Surgical approach to a rare case of Beckwith Wiedemann syndrome with left thigh hyperplasia

Thigh lift surgery is generally performed in patients with severe weight loss outcomes, particularly those undergoing bariatric surgery. However, there are other congenital malformation conditions that may require the same treatment, such as Beckwith Wideman syndrome.

On the mechanism of action of arsenoplatins: arsenoplatin-1 binding to a B-DNA dodecamer

The reaction of Pt-based anticancer agents with arsenic trioxide affords robust complexes known as arsenoplatins. The prototype of this family of anticancer compounds is arsenoplatin-1 (AP-1) that contains an As(OH)2 fragment linked to a Pt(II) moiety derived from cisplatin. Crystallographic and spectrometric studies of AP-1 binding to a B-DNA double helix dodecamer are presented here, in comparison with cisplatin and transplatin. Results reveal that AP-1, cisplatin and transplatin react differently with the DNA model system. Notably, in the AP-1/DNA systems, the Pt-As bond can break down with time and As-containing fragments can be released. These results have implications for the understanding of the mechanism of action of arsenoplatins.

A Diruthenium Metallodrug as a Potent Inhibitor of Amyloid-β Aggregation: Synergism of Mechanisms of Action

The physical and chemical properties of paddlewheel diruthenium compounds are highly dependent on the nature of the ligands surrounding the bimetallic core. Herein, we compare the ability of two diruthenium compounds, [Ru2Cl(D-p-FPhF)(O2CCH3)3]·H2O (1) (D-p-FPhF- = N,N'-bis(4-fluorophenyl)formamidinate) and K3[Ru2(O2CO)4]·3H2O (2), to act as inhibitors of amyloid aggregation of the Aβ1-42 peptide and its peculiar fragments, Aβ1-16 and Aβ21-40. A wide range of biophysical techniques has been used to determine the inhibition capacity against aggregation and the possible mechanism of action of these compounds (Thioflavin T fluorescence and autofluorescence assays, UV-vis absorption spectroscopy, circular dichroism, nuclear magnetic resonance, mass spectrometry, and electron scanning microscopy). Data show that the most effective inhibitory effect is shown for compound 1. This compound inhibits fiber formation and completely abolishes the cytotoxicity of Aβ1-42. The antiaggregatory capacity of this complex can be explained by a binding mechanism of the dimetallic units to the peptide chain along with π-π interactions between the formamidinate ligand and the aromatic side chains. The results suggest the potential use of paddlewheel diruthenium complexes as neurodrugs and confirm the importance of the steric and charge effects on the properties of diruthenium compounds.

Structural insights and aggregation propensity of a super-stable monellin mutant: A new potential building block for protein-based nanostructured materials

Protein fibrillation is commonly associated with pathologic amyloidosis. However, under appropriate conditions several proteins form fibrillar structures in vitro that can be used for biotechnological applications. MNEI and its variants, firstly designed as single chain derivatives of the sweet protein monellin, are also useful models for protein fibrillary aggregation studies. In this work, we have drawn attention to a protein dubbed Mut9, already characterized as a "super stable" MNEI variant. Comparative analysis of the respective X-ray structures revealed how the substitutions present in Mut9 eliminate several unfavorable interactions and stabilize the global structure. Molecular dynamic predictions confirmed the presence of a hydrogen-bonds network in Mut9 which increases its stability, especially at neutral pH. Thioflavin-T (ThT) binding assays and Fourier transform infrared (FTIR) spectroscopy indicated that the aggregation process occurs both at acidic and neutral pH, with and without addition of NaCl, even if with a different kinetics. Accordingly, Transmission Electron Microscopy (TEM) showed a fibrillar organization of the aggregates in all the tested conditions, albeit with some differences in the quantity and in the morphology of the fibrils. Our data underline the great potential of Mut9, which combines great stability in solution with the versatile conversion into nanostructured biomaterials.

Steric hindrance and charge influence on the cytotoxic activity and protein binding properties of diruthenium complexes

Paddlewheel diruthenium complexes are being used as metal-based drugs. It has been proposed that their charge and steric properties determine their selectivity towards proteins. Here, we explore these parameters using the first water-soluble diruthenium complex bearing two formamidinate ligands, [Ru2Cl(DPhF)2(O2CCH3)2], and two derivatives, [Ru2Cl(DPhF)(O2CCH3)3] and K2[Ru2(DPhF)(CO3)3] (DPhF- = N,N'-diphenylformamidinate), with one formamidinate. Their protein binding properties have been assessed employing hen egg white lysozyme (HEWL). The results confirm the relationship between the type of interaction (coordinate/non-coordinate bonds) and the charge of diruthenium complexes. The crystallization medium is also a key factor. In all cases, diruthenium species maintain the M-M bond and produce stable adducts. The antiproliferative properties of these diruthenium complexes have been evaluated on an eukaryotic cell-based model. Our data show a correlation between the number of the formamidinate ligands and the anticancer activity of the diruthenium derivatives against human epithelial carcinoma cells. Increased cytotoxicity may be related to increased steric hindrance and Ru25+ core electronic density. However, the effect of increasing the lipophilicity of diruthenium species by introducing a second N,N'-diphenylformamidinate must be also considered. This work illustrates a systematic approach to shed light on the relevant properties of diruthenium compounds to design metal-based metallodrugs and diruthenium metalloenzymes.

