Biomedical subjects

Silvia Schenone

Publications and source records attributed to Silvia Schenone.

At least 19 recordsLinked to original sources

PubMed2007

Pyrazolo-pyrimidine-derived c-Src inhibitor reduces angiogenesis and survival of squamous carcinoma cells by suppressing vascular endothelial growth factor production and signaling.

Src tyrosine kinase family cooperates with activated growth factor receptors to regulate growth, invasion and metastasis. The authors examined the influence of a novel c-Src inhibitor, 1l, derived from 4-amino-substituted-pyrazolo-pyrimidines, on tumor angiogenesis and on the angiogenic output of squamous carcinoma cells, A431 and SCC-4. The effect of 1l was assessed on growth and microvessel density in A431 tumors and its effect compared with the established c-Src inhibitor PP-1. The effects of c-Src inhibition were investigated on vascular endothelial growth factor (VEGF) expression and activity in tumor cells grown in vivo and in vitro, as well as on VEGF mediated signaling and on endothelial cell functions. Nanomolar concentrations of 1l decreased tumor volume promoted by A431 implanted in nude mice, without affecting in vitro cell tumor survival. This effect was related to 1l inhibition of VEGF production, and secondary to an effect on tumor microvessel density. The rabbit cornea assay confirmed that 1l markedly decreased neovessel growth induced by VEGF. In cultured endothelial cells, 1l inhibited the VEGF-induced phosphorylation on tyr416 of c-Src, resulting in a reduced cell proliferation and invasion. Consistently, 1l dowregulated endothelial nitric oxide synthase, MAPK-extracellular receptor kinase 1-2 (ERK1-2) activity and matrix metalloproteinases (MMP-2/MMP-9), while the tissue inhibitors of metalloproteinases (TIMP2/TIMP-1) were upregulated. These results demonstrate that nM concentrations of c-Src kinase inhibitors (1l and PP-1), by reducing the production of VEGF released by tumor cell and its endothelial cell responses, have a highly selective antiangiogenesis effect, which might be useful in combination therapies.

Animals↗

PubMed2006

Pyrazolo[3,4-d]pyrimidines c-Src inhibitors reduce epidermal growth factor-induced migration in prostate cancer cells.

During its biological progression, prostate cancer frequently develops dependence on growth factor receptors and their downstream signalling messengers, including c-Src. Evidence for this supports the choice of c-Src as a therapeutic target in the prevention of tumour spreading. Two new pyrazolo[3,4-d]pyrimidines c-Src inhibitors, SI35 and SI40, were used to investigate the role of c-Src in the control of the aggressive phenotype of prostate carcinoma cell line, PC3. SI molecules reduced the proliferation of PC3 cells in a time- and dose-dependent manner, with an IC50 of approximately 50 microM. PC3 cells responded to the presence of epidermal growth factor (EGF) by increasing their migratory ability, and this effect was strongly reduced by the addition of SI at concentrations less than IC50. Further observations demonstrated that SI molecules modulated cell morphology and their adhesive capacity on different physiological substrates. The action of SI molecules appeared to involve, in parallel with c-Src inhibition, the down-modulation of the active forms of paxillin and extracellular signal-regulated kinase (ERK). Our data suggest a promising role for pyrazolo[3,4-d]pyrimidines c-Src inhibitors in the control of a highly invasive tumour phenotype.

Cell Adhesion↗

PubMed2006

A combination of docking/dynamics simulations and pharmacophoric modeling to discover new dual c-Src/Abl kinase inhibitors.

A computational protocol was applied to identify molecular scaffolds untested toward the c-Src tyrosine kinase. A combination of docking and dynamics calculations allowed us to build three-dimensional models of the complexes between Src and several of its known inhibitors. Interactions most contributing to activity of the inhibitors, in terms of hydrogen bonds and hydrophobic contacts, were codified into pharmacophoric models that were in turn applied to perform a search of commercially available compounds within the Asinex database. As a result, we identified 1,3,4-thiadiazoles and pyrazolydine-3,5-diones showing inhibitory activity in the submicromolar range in a cell-free assay toward Src. Moreover, since several of the compounds used to generate pharmacophores were also known as Abl inhibitors, we tested the identified hits toward Abl tyrosine kinase, finding activity in the submicromolar range. Such biological data suggested that the computational protocol is an efficient tool for identifying new hits toward both Src and Abl.

