinical and experimental data support the addition of levotriiodothyronine (L-T3) treatment in some selected hypothyroid patients when their symptoms persist and their quality of life remains impaired despite adequate L-T4 monotherapy. An increase in L-T3 prescriptions has been recently observed in Italy due to availability of different L-T3 formulations, making it possible to clinicians to prescribe L-T3 alone or in combination with L-T4. The aim of the present position statement was to define the correct clinical indications, schedule, duration of treatment and contraindications of combined treatment with L-T4 and L-T3 in hypothyroid patients in an attempt to guide clinicians and to avoid potential adverse effects of overtreatment.

Melanoma targeting with [99mTc(N)(PNP3)]-labeled α-melanocyte stimulating hormone peptide analogs: Effects of cyclization on the radiopharmaceutical properties

The purpose of this study was to evaluate the effect of cyclization on the biological profile of a [^99mTc(N)(PNP3)]-labeled α-melanocyte stimulating hormone peptide analog. A lactam bridge-cyclized H-Cys-Ahx-βAla³-c[Lys⁴-Glu-His-D-Phe-Arg-Trp-Glu¹⁰]-Arg¹¹-Pro-Val-NH₂ (NAP-NS2) and the corresponding linear H-Cys-Ahx-βAla-Nle-Asp-His-D-Phe-Arg-Trp-Gly-NH₂ (NAP-NS1) peptide were synthetized, characterized by ESI-MS spectroscopy and their melanocortin-1 receptor (MC1R) binding affinity was determined in B16/F10 melanoma cells. The consistent [^99mTc(N)(PNP3)]-labeled compounds were readily obtained in high specific activity and their stability and biological properties were assessed. As an example, the chemical identity of [^99mTc(N)(NAP-NS1)(PNP3)]⁺ was confirmed by carrier added experiments supported by radio/UV HPLC analysis combined with ESI(+)-MS. Compared with the linear peptide, cyclization negatively affected the biological properties of NAP-NS2 peptide by reducing its binding affinity for MC1R and by decreasing the overall excretion rate of the corresponding [^99mTc(N)(PNP3)]-labeled peptide from the body as well as its in vivo stability. [^99mTc(N)(NAP-NS1)(PNP3)]⁺ was evaluated for its potential as melanoma imaging probe in murine melanoma model. Data from in vitro and in vivo studies on B16/F10 melanoma model of [^99mTc(N)(NAP-NS1)(PNP3)]⁺ clearly evidenced that the radiolabeled linear peptide keeps its biological properties up on the conjugation to the [^99mTc(N)(PNP3)]-building block. The progressive increase of the tumor-to-nontarget ratios over the time indicates a quite stable interaction between the radio-complex and the MC1R.

18th European Symposium on Radiopharmacy and Radiopharmaceuticals

OP03 Selective extraction of medically-related radionuclides from proton-irradiated thorium targets

V. Radchenko, J.W. Engle, C. Roy, J. Griswold, M.F. Nortier, E.R. Birnbaum, M. Brugh, S. Mirzadeh, K. D. John, M.E. Fassbender

OP04 Comparison of [68Ga]FSC(succ-RGD)3 and [68Ga]NODAGA-RGD for PET imaging of αvβ3 integrin expression

Chuangyan Zhai, Gerben M. Franssen, Milos Petrik, Peter Laverman, Clemens Decristoforo

OP05 A new NPY-Y1R targeting peptide for breast cancer PET imaging

Ait-Mohand Samia, Dumulon-Perreault Véronique, Guérin Brigitte

OP06 The influence of multivalency on CCK 2 receptor targeting

D. Summer, A. Kroess, C. Rangger, H. Haas, P. Laverman, F. Gerben, E. von Guggenberg, C.Decristoforo

OP07 SPECT Imaging of αvβ3 Expression by [99mTc(N)PNP43]- Bifunctional Chimeric RGD Peptide not Cross-Reacting with αvβ5

Cristina Bolzati, Nicola Salvarese, Fiorenzo Refosco, Laura Meléndez-Alafort, Debora Carpanese, Antonio Rosato, Michele Saviano, Annarita Del Gatto, Daniela Comegna, Laura Zaccaro

OP09 New dienophiles for the inverse-electron-demand Diels-Alder reaction and for pretargeted PET imaging