Stabilization and Binding of [V4 O12 ]4- and Unprecedented [V20 O54 (NO3 )]n- to Lysozyme upon Loss of Ligands and Oxidation of the Potential Drug VIV O(acetylacetonato)2

High-resolution crystal structures of lysozyme in the presence of the potential drug VIV O(acetylacetonato)2 under two different experimental conditions have been solved. The crystallographic study reveals the loss of the ligands, the oxidation of VIV to VV and the subsequent formation of adducts of the protein with two different polyoxidovanadates: [V4 O12 ]4- , which interacts with lysozyme non-covalently, and the unprecedented [V20 O54 (NO3 )]n- , which is covalenty bound to the side chain of an aspartate residue of symmetry related molecules.

A model eye for fluorescent characterization of retinal cultures and tissues

Many human neural or neurodegenerative diseases strongly affect the ocular and retinal environment showing peculiar alterations which can be employed as specific disease biomarkers. The noninvasive optical accessibility of the retina makes the ocular investigation a potentially competitive strategy for screening, thus the development of retinal biomarkers is rapidly growing. Nevertheless, a tool to study and image biomarkers or biological samples in a human-like eye environment is still missing. Here we report on a modular and versatile eye model designed to host biological samples, such as retinal cultures differentiated from human induced pluripotent stem cells and ex-vivo retinal tissue, but also suited to host any kind of retinal biomarkers. We characterized the imaging performance of this eye model on standard biomarkers such as Alexa Fluor 532 and Alexa Fluor 594.

Cisplatin binding to angiogenin protein: new molecular pathways and targets for the drug's anticancer activity

Cisplatin (CisPt), a platinum-based chemotherapeutic widely used in the treatment of various cancers, has multiple mechanisms of action, including nuclear DNA (nDNA) and mitochondrial DNA (mDNA) damage and cytoskeletal perturbations affecting, in turn, the membrane transporter activity. CisPt binding to proteins and enzymes may modulate its biochemical mechanism of action and is associated with cancer cell resistance to the drug. In this work, we investigate the interaction between cisplatin and angiogenin (Ang), a protein strongly expressed in many types of cancer and a potent angiogenic factor. The adduct formed upon reaction of CisPt with Ang (Ang@CisPt) was characterized by X-ray crystallography to evidence the exact platination site and by UV-visible (UV-vis) absorption and circular dichroism (CD) spectroscopies to shed light on any possible change in the protein conformation. Furthermore, high-resolution electrospray ionization (ESI) mass spectrometry was utilized to evaluate the Ang : CisPt stoichiometry of the Ang@CisPt adduct. The effect of the Ang@CisPt adduct on a prostate cancer cell line (PC-3) was tested by colorimetric assays in terms of cell viability, at both levels of nuclear and mitochondrial damage, and reactive oxygen species (ROS) production. Cellular imaging by laser scanning confocal microscopy (LSM) was utilized to scrutinize the cytoskeleton actin reorganization and the lysosome and mitochondria organelle perturbation. These studies highlight the possibility of new molecular pathways and targets for CisPt activity.

Dirhodium tetraacetate binding to a B-DNA double helical dodecamer probed by X-ray crystallography and mass spectrometry

The reaction of the cytotoxic compound dirhodium tetraacetate with a B-DNA double helical dodecamer was studied by X-ray crystallography and mass spectrometry. The structure of the dirhodium/DNA adduct reveals a dimetallic center binding to an adenine via axial coordination. Complementary information has been gained through ESI MS measurements. Comparison between the present data and those previously obtained for cisplatin indicates that the two metallodrugs react with this DNA dodecamer in a significantly different fashion.

Implications of Protein Interaction in the Speciation of Potential VIVO-Pyridinone Drugs

Vanadium complexes (VCs) are promising agents for the treatment, among others, of diabetes and cancer. The development of vanadium-based drugs is mainly limited by a scarce knowledge of the active species in the target organs, which is often determined by the interaction of VCs with biological macromolecules like proteins. Here, we have studied the binding of [V^IVO(empp)₂] (where Hempp is 1-methyl-2-ethyl-3-hydroxy-4(1H)-pyridinone), an antidiabetic and anticancer VC, with the model protein hen egg white lysozyme (HEWL) by electrospray ionization-mass spectrometry (ESI-MS), electron paramagnetic resonance (EPR), and X-ray crystallography. ESI-MS and EPR techniques reveal that, in aqueous solution, both the species [V^IVO(empp)₂] and [V^IVO(empp)(H₂O)]⁺, derived from the first one upon the loss of a empp(-) ligand, interact with HEWL. Crystallographic data, collected under different experimental conditions, show covalent binding of [V^IVO(empp)(H₂O)]⁺ to the side chain of Asp48, and noncovalent binding of cis-[V^IVO(empp)₂(H₂O)], [V^IVO(empp)(H₂O)]⁺, [V^IVO(empp)(H₂O)₂]⁺, and of an unusual trinuclear oxidovanadium(V) complex, [V^V₃O₆(empp)₃(H₂O)], with accessible sites on the protein surface. The possibility of covalent and noncovalent binding with different strength and of interaction with various sites favor the formation of adducts with the multiple binding of vanadium moieties, allowing the transport in blood and cellular fluids of more than one metal-containing species with a possible amplification of the biological effects.