CSK Tyrosine-Protein Kinase↗

PubMed2006

Pyrazolo[3,4-d]pyrimidines as potent antiproliferative and proapoptotic agents toward A431 and 8701-BC cells in culture via inhibition of c-Src phosphorylation.

We report here the synthesis of new pyrazolo[3,4-d]pyrimidine derivatives along with their biological properties as inhibitors of isolated Src and cell line proliferation (A431 and 8701-BC cells). Such compounds block the growth of cancer cells by interfering with the phosphorylation of Src, and they act as proapoptotic agents through the inhibition of the anti apoptotic gene BCL2. Several of them were found to be more active than the reference compound (1-(tert-butyl)-3-(4-chlorophenyl)-4-aminopyrazolo[3,4-d]pyrimidine, PP2) in inhibiting cell proliferation and in inducing apoptosis, and as active as PP2 in the inhibition of the phosphorylation of isolated Src. Moreover, molecular modeling simulations have been performed to hypothesize the way, at the molecular level, by which the inhibitors were able to act as antiproliferative agents.

Antineoplastic Agents↗

PubMed2005

Synthesis of new piperazine-pyridazinone derivatives and their binding affinity toward alpha1-, alpha2-adrenergic and 5-HT1A serotoninergic receptors.

We report the design and synthesis of a new class of piperazine-pyridazinone analogues. The arylpiperazine moiety, the length of the spacer, and the terminal molecular fragment were varied to evaluate their influence in determining the affinity of the new compounds toward the alpha1-adrenergic receptor (alpha1-AR), alpha2-adrenergic receptor (alpha2-AR), and the 5-HT1A serotoninergic receptor (5-HT1AR). Biological data showed that most of the compounds have an alpha1-AR affinity in the nanomolar or subnanomolar range, while affinity toward the other two receptors was lower in most cases. However, several of the tested compounds also showed very good (in the nanomolar range) or moderate affinity toward the 5-HT1AR subtype.

Animals↗

PubMed2005

New 1,3,4-thiadiazole derivatives endowed with analgesic and anti-inflammatory activities.

Two series of N-[5-oxo-4-(arylsulfonyl)-4,5-dihydro-1,3,4-thiadiazol-2-yl]-amides were synthesized and tested in vivo for their analgesic and anti-inflammatory activities. All the new compounds possess good antalgic action in the acetic acid writhing test and some terms of the series showed also fair anti-inflammatory activity in the carrageenan rat paw edema test. Ulcerogenic and irritative action on the gastrointestinal mucose, in comparison with indomethacin is low.

Amides↗

PubMed2005

Synthesis and 3D QSAR of new pyrazolo[3,4-b]pyridines: potent and selective inhibitors of A1 adenosine receptors.

A number of 4-aminopyrazolo[3,4-b]pyridines 5-carboxylic acid esters (2-8) were synthesized and evaluated for their binding affinity at the A1, A2A, and A3 adenosine receptors (AR), in bovine cortical membranes, as well as for their affinity toward human A1AR (hA1AR). Some of the new compounds were characterized by a high affinity and selectivity toward the A1 receptor subtype, showing a significant improvement in comparison with other pyrazolo-pyridines previously reported in the literature. In particular the methyl ester 2h as well as the isopropyl ester 5h, both of them bearing a p-methoxyphenylethylamino side chain at the position 4, presented Ki values of 6 and 7 nM, respectively. To rationalize the relationships between structure and affinity of the novel compounds, a 3D QSAR model was also generated starting from compounds belonging to different classes of known A1AR antagonists.

Adenosine A1 Receptor Antagonists↗

PubMed2005

Affinity prediction on A1 adenosine receptor agonists: the chemometric approach.

In this paper, we are presenting a quantitative-structure-activity relationship (QSAR) study performed on 21 selective A(1) adenosine receptor agonists plus the endogenous substrate, adenosine, so as to identify those predictors which play a key role in describing the binding of the ligand with the A(1) receptor. A large number of molecular descriptors plus a calculated receptor-agonist binding energy and atomic charges were taken into account to derive different QSAR models, using different regression techniques. The results obtained both with linear and nonlinear approaches converge to the selection of the same informative parameters, highlighting the correlation of these descriptors with the biological Response. The evaluation 'a priori' of these predictors could therefore represent a useful tool in the screening of large libraries of compounds and in the rational design of new selective agonists.

