Cell-specific pattern of berberine pleiotropic effects on different human cell lines.

The natural alkaloid berberine has several pharmacological properties and recently received attention as a potential anticancer agent. In this work, we investigated the molecular mechanisms underlying the anti-tumor effect of berberine on glioblastoma U343 and pancreatic carcinoma MIA PaCa-2 cells. Human dermal fibroblasts (HDF) were used as non-cancer cells.

Astacin gene family of metalloproteinases in planarians: Structural organization and tissue distribution.

Planarian flatworms possess extraordinary regenerative capability and body plasticity, which rely on a composite population of stem cells, the neoblasts. Despite impressive advances have been recently achieved in the knowledge of neoblast biology, few is still known about factors that are released by differentiated tissues and influence the neoblast fate. Extracellular matrix (ECM) is a fundamental component of the stem cell niche and its remodeling affects stem cell fate.

The natural compound sanguinarine perturbs the regenerative capabilities of planarians.

The natural alkaloid sanguinarine has remarkable therapeutic properties and has been used for centuries as a folk remedy. This compound exhibits interesting anticancer properties and is currently receiving attention as a potential chemotherapeutic agent. Nevertheless, limited information exists regarding its safety for developing organisms.

In vitro studies of antifibrotic and cytoprotective effects elicited by proto-berberine alkaloids in human dermal fibroblasts.

Background: The pathogenic mechanisms of skin fibrosis are still not completely understood, unlike the profibrotic role played by inflammatory cytokines and transforming growth factor-β1 (TGF-β1). Few antifibrotic drugs are available. Nevertheless, folk medicine suggests numerous treatments of fibrotic conditions.

Rare disease registries classification and characterization: a data mining approach.

Background: The European Commission and Patients Organizations identify rare disease registries (RDRs) as strategic instruments to develop research and improve knowledge in the field of rare diseases. Interoperability between RDRs is needed for research activities, validation of therapeutic treatments, and public health actions. Sharing and comparing information requires a uniform and standardized way of data collection, so levels of interconnection between RDRs with similar aims and/or nature of data should be identified.

Enzyme kinetics studies on 29-kDa human liver cathepsin L.

Enzyme kinetics studies reported in the literature showed that human liver Cathepsin L is active only at lysosomal acidic pH values, while biochemical studies in living cells showed that the enzyme works even at neutral pH values (in a condition compatible with the extracellular compartment). Such an apparent ambiguity highlighted the need of analysing in depth the kinetics of ~29-kDa Cathepsin L, which is the form commonly used in experiments. The stability and catalytic activity of this enzyme were investigated at different pH values, reducing and non-reducing environments, presence of copper, iron and zinc ions, and presence of the natural modulator/inhibitor cystatin B.

Berberine exposure triggers developmental effects on planarian regeneration.

The mechanisms of action underlying the pharmacological properties of the natural alkaloid berberine still need investigation. Planarian regeneration is instrumental in deciphering developmental responses following drug exposure. Here we report the effects of berberine on regeneration in the planarian Dugesia japonica.

Combining structure- and ligand-based approaches for studies of interactions between different conformations of the hERG K+ channel pore and known ligands.

Drug-induced insurgence of cardiotoxic effects signaled by the prolongation of the QT interval in the electrocardiogram, has the potential to evolve into a characteristic arrhythmic event named Torsade de Pointes (TdP). Although several different mechanisms can theoretically lead to prolonged QT interval, most of drugs showing this side effect, prolong the cardiac repolarization time through the inhibition of the rapid component of the delayed repolarizing current (IKr) which in humans is carried by a K(+) channel protein encoded by hERG. In this study, four 3D-models, representing different conformational states of hERG K(+) channel, were built by a homology-based technique.

N-[9-(ortho-fluorobenzyl)-2-phenyl-8-azapurin-6-yl]-amides as potent and selective ligands for A₁ adenosine receptors.

A series of N-[9-(ortho-fluorobenzyl)-2-phenyl-8-azapurin-6-yl]-amides were synthesized and tested for their affinity toward A₁, A2A , and A₃ adenosine receptor subtypes. Biological results demonstrated that the introduction of a fluorine atom at the ortho position of the 9-benzyl group generally enhanced affinity toward A₁ subtype and did not significantly affect A2A and A₃ affinity. Very interesting is the compound bearing a meta-fluorophenyl substituent on the carbonyl carbon of the amide group, which shows significantly high A₁/A2A-A₃ selectivity.

Planarians as a model to assess in vivo the role of matrix metalloproteinase genes during homeostasis and regeneration.

Matrix metalloproteinases (MMPs) are major executors of extracellular matrix remodeling and, consequently, play key roles in the response of cells to their microenvironment. The experimentally accessible stem cell population and the robust regenerative capabilities of planarians offer an ideal model to study how modulation of the proteolytic system in the extracellular environment affects cell behavior in vivo. Genome-wide identification of Schmidtea mediterranea MMPs reveals that planarians possess four mmp-like genes.

Development of classification models for identifying "true" P-glycoprotein (P-gp) inhibitors through inhibition, ATPase activation and monolayer efflux assays.

P-glycoprotein (P-gp) is an efflux pump involved in the protection of tissues of several organs by influencing xenobiotic disposition. P-gp plays a key role in multidrug resistance and in the progression of many neurodegenerative diseases. The development of new and more effective therapeutics targeting P-gp thus represents an intriguing challenge in drug discovery.

The in vivo effect of chelidonine on the stem cell system of planarians.