A new and efficient procedure to load bioactive molecules within the human heavy-chain ferritin nanocage

For their easy and high-yield recombinant production, their high stability in a wide range of physico-chemical conditions and their characteristic hollow structure, ferritins (Fts) are considered useful scaffolds to encapsulate bioactive molecules. Notably, for the absence of immunogenicity and the selective interaction with tumor cells, the nanocages constituted by the heavy chain of the human variant of ferritin (hHFt) are optimal candidates for the delivery of anti-cancer drugs. hHFt nanocages can be disassembled and reassembled in vitro to allow the loading of cargo molecules, however the currently available protocols present some relevant drawbacks. Indeed, protein disassembly is achieved by exposure to extreme pH (either acidic or alkaline), followed by incubation at neutral pH to allow reassembly, but the final protein recovery and homogeneity are not satisfactory. Moreover, the exposure to extreme pH may affect the structure of the molecule to be loaded. In this paper, we report an alternative, efficient and reproducible procedure to reversibly disassemble hHFt under mild pH conditions. We demonstrate that a small amount of sodium dodecyl sulfate (SDS) is sufficient to disassemble the nanocage, which quantitatively reassembles upon SDS removal. Electron microscopy and X-ray crystallography show that the reassembled protein is identical to the untreated one. The newly developed procedure was used to encapsulate two small molecules. When compared to the existing disassembly/reassembly procedures, our approach can be applied in a wide range of pH values and temperatures, is compatible with a larger number of cargos and allows a higher protein recovery.

Inside out Porphyridium cruentum: Beyond the Conventional Biorefinery Concept

Here, an unprecedented biorefinery approach has been designed to recover high-added value bioproducts starting from the culture ofPorphyridium cruentum. This unicellular marine red alga can secrete and accumulate high-value compounds that can find applications in a wide variety of industrial fields. 300 ± 67 mg/L of exopolysaccharides were obtained from cell culture medium; phycoerythrin was efficiently extracted (40% of total extract) and isolated by single chromatography, with a purity grade that allowed the crystal structure determination at 1.60 Å; a twofold increase in β-carotene yield was obtained from the residual biomass; the final residual biomass was found to be enriched in saturated fatty acids. Thus, for the first time, a complete exploitation ofP. cruentumculture was set up.

Cisplatin Binding to Human Serum Transferrin: A Crystallographic Study

The molecular mechanism of how human serum transferrin (hTF) recognizes cisplatin at the atomic level is still unclear. Here, we report the molecular structure of the adduct formed upon the reaction of hTF with cisplatin. Pt binds the side chain of Met256 (at the N-lobe), without altering the protein overall conformation.

Effect of Equatorial Ligand Substitution on the Reactivity with Proteins of Paddlewheel Diruthenium Complexes: Structural Studies

The paddlewheel [Ru₂Cl(O₂CCH₃)₄] complex was previously reported to react with the model protein hen egg white lysozyme (HEWL), forming adducts with two diruthenium moieties bound to Asp101 and Asp119 side chains upon the release of one acetate. To study the effect of the equatorial ligands on the reactivity with proteins of diruthenium compounds, X-ray structures of the adducts formed when HEWL reacts with [Ru₂Cl(D-p-FPhF)(O₂CCH₃)₃] [D-p-FPhF = N,N'-bis(4-fluorophenyl)formamidinate] under different conditions were solved. [Ru₂Cl(D-p-FPhF)(O₂CCH₃)₃] is bonded through their equatorial positions to the Asp side chains. Protein binding occurs cis or trans to D-p-FPhF. Lys or Arg side chains or even main-chain carbonyl groups can coordinate to the diruthenium core at the axial site. Data help to understand the reactivity of paddlewheel diruthenium complexes with proteins, providing useful information for the design of new artificial diruthenium-containing metalloenzymes with potential applications in the fields of catalysis, biomedicine, and biotechnology.