Adenosine↗

PubMed2005

Synthesis, antiplatelet and antithrombotic activities of new 2-substituted benzopyrano[4,3-d]pyrimidin-4-cycloamines and 4-amino/cycloamino-benzopyrano[4,3-d]pyrimidin-5-ones.

Atherothrombotic coronary artery disease, associated with deep vein thrombosis, is one of the most common causes of death worldwide. Recently, antiplatelet combination therapy using agents with different mechanisms of action, such as aspirin, dipyridamole, and thienopyridines, seems to be an attractive preventive approach. Moreover, several large, randomized clinical trials support combination therapy with aspirin plus warfarin in high-risk patients with atherosclerotic heart disease. Our research on the benzopyrano[4,3-d]pyrimidine system gave rise to the synthesis of a large number of compounds endowed with in vitro anti-aggregating activity. Several SAR considerations suggest that the benzopyranopyrimidine system is an appropriate scaffold to obtain molecules that are able to act simultaneously in different pathways of aggregation. Now, we report the synthesis of new 2-substituted benzopyrano[4,3-d]pyrimidin-4-cycloamines and 4-amino/cycloamino-benzopyrano[4,3-d]pyrimidin-5-ones and the results of the pharmacological study on haemostasis. Some tested compounds showed a large-spectrum antiplatelet activity in vitro, and are more potent than aspirin as antithrombotics in vivo but, at variance with aspirin, they do not increase bleeding. This paper describes novel antithrombotic compounds with an interesting pharmacological profile and a potentially attractive benefit/risk ratio, with their mechanism of action generally, but not exclusively, dependent on antiplatelet activity, deserving further investigations.

Animals↗

PubMed2005

Structure-based design, parallel synthesis, structure-activity relationship, and molecular modeling studies of thiocarbamates, new potent non-nucleoside HIV-1 reverse transcriptase inhibitor isosteres of phenethylthiazolylthiourea derivatives.

In this paper we describe our structure-based ligand design, synthetic strategy, and structure-activity relationship (SAR) studies that led to the identification of thiocarbamates (TCs), a novel class of non-nucleoside reverse transcriptase inhibitors (NNRTIs), isosteres of phenethylthiazolylthiourea (PETT) derivatives. Assuming as a lead compound O-[2-(phthalimido)ethyl]phenylthiocarbamate 12, one of the precursors of the previously described acylthiocarbamates (Ranise, A.; et al. J. Med. Chem. 2003, 46, 768-781), two targeted solution-phase TC libraries were prepared by parallel synthesis. The lead optimization strategy led to para-substituted TCs 31, 33, 34, 39, 40, 41, 44, 45, and 50, which were active against wild-type HIV-1 in MT-4-based assays at nanomolar concentrations (EC50 range: 0.04-0.01 microM). The most potent congener 50 (EC50 = 0.01 microM) bears a methyl group at position 4 of the phthalimide moiety and a nitro group at the para position of the N-phenyl ring. Most of the TCs showed good selectivity indices, since no cytotoxic effect was detected at concentrations as high as 100 microM. TCs 31, 37, 39, 40, and 44 significantly reduced the multiplication of the Y181C mutant, but they were inactive against K103R and K103N + Y181C mutants. Nevertheless, the fold increase in resistance of 41 was not greater than that of efavirenz against the K103R mutant in enzyme assays. The docking model predictions were consistent with in vitro biological assays of the anti-HIV-1 activity of the TCs and related compounds synthesized.

Anti-HIV Agents↗

PubMed2005

New pyrazolo[3,4-b]pyridones as selective A(1) adenosine receptor antagonists: synthesis, biological evaluation and molecular modelling studies.

A series of ethyl 4-amino-1-(2-chloro-2-phenylethyl)-6-oxo-6,7-dihydro-1H-pyrazolo[3,4-b]pyridine-5-carboxylates () has been synthesized as potential A(1) adenosine receptor (A(1) AR) ligands. Binding affinities of the new compounds were determined for adenosine A(1), A(2A) and A(3) receptors. Compounds and showed good affinity (K(i)= 299 nM and 517 nM, respectively) and selectivity towards A(1) AR, whereas showed good affinity for A(2A) AR (K(i)= 290 nM), higher than towards A(1) AR (K(i)= 1000 nM). The only arylamino derivative of the series displayed high affinity (K(i)= 4.6 nM) and selectivity for A(3) AR. Molecular modelling and 3D-QSAR (CoMFA) studies carried out on the most active compounds gave further support to the pharmacological results.