Emilie Billaud, Muneer Ahamed, Frederik Cleeren, Elnaz Shahbazali, Tim Noël, Volker Hessel, Alfons Verbruggen and Guy Bormans

OP10 New complexing agent for Al18F-labelling of heat-sensitive biomolecules: Synthesis and preclinical evaluation of Al18F-RESCA1-HAS

Cleeren F, Lecina J, Koole M, Verbruggen A and Bormans G

OP11 A novel versatile precursor efficient for F-18 radiolabelling via click-chemistry

B. Lugatoa, S. Stucchia, E.A. Turollaa, L. Giulianoa, S.Toddea, P. Ferraboschib

OP12 A general applicable method to quantify unidentified UV impurities in radiopharmaceuticals

R.P. Klok, M.P.J. Mooijer, N.H. Hendrikse, A.D. Windhorst

OP13 Development of [¹⁸F]Fluoro-C-glycosides to radiolabel peptides

Collet C., Petry N., Chrétien F., Karcher G., Pellegrini-Moïse N., Lamandé-Langle S.

OP14 A Microfluidic Approach for the 68Ga-labeling of PSMAHBED-CC and NODAGA-RGD

Sarah Pfaff, Cecile Philippe, Markus Mitterhauser, Marcus Hacker, Wolfgang Wadsak

OP16 Surprising reactivity of astatine in the nucleophilic substitution of aryliodonium salts: application to the radiolabeling of antibodies

François Guérard, Yong-Sok Lee, Sébastien Gouard, Kwamena Baidoo, Cyrille Alliot, Michel Chérel, Martin W. Brechbiel, Jean-François Gestin

OP17 ⁶⁴Cu-NOTA-pertuzumab F(ab')₂ fragments, a second-generation probe for PET imaging of the response of HER2-positive breast cancer to trastuzumab (Herceptin)

Lam K, Chan C, Reilly RM

OP18 Development of radiohalogenated analogues of a avb6-specific peptide for high LET particle emitter targeted radionuclide therapy of cancer

Salomé Paillas, John Marshall, Jean-Pierre Pouget, Jane Sosabowski

OP19 Ligand Specific Efficiency (LSE) as a guide in tracer optimization

Emmanuelle Briard, Yves P. Auberson, John Reilly, Mark Healy, David Sykes

OP23 The radiosynthesis of an 18F-labeled triglyceride, developed to visualize and quantify brown adipose tissue activity

Andreas Paulus, Wouter van Marken Lichtenbelt,Felix Mottaghy, Matthias Bauwens

OP24 Influence of the fluorescent dye on the tumor targeting properties of dual-labeled HBED-CC based PSMA inhibitors

Baranski, Ann-Christin, Schäfer, Martin, Bauder-Wüst, Ulrike, Haberkorn, Uwe, Eder, Matthias, Kopka, Klaus

OP25 [18F]MEL050 as a melanin PET tracer : fully automated radiosynthesis and evaluation for the detection of pigmented melanoma in mice pulmonary metastases

Chaussard M, Hosten B, Vignal N, Tsoupko-Sitnikov V, Hernio N, Hontonnou F, Merlet P, Poyet JL, Sarda-Mantel L, Rizzo-Padoin N

OP26 Design and Preclinical Evaluation of Novel Radiofluorinated PSMA Targeting Ligands Based on PSMA-617

J. Cardinale, M. Schäfer, M. Benešová, U. Bauder-Wüst, O. Seibert, F. Giesel, U. Haberkorn, M. Eder, K. Kopka

OP27 A novel radiolabeled peptide for PET imaging of prostate cancer: 64Cu-DOTHA2-PEG-RM26

Mansour Nematallah, Paquette Michel, Ait-Mohand Samia, Dumulon-Perreault Véronique, Lecomte Roger, Guérin Brigitte

OP29 Biodistribution of [¹⁸F]Amylovis®, a new radiotracer PET imaging of β-amyloid plaques

Fernandez-Maza L, Rivera-Marrero S, Prats Capote A, Parrado-Gallego A, Fernandez-Gomez I, Balcerzyk M, Sablon-Carrazana M, Perera-Pintado A, Merceron-Martinez D, Acosta-Medina E, Rodriguez-Tanty C

OP30 Synthesis and preclinical evaluation of [11C]-BA1 PET tracer for the imaging of CSF-1R