Multiple and Variable Binding of Pharmacologically Active Bis(maltolato)oxidovanadium(IV) to Lysozyme

The interaction with proteins of metal-based drugs plays a crucial role in their transport, mechanism, and activity. For an active ML_n complex, where L is the organic carrier, various binding modes (covalent and non-covalent, single or multiple) may occur and several metal moieties (M, ML, ML₂, etc.) may interact with proteins. In this study, we have evaluated the interaction of [V^IVO(malt)₂] (bis(maltolato)oxidovanadium(IV) or BMOV, where malt = maltolato, i.e., the common name for 3-hydroxy-2-methyl-4H-pyran-4-onato) with the model protein hen egg white lysozyme (HEWL) by electrospray ionization mass spectrometry, electron paramagnetic resonance, and X-ray crystallography. The multiple binding of different V-containing isomers and enantiomers to different sites of HEWL is observed. The data indicate both non-covalent binding of cis-[VO(malt)₂(H₂O)] and [VO(malt)(H₂O)₃]⁺ and covalent binding of [VO(H₂O)_3–4]²⁺ and cis-[VO(malt)₂] and other V-containing fragments to the side chains of Glu35, Asp48, Asn65, Asp87, and Asp119 and to the C-terminal carboxylate. Our results suggest that the multiple and variable interactions of potential V^IVOL₂ drugs with proteins can help to better understand their solution chemistry and contribute to define the molecular basis of the mechanism of action of these intriguing molecules.

The interaction of [V^IVO(malt)₂] (BMOV, malt = maltolato) with hen egg white lysozyme (HEWL) reveals the multiple binding of different V-containing isomers and enantiomers to different sites and non-covalent and covalent binding of cis-[VO(malt)₂(H₂O)], [VO(malt)(H₂O)₃]⁺, [VO(H₂O)₃₋₄]²⁺, and cis-[VO(malt)₂] to Glu, Asp, and Asn residues.

Protein-Based Delivery Systems for Anticancer Metallodrugs: Structure and Biological Activity of the Oxaliplatin/β-Lactoglobulin Adduct

β-lactoglobulin is the major component of whey. Here, the adduct formed upon the reaction of the protein with oxaliplatin (OXA) has been prepared, structurally characterized by X-ray crystallography and electrospray ionization–mass spectrometry, and evaluated as a cytotoxic agent. The data demonstrate that OXA rapidly binds β-lactoglobulin via coordination with a Met7 side chain upon release of the oxalate ligand. The adduct is significantly more cytotoxic than the free drug and induces apoptosis in cancer cells. Overall, our results suggest that metallodrug/β-lactoglobulin adducts can be used as anticancer agents and that the protein can be used as a metallodrug delivery system.

Halo complexes of gold(i) containing glycoconjugate carbene ligands: synthesis, characterization, cytotoxicity and interaction with proteins and DNA model systems

New neutral Au(i) glycoconjugate carbene complexes show stability in aqueous solutions and interact with both DNA and protein model systems. Cytotoxicity studies demonstrate that the activity depends on the halide ancillary ligand.

Spectroscopic/Computational Characterization and the X-ray Structure of the Adduct of the VIVO-Picolinato Complex with RNase A

The structure, stability, and enzymatic activity of the adduct formed upon the reaction of the V-picolinato (pic) complex [VIVO(pic)2(H2O)], with an octahedral geometry and the water ligand in cis to the V═O group, with the bovine pancreatic ribonuclease (RNase A) were studied. While electrospray ionization-mass spectrometry, circular dichroism, and ultraviolet-visible absorption spectroscopy substantiate the interaction between the metal moiety and RNase A, electron paramagnetic resonance (EPR) allows us to determine that a carboxylate group, stemming from Asp or Glu residues, and imidazole nitrogen from His residues are involved in the V binding at acidic and physiological pH, respectively. Crystallographic data demonstrate that the VIVO(pic)2 moiety coordinates the side chain of Glu111 of RNase A, by substituting the equatorial water molecule at acidic pH. Computational methods confirm that Glu111 is the most affine residue and interacts favorably with the OC-6-23-Δ enantiomer establishing an extended network of hydrogen bonds and van der Waals stabilizations. By increasing the pH around neutrality, with the deprotonation of histidine side chains, the binding of the V complex to His105 and His119 could occur, with that to His105 which should be preferred when compared to that to the catalytically important His119. The binding of the V compound affects the enzymatic activity of RNase A, but it does not alter its overall structure and stability.

Oxaliplatin inhibits angiogenin proliferative and cell migration effects in prostate cancer cells

Angiogenin (Ang) is a potent angiogenic protein that is overexpressed in many types of cancer at concentration values correlated to the tumor aggressiveness. Here, by means of an integrated multi-technique approach based on crystallographic, spectrometric and spectroscopic analyses, we demonstrate that the anti-cancer drug oxaliplatin efficiently binds angiogenin. Microscopy cellular studies, carried out on the prostate cancer cell (PC-3) line , show that oxaliplatin inhibits the angiogenin prompting effect on cell proliferation and migration, which are typical features of angiogenesis process. Overall, our findings point to angiogenin as a possible target of oxaliplatin, thus suggesting a potential novel mechanism for the antineoplastic activity of this platinum drug and opening the avenue to novel approaches in the combined anti-cancer anti-angiogenic therapy.