The presence of adult pluripotent stem cells and the amazing regenerative capabilities make planarian flatworms an extraordinary experimental model to assess in vivo the effects of substances of both natural and synthetic origin on stem cell dynamics. This study focuses on the effects of chelidonine, an alkaloid obtained from Chelidonium majus. The expression levels of molecular markers specific for stem or differentiated cells were compared in chelidonine-treated and control planarians.

Synthesis and biological activities of vitamin D-like inhibitors of CYP24 hydroxylase.

Selective inhibitors of CYP24A1 represent an important synthetic target in a search for novel vitamin D compounds of therapeutic value. In the present work, we show the synthesis and biological properties of two novel side chain modified 2-methylene-19-nor-1,25(OH)(2)D(3) analogs, the 22-imidazole-1-yl derivative 2 (VIMI) and the 25-N-cyclopropylamine compound 3 (CPA1), which were efficiently prepared in convergent syntheses utilizing the Lythgoe type Horner-Wittig olefination reaction. When tested in a cell-free assay, both compounds were found to be potent competitive inhibitors of CYP24A1, with the cyclopropylamine analog 3 exhibiting an 80-1 selective inhibition of CYP24A1 over CYP27B1.

Identification of selective ligands for human fibrin recognition using high-throughput docking.

The ultimate aim of this study is to identify new molecules that are able to recognize polymerized fibrin, which is the main component of a thrombus. These selective ligands can be exposed on the surface of particular nanoparticles used for the targeted delivery of fibrinolytic drugs. The targeted delivery of these drugs is expected to help to keep under control the severe side effects which can occur if the drugs are administered systemically.

Structure-activity relationships on purine and 2,3-dihydropurine derivatives as antitubercular agents: a data mining approach.

Nowadays, many people still fall victim to tuberculosis, the disease that has a worldwide spreading. Moreover, the problem of resistance to isoniazid and rifampin, the two most effective antitubercular drugs, is assuming an ever-growing importance. The need for new drugs active against Mycobacterium tuberculosis represents nowadays a quite relevant problem in medicinal chemistry.

Optimizing QSAR models for predicting ligand binding to the drug-metabolizing cytochrome P450 isoenzyme CYP2D6.

The cytochrome P450 isozyme CYP2D6 binds a large variety of drugs, oxidizing many of them, and plays a crucial role in establishing in vivo drug levels, especially in multidrug regimens. The current study aimed to develop reliable predictive models for estimating the CYP2D6 inhibition properties of drug candidates. Quantitative structure-activity relationship (QSAR) studies utilizing 51 known CYP2D6 inhibitors were carried out.

Three-dimensional models of the oligomeric human asialoglycoprotein receptor (ASGP-R).

The work presented here is aimed at suggesting plausible hypotheses for functional oligomeric forms of the human asialoglycoprotein receptor (ASGP-R), by applying a combination of different computational techniques. The functional ASGP-R is a hetero-oligomer, that comprises of several subunits of two different kinds (H1 and H2), which are highly homologous. Its stoichiometry is still unknown.

Quantitative structure-activity relationship models for predicting biological properties, developed by combining structure- and ligand-based approaches: an application to the human ether-a-go-go-related gene potassium channel inhibition.

A strategy for developing accurate quantitative structure-activity relationship models enabling predictions of biological properties, when suitable knowledge concerning both ligands and biological target is available, was tested on a data set where molecules are characterized by high structural diversity. Such a strategy was applied to human ether-a-go-go-related gene K(+) channel inhibition and consists of a combination of ligand- and structure-based approaches, which can be carried out whenever the three-dimensional structure of the target macromolecule is known or may be modeled with good accuracy. Molecular conformations of ligands were obtained by means of molecular docking, performed in a previously built theoretical model of the channel pore, so that descriptors depending upon the three-dimensional molecular structure were properly computed.

Development of QSAR models for predicting hepatocarcinogenic toxicity of chemicals.

A dataset comprising 55 chemicals with hepatocarcinogenic potency indices was collected from the Carcinogenic Potency Database with the aim of developing QSAR models enabling prediction of the above unwanted property for New Chemical Entities. The dataset was rationally split into training and test sets by means of a sphere-exclusion type algorithm. Among the many algorithms explored to search regression models, only a Support Vector Machine (SVM) method led to a QSAR model, which was proved to pass rigorous validation criteria, in accordance with the OECD guidelines.

Synthesis, biological assays and QSAR studies of N-(9-benzyl-2-phenyl-8-azapurin-6-yl)-amides as ligands for A1 adenosine receptors.

2-Phenyl-9-benzyl-8-azapurines, bearing at the 6 position an amido group interposed between the 8-azapurine moiety and an alkyl or a substituted phenyl group, have been synthesised and assayed as ligands for adenosine receptors. All the compounds show high affinity for the A(1) adenosine receptor, and many of them also show a good selectivity for A(1) with respect to A(2A) and A(3) adenosine receptors. Based on the quite rich library containing such compounds and relevant biological data, QSAR models, able to rationalise the results and to give a quantitative estimate of the observed trends were also developed.

Computational modeling and surface plasmon resonance analyses in the assessment of peptide ligands interacting with fibrin gamma(312-324) epitope.

Fibrin represents a suitable target for addressing delivery systems loaded by fibrinolytic drugs. Selective ligands capable to recognize fibrin could be used as targeting moieties for such systems. In this study the interactions between the gamma(312-324) epitope of human fibrin and peptidic ligands were analyzed by using experimental and computational methods.