Bala Attili, Muneer Ahamed, Guy Bormans

OP31 In vivo imaging of the MCHR1 in the ventricular system via [18F]FE@SNAP

C. Philippe, M. Zeilinger, T. Scherer, C. Fürnsinn, M. Dumanic, W. Wadsak, M. Hacker, M. Mitterhauser

OP32 Synthesis of the first carbon-11 labelled P2Y12 receptor antagonist for imaging the anti-inflammatory phenotype of activated microglia

B. Janssen, D.J. Vugts, G.T. Molenaar, U. Funke, P.S. Kruijer, F. Dollé, G. Bormans, A.A. Lammertsma, A.D. Windhorst

OP33 Radiosynthesis of a selective HDAC6 inhibitor [11C]KB631 and in vitro and ex vivo evaluation

Koen Vermeulen, Muneer Ahamed, Michael Schnekenburger, Mathy Froeyen, Dag Erlend Olberg, Marc Diederich, Guy Bormansa

OP34 Improving metabolic stability of fluorine-18 labelled verapamil analogues

Raaphorst RM, Luurtsema G, Lammertsma AA, Elsinga PH, Windhorst AD

OP36 Development of a novel PET tracer for the activin receptor-like kinase 5

Lonneke Rotteveel, Uta Funke, Peter ten Dijke, Harm Jan Bogaard, Adriaan A. Lammertsma, Albert D. Windhorst

OP37 SPECT imaging and biodistribution studies of 111In-EGF-Au-PEG nanoparticles in vivo

Lei Song, Sarah Able, Nadia Falzone, Veerle Kersemans, Katherine Vallis

OP38 Melanoma targeting with [99mTc(N)(PNP3)]-labeled NAPamide derivatives: preliminary pharmacological studies

Davide Carta, Nicola Salvarese, Wiebke Sihver, Feng Gao, Hans Jürgen Pietzsch, Barbara Biondi, Paolo Ruzza, Fiorenzo Refosco, Cristina Bolzati

OP39 [⁶⁸Ga]NODAGA-RGD: cGMP synthesis and data from a phase I clinical study

Roland Haubner, Armin Finkensted, Armin Stegmair, Christine Rangger, Clemens Decristoforo, Heinz Zoller, Irene J. Virgolin

OP44 Implementation of a GMP-grade radiopharmacy facility in Maastricht

Ivo Pooters, Maartje Lotz, Roel Wierts, Felix Mottaghy, Matthias Bauwens

OP45 Setting up a GMP production of a new radiopharmaceutical

Forsback, Sarita, Bergman Jörgen, Kivelä Riikka

OP48 In vitro and in vivo evaluation of 68-gallium labeled Fe3O4-DPD nanoparticles as potential PET/MRI imaging agents

M. Karageorgou, M. Radović, C. Tsoukalas, B. Antic, M. Gazouli, M. Paravatou-Petsotas, S. Xanthopouls, M. Calamiotou, D. Stamopoulos, S. Vranješ-Durić, P. Bouziotis

OP49 Fast PET imaging of inflammation using 68Ga-citrate with Fe-containing salts of hydroxy acids

A. S. Lunev, A. A. Larenkov, K.A. Petrosova, O. E. Klementyeva, G. E. Kodina

PP01 Installation and validation of 11C-methionine synthesis

Kvernenes, O.H., Adamsen, T.C.H.

PP02 Fully automated synthesis of 68Ga-labelled peptides using the IBA Synthera® and Synthera® Extension modules

René Martin, Sebastian Weidlich, Anna-Maria Zerges, Cristiana Gameiro, Neva Lazarova, Marco Müllera

PP03 GMP compliant production of ¹⁵O-labeled water using IBA 18 MeV proton cyclotron

Gert Luurtsema, Michèl de Vries, Michel Ghyoot, Gina van der Woude, Rolf Zijlma, Rudi Dierckx, Hendrikus H. Boersma, Philip H. Elsinga

PP04 In vitro Nuclear Imaging Potential of New Subphthalocyanine and Zinc Phthalocyanine

Fatma Yurt Lambrecht, Ozge Er, Mine Ince, Cıgır Biray Avci, Cumhur Gunduz, Fatma Aslihan Sarı

PP05 Synthesis, Photodynamic Therapy Efficacy and Nuclear Imaging Potential of Zinc Phthalocyanines