Interaction of Platinum-based Drugs with Proteins: An Overview of Representative Crystallographic Studies

Pt-based drugs are widely used in clinics for the treatment of cancer. The mechanism of action of these molecules relies on their interaction with DNA. However, the recognition of these metal compounds by proteins plays an important role in defining pharmacokinetics, side effects and their overall pharmacological profiles. Single crystal X-ray diffraction studies provided important information on the molecular mechanisms at the basis of this process. Here, the molecular structures of representative adducts obtained upon reaction with proteins of selected Pt-based drugs, including cisplatin, carboplatin and oxaliplatin, are briefly described and comparatively examined. Data indicate that metal ligands play a significant role in driving the reaction of Pt compounds with proteins; non-covalent interactions that occur in the early steps of Pt compound/protein recognition process play a crucial role in defining the structure of the final Pt-protein adduct. In the metallated protein structures, Pt centers coordinate few protein side chains, such as His, Met, Cys, Asp, Glu and Lys residues upon releasing labile ligands.

Health technology assessment through the six sigma approach in abdominoplasty: Scalpel vs electrosurgery

Abdominoplasty is a surgical procedure conducted to reduce excess abdominal skin and fat and improve body contouring. Despite being commonly performed, it is associated with a risk of complications such as infection, seroma, haematoma and wound dehiscence. To reduce the incidence of complications, different methods are used to create the abdominal flap, i.e., incision with a scalpel or electrosurgery. In this study, health technology assessment (HTA) using the Six Sigma methodology was conducted to compare these incision techniques in patients undergoing abdominoplasty. Two consecutively enroled groups of patients (33 in the scalpel group and 35 in the electrosurgery group) who underwent surgery at a single institution, the University of Campania "Luigi Vanvitelli", were analysed using the drain output as the main outcome for comparison of the incision techniques. While no difference was found regarding haematoma or seroma formation (no cases in either group), the main results also indicate a greater drain output (p-value<0.001) and a greater incidence of dehiscence (p-value=0.056) in patients whose incisions were made through electrosurgery. The combination of HTA and the Six Sigma methodology was useful to prove the possible advantages of creating skin incisions with a scalpel in full abdominoplasty, particularly a significant reduction in the total drain output and a reduction in wound healing problems, namely, wound dehiscence, when compared with electrosurgery, despite considering two limited and heterogeneous groups.

The first step of arsenoplatin-1 aggregation in solution unveiled by solving the crystal structure of its protein adduct

Arsenoplatin-1 (AP-1) is an innovative dual-action anticancer agent that contains a platinum(ii) center coordinated to an arsenous acid moiety. We found that AP-1 spontaneously aggregates in aqueous solutions generating oligomeric species of increasing length. Afterward, we succeeded in solving the crystal structure of the adduct formed between the model protein lysozyme and an early AP-1 oligomer that turned out to be a trimer. Remarkably, this crystal structure traps an early stage of AP-1 aggregation offering detailed insight into the molecular process of the oligomer's growth.

Protein interactions of dirhodium tetraacetate: a structural study

The interactions between the cytotoxic paddlewheel dirhodium complex [Rh2(μ-O2CCH3)4] and the model protein bovine pancreatic ribonuclease (RNase A) were investigated by high-resolution mass spectrometry and X-ray crystallography. The results indicate that [Rh2(μ-O2CCH3)4] extensively reacts with RNase A. The metal compound binds the protein via coordination of the imidazole ring of a His side chain to one of its axial sites, while the dirhodium center and the acetato ligands remain unmodified. Data provide valuable information for the design of artificial dirhodium-containing metalloenzymes.

Pt(II) versus Pt(IV) in Carbene Glycoconjugate Antitumor Agents: Minimal Structural Variations and Great Performance Changes

Octahedral Pt(IV) complexes (2Pt-R) containing a glycoconjugate carbene ligand were prepared and fully characterized. These complexes are structural analogues to the trigonal bipyramidal Pt(II) species (1Pt-R) recently described. Thus, an unprecedented direct comparison between the biological properties of Pt compounds with different oxidation states and almost indistinguishable structural features was performed. The stability profile of the novel Pt(IV) compounds in reference solvents was determined and compared to that of the analogous Pt(II) complexes. The uptake and antiproliferative activities of 2Pt-R and 1Pt-R were evaluated on the same panel of cell lines. DNA and protein binding properties were assessed using human serum albumin, the model protein hen egg white lysozyme, and double stranded DNA model systems by a variety of experimental techniques, including UV-vis absorption spectroscopy, fluorescence, circular dichroism, and electrospray ionization mass spectrometry. Although the compounds present similar structures, their in-solution stability, cellular uptake, and DNA binding properties are diverse. These differences may represent the basis of their different cytotoxicity and biological activity.