Models, Molecular↗

PubMed2004

Synthesis, antimicrobial activity and molecular modeling studies of halogenated 4-[1H-imidazol-1-yl(phenyl)methyl]-1,5-diphenyl-1H-pyrazoles.

During the course of our studies in the azole antifungals area, we synthesized a number of 1,5-disubstituted 4-[1H-imidazol-1-yl(phenyl)methyl]-1H-pyrazoles, analogues of bifonazole. 1,5-Diphenyl-1H-pyrazole 3 showed weak antimycotic and antibacterial activities in vitro against Candida albicans, Cryptococcus neoformans and Staphylococcus aureus. In order to increase these properties, given that the halo substitution was found to be capable of enhancing antifungal effects, we prepared a series of fluoro and chloro derivatives of 3. The microbiological evaluation carried out on newly synthesized compounds included in vitro assays for antifungal, antibacterial and antimycobacterial activities. Among the tested compounds, some dichloro and trichloro-derivatives showed interesting antimicrobial properties. In particular, compounds 10j,k,l produced inhibitory effects against pathogen representatives of yeast (C. albicans, C. neoformans) and Gram positive bacteria (S. aureus) similar or superior to those of bifonazole. In addition, their activity against Mycobacterium tuberculosis was superior to that of clotrimazole and econazole, which were used as reference drugs. The replacement, in these compounds, of chlorine with fluorine atoms led to inactive derivatives. Docking studies were carried out on the most active compounds, in order to rationalize the pharmacological results.

Anti-Bacterial Agents↗

PubMed2004

Pyrazolo[3,4-d]pyrimidines endowed with antiproliferative activity on ductal infiltrating carcinoma cells.

Novel 1,4,6-trisubstituted pyrazolo[3,4-d]pyrimidines are reported with preliminary in vitro activity data indicating that several of them are potent inhibitors (better than the reference compound) of Src phosphorylation of the breast cancer cells 8701-BC, known to overexpress Src. The ability of such compounds to significantly reduce 8701-BC cell proliferation suggests that this scaffold could be a promising lead for the development of antitumoral agents able to block Src phosphorylation of breast cancer cells.

Antineoplastic Agents↗

PubMed2004

Synthesis and pharmacological evaluation of 5H-[1]benzopyrano[4,3-d]pyrimidines effective as antiplatelet/analgesic agents.

Synthesis and pharmacological screening of new 2-methylthio/2-methanesulfonyl/2-methoxy-5H-[1]benzopyrano[4,3-d]pyrimidines were planned in order to study the effects of the 5-substitution with alkoxy/phenoxy/alkylthio and phenylthio groups both on in vitro antiplatelet and in vivo antinociceptive activities. Antiplatelet activity was assessed in vitro against ADP, Arachidonic acid and U46619 induced aggregation, in rabbit plasma. Anti-inflammatory, analgesic and antipyretic activities were tested in rat paw edema, mouse writhing test and LPS induced rat fever, respectively. Amongst test compounds, 2-methylthio derivatives displayed an ASA-like antiplatelet activity whereas 2-methoxy and, particularly, 2-methanesulfonyl derivatives showed a broad spectrum of antiplatelet action, inhibiting both the ADP- and the AA- and U46619-induced aggregation. With regard to the in vivo pharmacological activities, mainly the 2-methoxy derivatives showed a significant analgesic effect comparable to that of indomethacin. SAR considerations, also in comparison with a number of previously described compounds, were performed.

Analgesia↗

PubMed2004

Synthesis of 1-(2-chloro-2-phenylethyl)-6-methylthio-1H-pyrazolo[3,4-d]pyrimidines 4-amino substituted and their biological evaluation.