Kasim Ocakoglu, Ozge Er, Onur Alp Ersoz, Fatma Yurt Lambrecht, Mine Ince, Cagla Kayabasi, Cumhur Gunduz

PP06 Radio-U(H)PLC – the Search on the Optimal Flow Cell for the γ-Detector

Torsten Kniess, Sebastian Meister, Steffen Fischer, Jörg Steinbach

PP07 Radiolabeling, characterization & biodistribution study of cysteine and its derivatives with Tc99m

Rabia Ashfaq, Saeed Iqbal, Atiq-ur-Rehman, Irfan ullah Khan

PP08 Radiolabelling of poly (lactic-co.glycolic acid) (PLGA) nanoparticles with 99mTC

R Iglesias-Jerez, Cayero-Otero, L. Martín-Banderas, A. Perera-Pintado, I. Borrego-Dorado

PP09 Development of [¹⁸F]PD-410 as a non-peptidic PET radiotracer for gastrin releasing peptide receptors

Ines Farinha-Antunes, Chantal Kwizera, Enza Lacivita, Ermelinda Lucente, Mauro Niso, Paola De Giorgio, Roberto Perrone, Nicola A. Colabufo, Philip H. Elsinga, Marcello Leopoldo

PP10 An improved nucleophilic synthesis of 2-(3,4-dimethoxyphenyl)-6-(2-[18F]fluoroethoxy) benzothiazole ([18F]FEDMBT), potential diagnostic agent for breast cancer imaging by PET

V.V. Vaulina, O.S. Fedorova, V.V. Orlovskaja, С.L. Chen, G.Y. Li, F.C. Meng, R.S. Liu, H.E. Wang, R.N. Krasikova

PP11 Internal radiation dose assessment of radiopharmaceuticals prepared with accelerator-produced 99mTc

Laura Meléndez-Alafort, Mohamed Abozeid, Guillermina Ferro-Flores, Anna Negri, Michele Bello, Nikolay Uzunov, Martha Paiusco, Juan Esposito, Antonio Rosato

PP12 A specialized five-compartmental model software for pharmacokinetic parameters calculation

Laura Meléndez-Alafort, Cristina Bolzati, Guillermina Ferro-Flores, Nicola Salvarese, Debora Carpanese, Mohamed Abozeid, Antonio Rosato, Nikolay Uzunov

PP13 Molecular imaging of the pharmacokinetic behavior of low molecular weight ¹⁸F-labeled PEtOx in comparison to ⁸⁹Zr-labeled PEtOx

Palmieri L, Verbrugghen T, Glassner M, Hoogenboom R, Staelens S, Wyffels L

PP14 Towards nucleophilic synthesis of the α-[18F]fluoropropyl-L-dihydroxyphenylalanine

V. V. Orlovskaja, O. F. Kuznetsova, O. S. Fedorova, V. I. Maleev, Yu. N. Belokon, A. Geolchanyan, A. S. Saghyan, L. Mu, R. Schibli, S. M. Ametamey, R. N. Krasikova

PP15 A convenient one-pot synthesis of [18F]clofarabine

Revunov, Evgeny, Malmquist, Jonas, Johnström, Peter, Van Valkenburgh, Juno, Steele, Dalton, Halldin, Christer, Schou, Magnus

PP16 BODIPY-estradiol conjugates as multi-modality tumor imaging agents

Samira Osati,Michel Paquette,Simon Beaudoin,Hasrat Ali,Brigitte Guerin, Jeffrey V. Leyton, Johan E. van Lier

PP17 Easy and high yielding synthesis of 68Ga-labelled HBED-PSMA and DOTA-PSMA by using a Modular-Lab Eazy automatic synthesizer

Di Iorio V, Iori M, Donati C, Lanzetta V, Capponi PC, Rubagotti S, Dreger T, Kunkel F, Asti M

PP18 Synthesis and evaluation of fusarinine C-based octadentate bifunctional chelators for zirconium-89 labelling

Chuangyan Zhai, Christine Rangger, Dominik Summer, Hubertus Haas, Clemens Decristoforo

PP19 Fully automated production of [18F]NaF using a re-configuring FDG synthesis module.