A thermophilic C-phycocyanin with unprecedented biophysical and biochemical properties

C-phycoyanins are abundant light-harvesting pigments which have an important role in the energy transfer cascade of photosystems in prokaryotic cyanobacteria and eukaryotic red algae. These proteins have important biotechnological applications, since they can be used in food, cosmetics, nutraceutical, pharmaceutical industries and in biomedical research. Here, C-phycocyanin from the extremophilic red alga Galdieria phlegrea (GpPC) has been purified and characterized from a biophysical point of view by SDS-PAGE, mass spectrometry, UV-Vis absorption spectroscopy, circular dichroism and intrinsic fluorescence. Stability against pH variations, addition of the oxidizing agent hydrogen peroxide and the effects of temperature have been also investigated, together with its in cell antioxidant potential and antitumor activity. GpPC is stable under different pHs and unfolds at a temperature higher than 80 °C within the pH range 5.0-7.0. Its fluorescence spectra present a maximum at 650 nm, when excited at 589 nm. The protein exerts interesting in cell antioxidant properties even after high temperature treatments, like the pasteurization process, and is cytotoxic for A431 and SVT2 cancer cells, whereas it is not toxic for non-malignant cells. Our results assist in the development of C-phycocyanin as a multitasking protein, to be used in the food industry, as antioxidant and anticancer agent.

Label-free quantitative proteomics of the MCF-7 cellular response to a ferritin–metallodrug complex

Schematic summary of the experimental workflow based on label-free quantitative proteomics.

Cisplatin binding to β-lactoglobulin: a structural study

The first structural study on the interaction of β-lactoglobulin with the anticancer compound cisplatin is here reported by combining spectroscopic, crystallographic and mass spectrometry techniques.

Hyaluronic acid fillers in lip augmentation procedure: a clinical and histological study

Several approaches have been proposed for soft tissue augmentation using injectable materials for lip and soft-tissue augmentation due to their physical and biological properties. Hyaluronic acid represents a natural component of the connective tissues, related to wound healing and skin regeneration. The aim of this research was to investigate the clinical and histological effectiveness of cross-linked hyaluronic acid for lip augmentation. A total of 8 patients were treated for lip augmentation with a clinical follow up of 60 days. After this period a histological evaluation was performed to evaluate the healing of the treated regions. The healing phase reported no inflammatory response, tissue contractions and no local flogistic evidence in the treated areas, where the filling volume appeared maintained. The 60 days histological evaluation showed evidence of filler resorption with few infiltrated inflammatory cells. The clinical and histological findings suggested that cross-linked hyaluronic acid represents a safe and effective tool for lip augmentation.

The non-swapped monomeric structure of the arginine-binding protein from Thermotoga maritima

Domain swapping is a widespread oligomerization process that is observed in a large variety of protein families. In the large superfamily of substrate-binding proteins, non-monomeric members have rarely been reported. The arginine-binding protein from Thermotoga maritima (TmArgBP), a protein endowed with a number of unusual properties, presents a domain-swapped structure in its dimeric native state in which the two polypeptide chains mutually exchange their C-terminal helices. It has previously been shown that mutations in the region connecting the last two helices of the TmArgBP structure lead to the formation of a variety of oligomeric states (monomers, dimers, trimers and larger aggregates). With the aim of defining the structural determinants of domain swapping in TmArgBP, the monomeric form of the P235GK mutant has been structurally characterized. Analysis of this arginine-bound structure indicates that it consists of a closed monomer with its C-terminal helix folded against the rest of the protein, as typically observed for substrate-binding proteins. Notably, the two terminal helices are joined by a single nonhelical residue (Gly235). Collectively, the present findings indicate that extending the hinge region and conferring it with more conformational freedom makes the formation of a closed TmArgBP monomer possible. On the other hand, the short connection between the helices may explain the tendency of the protein to also adopt alternative oligomeric states (dimers, trimers and larger aggregates). The data reported here highlight the importance of evolutionary control to avoid the uncontrolled formation of heterogeneous and potentially harmful oligomeric species through domain swapping.

Role of the Metal Center in the Modulation of the Aggregation Process of Amyloid Model Systems by Square Planar Complexes Bearing 2-(2'-pyridyl)benzimidazole Ligands

The effect of analogue Pd(II)-, Pt(II)-, and Au(III) compounds featuring 2-(2'-pyridyl)benzimidazole on the aggregation propensity of amyloid-like peptides derived from Aβ and from the C-terminal domain of nucleophosmin 1 was investigated. Kinetic profiles of aggregation were evaluated using thioflavin binding assays, whereas the interactions of the compounds with the peptides were studied by UV-Vis absorption spectroscopy and electrospray ionization mass spectrometry. The results indicate that the compounds modulate the aggregation of the investigated peptides using different mechanisms, suggesting that the reactivity of the metal center and the physicochemical properties of the metals (rather than those of the ligands and the geometry of the metal compounds) play a crucial role in determining the anti-aggregation properties.

Ferritin-based anticancer metallodrug delivery: Crystallographic, analytical and cytotoxicity studies

The encapsulation of anticancer metal-based drugs within a protein nanocage represents a valuable strategy to improve the efficacy and selectivity of these compounds towards cancer cells. The preparation, characterization of the in vitro cytotoxicity and X-ray structures of several ferritin-metallodrug nanocomposites (mainly containing platinum-, ruthenium- and gold-based anticancer agents) are here reviewed. The molecular mechanisms of action of these Ft-metallodrug adducts are discussed and future directions in the field are outlined.