A new series of 4-amino-6-methylthio-1H-pyrazolo[3,4-d]pyrimidines (2a-m) bearing the 2-chloro-2-phenylethyl chain at the N1 position, has been synthesized. The affinity of these compounds for A1 adenosine receptor (A1AR) was measured. The compounds showed poor affinity. A more interesting result was obtained by 2a, 2d, 2g, which demonstrated inhibitory activity on cell proliferation of the A-431 cell line stimulated by epithelial growth factor (EGF) and on EGF receptor tyrosine kinase (EGFR-TK) phosphorylation.

Adenosine A1 Receptor Antagonists↗

PubMed2004

Antiproliferative activity of new 1-aryl-4-amino-1H-pyrazolo[3,4-d]pyrimidine derivatives toward the human epidermoid carcinoma A431 cell line.

Synthesis and biological evaluation of a new class of 1-aryl-4-amino-1H-pyrazolo[3,4-d]pyrimidine derivatives are reported. A preliminary cellular assay system using the tumor cell line A431 responding to epidermal growth factor (EGF) for its growth, shows that the new compounds are potent inhibitors of cell growth. The inhibition of tumor cell proliferation is not associated with blockage of EGF receptor (EGFR), but substantially due to the interference with the signalling pathway at the level of Src tyrosine kinase and at the level of the downstream effector signal mitogen activated protein kinases (MAPKs), ERK1-2.

Antineoplastic Agents↗

PubMed2004

Synthesis and biological evaluation of neutrophilic inflammation inhibitors.

In several non-infectious human diseases, such as ulcerous colitis, rheumatoid arthritis, chronic obstructive pulmonary disease (COPD), the extravasal recruitment of neutrophils plays a crucial role in the development of tissue damage, which, when persistent, can lead to the irreversible organ dysfunction. The neutrophil activation is controlled by a number of intracellular pathways, particularly by a cAMP-dependent protein kinase A (PKA) which also acts on phosphodiesterase IV (PDE4) gene stimulating the synthesis of this enzyme, able to transform cAMP to inactive AMP. PDE4 inhibitors enhance intracellular cAMP and decrease inflammatory cell activation. Several 3-cyclopentyloxy-4-methoxybenzaldehyde and 3-cyclopentyloxy-4-methoxybenzoic acid derivatives were synthesized and studied by us to evaluate their ability to inhibit the superoxide anion production in human neutrophils. These compounds were found able to inhibit the neutrophil activation and some of them increased the cAMP level on tumor necrosis factor-alpha-stimulated neutrophils. Moreover, they also inhibited selectively the human PDE4 enzyme, although they are less potent than the reference compound Rolipram. We report here synthesis, biological studies and some SAR considerations concerning the above mentioned compounds.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed2003

Synthesis and antiproliferative activity of basic thioanalogues of merbarone.

Three series of 5-substituted 1,3-diphenyl-6-(omega-dialkyl- and omega-cyclo-aminoalkyl)thio-2-thiobarbiturates (11-13) were synthesized as polysubstituted thioanalogues of merbarone, a topoisomerase II inhibitor acting on the catalytic site. To better understand pharmacophore requirements, a forth series of conformationally constrained analogues 14 was also prepared. Derivatives 11b,e, 14b,e,h,i,j were active in the low micromolar concentration range (IC(50): 3.3-4.3 microM), whereas compounds 11a,c,d,f,h,j and 13a,b,d,g,j and 14a,d,f showed IC(50) values between 10 and 15.5 microM. In contrast, compounds 12a-c,g-j, 13e,f,h and 14k were inactive. Cytotoxicity data provided from N.C.I. on selected compounds provided evidence that 11b,d, 13d,g and 14b,d,f,h,i,j were endowed with potent antiproliferative activity against leukemia and prostate cell lines (GI(50) up to 0.01 microM). In general, bicyclic derivatives 14 were up to 10-fold more potent than monocyclic counterparts against solid tumor-derived cell lines. SAR studies indicated that, in general, a certain tolerability in length of the alkyl side chains and in shape of distal amines is allowed in the four series, but in the monocyclic derivatives (11-13) antiproliferative activity was strongly affected by the nature of the 5-substituents (COOC(2)H(5)>COCH(3)>>C(6)H(5)). Compounds 11b and 14b were also evaluated against KB cell subclones expressing altered levels of topoisomerases or the multidrug resistance phenotype (MDR). In both cases the above compounds showed a decrease in potency. In enzyme assays, 11b and 14b turned out to be inhibitors of topoisonerase II as merbaron.

Antineoplastic Agents↗