Suphansa Kijprayoon, Ananya Ruangma, Suthatip Ngokpol, Samart Tuamputsha

PP20 Extension of the Carbon-11 Small Labeling Agents Toolbox and Conjugate Addition

Ulrike Filp, Anna Pees, Carlotta Taddei, Aleksandra Pekošak, Antony D. Gee, Alex J. Poot, Albert D. Windhorst

PP21 In vitro studies on BBB penetration of pramipexole encapsulated theranostic liposomes for the therapy of Parkinson’s disease

Mine Silindir Gunay, A. Yekta Ozer, Suna Erdogan, Ipek Baysal, Denis Guilloteau, Sylvie Chalon

PP22 Factors affecting tumor uptake of 99mTc-HYNIC-VEGF165

Filippo Galli, Marco Artico, Samanta Taurone, Enrica Bianchi, Bruce D. Weintraub, Mariusz Skudlinski, Alberto Signore

PP23 Rhenium-188: a suitable radioisotope for targeted radiotherapy

Nicolas Lepareur, Nicolas Noiret, François Hindré, Franck Lacœuille, Eric Benoist, Etienne Garin

PP24 Preparation of a broad palette of 68Ga radiopharmaceuticals for clinical applications

Trejo-Ballado F, Zamora-Romo E, Manrique-Arias JC, Gama-Romero HM, Contreras-Castañon G, Tecuapetla-Chantes RG, Avila-Rodriguez MA

PP25 68Ga-peptide preparation with the use of two 68Ge/68Ga-generators

H. Kvaternik, D. Hausberger, C. Zink, B. Rumpf, R. M. Aigner

PP26 Assay of HEPES in 68Ga-peptides by HPLC

H. Kvaternik, D. Hausberger, B. Rumpf, R. M. Aigner

PP27 Preparation, in vitro and in vivo evaluation of a 99mTc(I)-Diethyl Ester (S,S)-Ethylenediamine- N,N´-DI-2-(3-Cyclohexyl) Propionic acid as a target-specific radiopharmaceutical

Drina Janković, Mladen Lakić, Aleksandar Savić, Slavica Ristić, Nadežda Nikolić, Aleksandar Vukadinović, Tibor J. Sabo, Sanja Vranješ-Đurić

PP28 90Y-labeled magnetite nanoparticles for possible application in cancer therapy

S. Vranješ-Đurić, M. Radović, D. Janković, N. Nikolić, G. F. Goya, P. Calatayud, V. Spasojević, B. Antić

PP29 Simplified automation of the GMP production of 68Ga-labelled peptides

David Goblet, Cristiana Gameiro, Neva Lazarova

PP30 Combining commercial production of multi-products in a GMP environment with Clinical & R&D activities

Cristiana Gameiro, Ian Oxley, Antero Abrunhosa, Vasko Kramer, Maria Vosjan, Arnold Spaans

PP31 ⁹⁹mTc(CO)3-labeling and Comparative In-Vivo Evaluation of Two Clicked cRGDfK Peptide Derivatives

Kusum Vats, Drishty Satpati, Haladhar D Sarma, Sharmila Banerjee

PP32 Application of AnaLig resin for 99mTc separation from molybdenum excess

Wojdowska W., Pawlak D.W., Parus L. J., Garnuszek P., Mikołajczak R.

PP33 Constraints for selection of suitable precursor for one-step automated synthesis of [18F]FECNT, the dopamine transporter ligand

Pijarowska-Kruszyna J, Jaron A, Kachniarz A, Malkowski B, Garnuszek P, Mikolajczak R

PP34 Gamma scintigraphy studies with 99mTc- amoxicillin sodium in bacterially infected and sterile inflamed rats

Derya Ilem-Ozdemir, Oya Caglayan-Orumlu, Makbule Asikoglu

PP35 Preparation of 99mTc- Amoxicillin Sodium Lyophilized Kit

Derya Ilem-Ozdemir, Oya Caglayan-Orumlu, Makbule Asikoglu

PP36 Outfits of Tracerlan FXC-PRO for 11C-Labeling

Arponen Eveliina, Helin Semi, Saarinen Timo, Vauhkala Simo, Kokkomäki Esa, Lehikoinen Pertti

PP37 Microfluidic synthesis of ω-[18F]fluoro-1-alkynes

Mariarosaria De Simone, Giancarlo Pascali, Ludovica Carzoli, Mauro Quaglierini, Mauro Telleschi, Piero A. Salvadori

PP38 Automated 18F-flumazenil production using chemically resistant disposable cassettes

Phoebe Lam, Martina Aistleitner, Reinhard Eichinger, Christoph Artner

PP39 The effect of the eluent solutions (TBAHCO3, Kryptand K2.2.2) on the radiochemical yields of 18F-Fluoromethylcholine

Surendra Nakka, Hemantha Kumara MC, Al-Qahtani Mohammed

PP40 [68Ga]Radiolabeling of short peptide that has a PET imaging potentials

Al-Qahtani, Mohammed, Al-Malki, Yousif

PP41 Is validation of radiochemical purity analysis in a public hospital in a developing country possible?