Arsenoplatin-1 Is a Dual Pharmacophore Anticancer Agent

Arsenoplatins are adducts of two chemically important anticancer drugs, cisplatin and arsenic trioxide, that have a Pt(II) bond to an As(III) hydroxide center. Screens of the NCI-60 human tumor cell lines reveal that arsenoplatin-1 (AP-1), [Pt(μ-NHC(CH3)O)2ClAs(OH)2], the first representative of this novel class of anticancer agents, displays a superior activity profile relative to the parent drugs As2O3 or cisplatin in a majority of cancer cell lines tested. These activity profiles are important because the success of arsenic trioxide in blood cancers (such as APL) has not been seen in solid tumors due to the rapid clearance of arsenous acid from the body. To understand the biological chemistry of these compounds, we evaluated interactions of AP-1 with the two important classes of biomolecules-proteins and DNA. The first structural studies of AP-1 bound to model proteins reveal that platinum(II) binds the Nε of His in a manner that preserves the Pt-As bond. We find that AP-1 readily enters cells and binds to DNA with an intact Pt-As bond (Pt:As ratio of 1). At longer incubation times, however, the Pt:As ratio in DNA samples increases, suggesting that the Pt-As bond breaks and releases the As(OH)2 moiety. We conclude that arsenoplatin-1 has the potential to deliver both Pt and As species to a variety of hematological and solid cancers.

Platinum(II) O,S Complexes Inhibit the Aggregation of Amyloid Model Systems

Platinum(II) complexes with different cinnamic acid derivatives as ligands were investigated for their ability to inhibit the aggregation process of amyloid systems derived from Aβ, Yeast Prion Protein Sup35p and the C-terminal domain of nucleophosmin 1. Thioflavin T binding assays and circular dichroism data indicate that these compounds strongly inhibit the aggregation of investigated peptides exhibiting IC₅₀ values in the micromolar range. MS analysis confirms the formation of adducts between peptides and Pt(II) complexes that are also able to reduce amyloid cytotoxicity in human SH-SY5Y neuroblastoma cells. Overall data suggests that bidentate ligands based on β-hydroxy dithiocinnamic esters can be used to develop platinum or platinoid compounds with anti-amyloid aggregation properties.

Encapsulation of the Dinuclear Trithiolato-Bridged Arene Ruthenium Complex Diruthenium-1 in an Apoferritin Nanocage: Structure and Cytotoxicity

The effects of encapsulating the cytotoxic dinuclear trithiolato-bridged arene ruthenium complex [(η⁶ -p-MeC₆ H₄ iPr)₂ Ru₂ (μ₂ -S-p-C₆ H₄ tBu)₃ ]Cl (DiRu-1) within the apoferritin (AFt) nanocage were investigated. The DiRu-1-AFt nanocarrier was characterized by UV/Vis spectroscopy, ICP-MS, CD and X-ray crystallography. In contrast to previously reported Au- and Pt-based drug-loaded AFt carriers, we found no evidence of direct interactions between DiRu-1 and AFt. DiRu-1-AFt is cytotoxic toward immortalized murine BALB/c-3T3 fibroblasts transformed with SV40 virus (SVT2) and human epidermoid carcinoma A431 malignant cells, and exhibits moderate selectivity for these cancer cells over normal BALB/c-3T3 cells. DiRu-1-AFt triggers the production of reactive oxygen species, depolarization of mitochondrial membrane potential, and induces cell death via p53-mediated apoptosis. Comparison between our data and previous results suggests that the presence of specific interactions between a metal-based drug and AFt within the protein cage is not essential for drug encapsulation.

Protein-mediated disproportionation of Au(i): insights from the structures of adducts of Au(iii) compounds bearingN,N-pyridylbenzimidazole derivatives with lysozyme

Structural data of protein/gold adducts suggest protein-mediated reduction of Au(iii) into Au(i) and disproportionation of Au(i) into Au(iii) and Au(0).

A highly efficient and selective antitumor agent based on a glucoconjugated carbene platinum(ii) complex

A Pt(ii) complex with a glucosylated carbene shows very high in vitro cytotoxicity and selectivity toward malignant cells.

Preparation, structure, cytotoxicity and mechanism of action of ferritin-Pt(II) terpyridine compound nanocomposites

AIM

A Pt(II)-terpyridine compound, bearing two piperidine substituents at positions 2 and 2' of the terpyridine ligand (1), is highly cytotoxic and shows a mechanism of action distinct from cisplatin. 1 has been incorporated within the ferritin nanocage (AFt).

MATERIALS & METHODS

Spectroscopic and crystallographic data of the Pt(II)-AFt nanocomposite have been collected and in vitro anticancer activity has been explored using cancer cells.

RESULTS

Pt(II)-containing fragments bind His49, His114 and His132. Pt(II)-AFt nanocomposite is less cytotoxic than 1, but it is more toxic than cisplatin at high concentrations. The Pt(II)-AFt nanocomposite triggers necrosis in cancer cells, as free 1 does.

CONCLUSION

Pt(II)-AFt nanocomposites are promising vehicles to deliver Pt-based drugs to cancer cells.

The NAMI A - human ferritin system: a biophysical characterization

The reaction of the antimetastatic ruthenium(iii) drug NAMI A with human H-chain ferritin (HuHf) was investigated through a variety of biophysical methods. We observed that the addition of HuHf to NAMI A solutions significantly increases the rate of spontaneous NAMI A hydrolysis suggesting the occurrence of a direct metallodrug-protein interaction. The resulting hydrolyzed Ru species binds the protein mostly forming a relatively tight 1 : 1 ruthenium/ferritin (subunit) adduct that was then separated and characterized. Notably, this adduct shows a characteristic CD spectrum in the visible region, which is diagnostic of the existence of at least one protein bound ruthenium center. The crystal structure of this NAMI A/HuHf adduct was subsequently solved at 1.58 Å resolution; clear evidence is given for the selective binding of a single Ru ion to His105 of each subunit with concomitant release of all other original Ru ligands in agreement with previous observations. We also noted that NAMI A produces a partial inhibition of HuHf ferroxidase activity. The implications of the above results are discussed.

Ferritin nanocages loaded with gold ions induce oxidative stress and apoptosis in MCF-7 human breast cancer cells

Two anticancer gold(iii) compounds, Au2phen and Auoxo4, were encapsulated within a ferritin nanocage. The gold-compound loaded proteins were characterized by UV-Vis spectroscopy, inductively coupled plasma mass spectrometry and circular dichroism. X-ray crystallography shows that the compounds degrade upon encapsulation and gold(i) ions bind Ft within the cage, close to the side chains of Cys126. The gold-encapsulated nanocarriers are cytotoxic to human cancer cells. Au(i)-loaded Ft, obtained upon the encapsulation of Au2phen within the cage, induces oxidative stress activation, which finally leads to apoptosis in MCF-7 cells.

Principles and methods used to grow and optimize crystals of protein-metallodrug adducts, to determine metal binding sites and to assign metal ligands

The characterization of the interactions between biological macromolecules (proteins and nucleic acids) and metal-based drugs is a fundamental prerequisite for understanding their mechanisms of action. X-ray crystallography enables the structural analysis of such complexes with atomic level detail. However, this approach requires the preparation of highly diffracting single crystals, the measurement of diffraction patterns and the structural analysis and interpretation of macromolecule-metal interactions from electron density maps. In this review, we describe principles and methods used to grow and optimize crystals of protein-metallodrug adducts, to determine metal binding sites and to assign and validate metal ligands. Examples from the literature and experience in our own laboratory are provided and key challenges are described, notably crystallization and molecular model refinement against the X-ray diffraction data.

Caged noble metals: Encapsulation of a cytotoxic platinum(II)-gold(I) compound within the ferritin nanocage

The encapsulation of Pt and Au-based anticancer agents within a protein cage is a promising way to enhance the selectivity of these potential drugs. Here a cytotoxic organometallic compound containing platinum(II) and gold(I) has been encapsulated within a ferritin nanocage (AFt). Inductively plasma coupled mass spectrometry data, collected to evaluate the amount of Pt and Au within the cage, indicate disruption of the starting heterobimetallic complex upon encapsulation within the nanocage. The drug-loaded protein (Pt(II)/Au(I)-AFt) has been characterized by UV-Vis spectroscopy, circular dichroism and X-ray diffraction analysis. Data indicate that the protein maintains its fold upon encapsulation of the metallodrug and that Au(I) and Pt(II)-containing fragments are encapsulated within the AFt cage, with Au(I) ion that binds the side chain of Cys126 and Pt(II) in the bulk, respectively. The in vitro cytotoxicity of Pt(II)Au(I)-AFt, as well as that of the free heterobimetallic complex, has been comparatively evaluated on human cervix and breast cancer cells and against cardiomyoblasts and keratinocytes non-tumorigenic cells. Our data demonstrate that it is possible to obtain a protein nanocarrier containing both Pt and Au atoms starting from a bimetallic compound, opening the way for the design and development of new potential drugs based on protein nanocarriers.

Gold-based drug encapsulation within a ferritin nanocage: X-ray structure and biological evaluation as a potential anticancer agent of the Auoxo3-loaded protein

Auoxo3, a cytotoxic gold(iii) compound, was encapsulated within a ferritin nanocage. Inductively coupled plasma mass spectrometry, circular dichroism, UV-Vis absorption spectroscopy and X-ray crystallography confirm the potential-drug encapsulation. The structure shows that naked Au(i) ions bind to the side chains of Cys48, His49, His114, His114 and Cys126, Cys126, His132, His147. The gold-encapsulated nanocarrier has a cytotoxic effect on different aggressive human cancer cells, whereas it is significantly less cytotoxic for non-tumorigenic cells.