N Mambilima, SM Rubow

PP42 Improved automated radiosynthesis of [18F]FEPPA

N. Berroterán-Infante, M. Hacker, M. Mitterhauser, W. Wadsak

PP43 Synthesis and initial evaluation of Al18F-RESCA1-TATE for somatostatin receptor imaging with PET

Uta Funke, Frederik Cleeren, Joan Lecina, Rodrigo Gallardo, Alfons M. Verbruggen, Guy Bormans

PP44 Radiolabeling and SPECT/CT imaging of different polymer-decorated zein nanoparticles for oral administration

Rocío Ramos-Membrive, Ana Brotons, Gemma Quincoces, Laura Inchaurraga, Inés Luis de Redín, Verónica Morán, Berta García-García, Juan Manuel Irache, Iván Peñuelas

PP45 An analysis of the quality of 68Ga-DOTANOC radiolabelling over a 3 year period

Trabelsi, M., Cooper M.S.

PP46 In vivo biodistribution of adult human mesenchymal stem cells I (MSCS-ah) labeled with 99MTC-HMPAO administered via intravenous and intra-articular in animal model. Preliminary results

Alejandra Abella, Teodomiro Fuente, Antonio Jesús Montellano, Teresa Martínez, Ruben Rabadan, Luis Meseguer-Olmo

PP47 Synthesis of [¹⁸F]F-exendin-4 with high specific activity

Lehtiniemi P, Yim C, Mikkola K, Nuutila P, Solin O

PP48 Experimental radionuclide therapy with 177Lu-labelled cyclic minigastrin and human dosimetry estimations

von Guggenberg E, Rangger C, Mair C, Balogh L, Pöstényi Z, Pawlak D, Mikołajczak R

PP49 Synthesis of radiopharmaceuticals for cell radiolabelling using anion exchange column

Socan A, Kolenc Peitl P, Krošelj M, Rangger C, Decristoforo C

PP50 [68Ga]peptide production on commercial synthesiser mAIO

Collet C., Remy S., Didier R,Vergote T.,Karcher G., Véran N.

PP51 Dry kit formulation for efficient radiolabeling of 68Ga-PSMA

D. Pawlak, M. Maurin, P. Garnuszek, U. Karczmarczyk, R. Mikołajczak

PP52 Development of an experimental method using Cs-131 to evaluate radiobiological effects of internalized Auger-electron emitters

Pil Fredericia, Gregory Severin, Torsten Groesser, Ulli Köster, Mikael Jensen

PP53 Preclinical comparative evaluation of NOTA/NODAGA/DOTA CYCLO-RGD peptides labelled with Ga-68

R. Leonte, F. D. Puicea, A. Raicu, E. A. Min, R. Serban, G. Manda, D. Niculae

PP54 Synthesizer- and Kit-based preparation of prostate cancer imaging agent 68Ga-RM2

Marion Zerna, Hanno Schieferstein, Andre Müller, Mathias Berndt

PP55 Synthesis of pancreatic beta cell-specific [18F]fluoro-exendin-4 via strain-promoted aza-dibenzocyclooctyne/azide cycloaddition

Cheng-Bin Yim, Kirsi Mikkola, Pirjo Nuutila, Olof Solin

PP56 Automated systems for radiopharmacy

D. Seifert, J. Ráliš, O. Lebeda

PP57 Simple, suitable for everyday routine use quality control method to assess radionuclidic purity of cyclotron-produced 99mTc

Svetlana V. Selivanova, Helena Senta, Éric Lavallée, Lyne Caouette, Éric Turcotte, Roger Lecomte

PP58 Effective dose estimation using Monte Carlo simulation for patients undergoing radioiodine therapy

Marina Zdraveska Kochovska, Emilija Janjevik Ivanovska, Vesna Spasic Jokic

PP59 Chemical analysis of the rituximab radioimmunoconjugates in lyophilized formulations intended for oncological applications

Darinka Gjorgieva Ackova, Katarina Smilkov, Petre Makreski, Trajče Stafilov, Emilija Janevik-Ivanovska

PP61 The need and benefits of established radiopharmacy in developing African countries

Aschalew Alemu, Joel Munene Muchira, David Mwanza Wanjeh, Emilija Janevik-Ivanovska

PP62 University Master Program of Radiopharmacy – step forward for Good Radiopharmacy Education

Emilija Janevik-Ivanovska, Zoran Zdravev, Uday Bhonsle, Osso Júnior João Alberto, Adriano Duatti, Bistra Angelovska, Zdenka Stojanovska, Zorica Arsova Sarafinovska, Darko Bosnakovski, Darinka Gorgieva-Ackova, Katarina Smilkov, Elena Drakalska, Meera Venkatesh, Rubin Gulaboski

PP63 Synthesis and preclinical validations of a novel 18F-labelled RGD peptide prepared by ligation of a 2-cyanobenzothiazole with 1,2-aminothiol to image angiogenesis.

Didier J. Colin, James A. H. Inkster, Stéphane Germain, Yann Seimbille

The rational search for selective anticancer derivatives of the peptide Trichogin GA IV: a multi-technique biophysical approach

Peptaibols are peculiar peptides produced by fungi as weapons against other microorganisms. Previous studies showed that peptaibols are promising peptide-based drugs because they act against cell membranes rather than a specific target, thus lowering the possibility of the onset of multi-drug resistance, and they possess non-coded α-amino acid residues that confer proteolytic resistance. Trichogin GA IV (TG) is a short peptaibol displaying antimicrobial and cytotoxic activity. In the present work, we studied thirteen TG analogues, adopting a multidisciplinary approach. We showed that the cytotoxicity is tuneable by single amino-acids substitutions. Many analogues maintain the same level of non-selective cytotoxicity of TG and three analogues are completely non-toxic. Two promising lead compounds, characterized by the introduction of a positively charged unnatural amino-acid in the hydrophobic face of the helix, selectively kill T67 cancer cells without affecting healthy cells. To explain the determinants of the cytotoxicity, we investigated the structural parameters of the peptides, their cell-binding properties, cell localization, and dynamics in the membrane, as well as the cell membrane composition. We show that, while cytotoxicity is governed by the fine balance between the amphipathicity and hydrophobicity, the selectivity depends also on the expression of negatively charged phospholipids on the cell surface.

An insight into the metal coordination and spectroscopic properties of artistic Fe and Fe/Cu logwood inks

Fe- and Fe/Cu-based logwood inks were synthesized following recipes in nineteenth and early twentieth century manuals and were characterized by EPR, ESI-MS, FTIR, and Raman spectroscopies. This multi-technique approach allowed us to shed light on the structures of the complexes responsible for the inks' colors and to obtain vibrational signatures that can be used to identify the different inks in works of art and in historic documents. Information on the nature and chemical properties of the complexes formed between a dye and a mordant is important as these determine, at least in part, their lightfastness. EPR permitted to determine the coordination environment of the metallic ions. The results of the ESI-MS analysis demonstrated, for the first time, the breakdown of the hematein molecule during the ink preparation, and that the colorants are formed by the complexation of the metallic ions by hematein breakdown products, mainly catechol and/or bicyclic compounds. The FTIR spectra obtained were found to be dominated by bands due to the binding medium and sulfates used as reagents. The Raman analysis showed that the characteristic features for the different inks studied depend on the historic recipe used, attesting to the challenges that their identification and characterization in works of art present. In the Raman spectra of the inks applied on paper, broadening of bands in the 750-400 cm(-1) range are observed when compared to the spectra of the inks' powders, possibly due to the interaction of the compounds with the cellulose in the substrate.

Shaping bioinspired photo-responsive microstructures by the light-driven modulation of selective interactions

The selective adenine–thymine binding occurring between complementary self-organized complex systems can be modulated by the activation of the plasmon resonance.

Comparison of bactericidal and cytotoxic activities of trichogin analogs

Peptaibiotics are a group of membrane active peptides of fungal origin. They typically contain α-aminoisobutyric acid (Aib; 1-letter code, U) and other non-coded residues (Toniolo and Brückner, 2009; Neumann et al., 2015; Benedett et al., 1982) [1], [2], [3] stabilizing their helical structure. Peptaibols are peptaibiotics carrying a 1, 2-aminoalcohol at the C-terminus. When a fatty acid chain (of 8–10 carbon atoms) is present at their N-terminus, they are called lipopeptaibols (Toniolo et al., 2001; Degenkolb et al., 2003) [4], [5]. We found (Tavano et al., 2015) [6] that the lipopeptaibol trichogin displays no antibacterial effects up to 64 µM, against both Gram⁻ and Gram⁺ bacteria, but kills tumor and healthy human cells via a mechanism requiring both the C-terminal primary alcohol group and the N-terminal n-octanoyl moiety, with EC50s around 4–5 µM. However, the substitution of single Gly residues with Lys strongly improves anti-Gram⁺ activity (Tavano et al., 2015; De Zotti, Biondi, Park et al., 2012; De Zotti, Biondi, Peggion et al., 2012) [6], [7], [8]. To further characterize the activity of trichogin analogs as antibiotics and cytotoxic agents, we here manipulated the peptide helix amphipathicity by means of two different substitutions: (i) Aib to Leu (De Zotti et al., 2012) [7] or (ii) multiple Gly to Lys changes (Tavano et al., 2015; De Zotti, Biondi, Park et al., 2012; De Zotti, Biondi, Peggion, Formaggio et al., 2012; De Zotti, Biondi, Peggion, De Poli et al., 2012) [6], [7], [8], [9]. The antibacterial activity against four commensal or opportunistic bacterial species and the cytotoxicity against a panel of 9 healthy and tumor-derived eukaryotic cell types (including erythrocytes) are reported as MIC and EC50 (MTS - [3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)]-2H-tetrazolium- reduction and LDH - lactate dehydrogenase - release assay).

Effects of Trehalose on Thermodynamic Properties of Alpha-synuclein Revealed through Synchrotron Radiation Circular Dichroism

Many neurodegenerative diseases, including Huntington’s, Alzheimer’s and Parkinson’s diseases, are characterized by protein misfolding and aggregation. The capability of trehalose to interfere with protein misfolding and aggregation has been recently evaluated by several research groups. In the present work, we studied, by means of synchrotron radiation circular dichroism (SRCD) spectroscopy, the dose-effect of trehalose on α-synuclein conformation and/or stability to probe the capability of this osmolyte to interfere with α-synuclein’s aggregation. Our study indicated that a low trehalose concentration stabilized α-synuclein folding much better than at high concentration by blocking in vitro α-synuclein’s polymerisation. These results suggested that trehalose could be associated with other drugs leading to a new approach for treating Parkinson’s and other brain-related diseases.

Cytopathologists can reliably perform ultrasound-guided thyroid fine needle aspiration: a 1-year audit on 3715 consecutive cases

OBJECTIVE

In our Pathology Department, fine needle aspiration (FNA) of palpable thyroid nodules is performed by cytopathologists who ensure correct sample management and rapid on-site evaluation (ROSE). Conversely, ultrasound (US)-guided FNAs have traditionally been carried out by endocrinologists and radiologists in outside clinics, where the presence of a cytopathologist is not always feasible. To overcome this limitation, cytopathologists have started to perform US-guided FNAs themselves. This study retrospectively evaluates 1 year of this novel practice.

METHODS

A total of 2225 US-guided FNAs were performed in our clinic by cytopathologists, whereas 1490 aspirates were taken by a group of non-cytopathologists. Among these, 756 FNAs were taken by a single experienced endocrinologist. The distribution of the Bethesda classification categories was evaluated in each of these groups.

RESULTS

FNAs performed by cytopathologists were more often diagnostic and better prepared than those taken by non-cytopathologists, including those taken by the experienced endocrinologist (P < 0.01). The latter operator yielded a higher rate of suspicious and malignant FNAs, reflecting a more appropriate clinical triage of worrisome nodules.

CONCLUSION

Although the endocrinologist's evaluation is crucial to select clinically relevant thyroid nodules, cytopathologists can reliably perform US guidance in addition to their traditional expertise in sampling, specimen preparation and ROSE.