Biomedical subjects

Mauro Niso

Publications and source records attributed to Mauro Niso.

8 recordsLinked to original sources

PubMed2006

Is the sigma2 receptor a histone binding protein?

Starting from the high affinity sigma(2) receptor ligand 2, (PB28), we synthesized amino derivative 4 and coupled it to an NHS-ester activated sepharose stationary phase column to elute a crude protein prepared by lysed human SK-N-SH neuroblastoma cells. We characterized the SDS-PAGE gel electrophoresis stained bands by MALDI-MS and LC-MS-MS analysis. The MASCOT MS-MS ion search program led to the identification of the protein components. The six eluted proteins had a molecular weight ranging from 13 kDa to 26 kDa and were human histone proteins. A human 40S ribosomal protein S3 (SwissProt accession number: P23396) was also identified as a comigrated band. The human histone proteins that were characterized were H3.3A histone (NCBI accession number: 51859376), H2B histone (NCBI accession number: 1568557), H2A.5 histone (NCBI accession number: 70686), H1 (NCBI accession number: 22770677), and H2.1 histone (SwissProt accession number: P16403). These results disclosed a dual hypothesis about the sigma(2) receptor, that is, that it is formed by histones or that the sigma(2) ligands also bind histone proteins.

1-Naphthylamine↗

PubMed2006

The sigma-2 receptor agonist PB28 inhibits calcium release from the endoplasmic reticulum of SK-N-SH neuroblastoma cells.

In this paper we demonstrate that PB28 abolishes the Ca2+ release through the inositol 1,4,5-trisphosphate (InsP3) receptors and ryanodine receptors in SK-N-SH cells. Sigma receptors are divided into the subtypes sigma-1 and sigma-2, which are expressed in tumor cell lines and characterized by distinct pharmacological profiles. The sigma-1 receptor has been recently cloned, whereas the sigma-2 receptor is less well characterized. The endogenous ligand(s) of both subtypes remain unclear. In isolated guinea pig ileum, PB28 inhibits the contraction induced by carbachol dose dependently and in a non-competitive manner. In SK-N-SH cells PB28 challenge does not affect the intracellular Ca2+ concentration but incubation with PB28 for 45 min abolishes the cytosolic Ca2+ increases evoked by carbachol or histamine. This effect, not sensitive to cycloheximide, is caused by direct inhibition of the InsP3 receptors, since PB28 abolishes the response elicited by InsP3 administration in permeabilized SK-N-SH cells. Finally, incubation for 45 min with PB28 also abolishes the cytosolic Ca2+ increase evoked by caffeine.

Animals↗

PubMed2006

Design, synthesis, and binding affinities of potential positron emission tomography (PET) ligands for visualization of brain dopamine D3 receptors.

We here report the synthesis of compounds structurally related to the high-affinity dopamine D(3) receptor ligand N-[4-[4-(2,3-dichlorophenyl)piperazin-1-yl]butyl]-7-methoxy-2-benzofurancarboxamide (1). All compounds were specifically designed as potential PET radioligands for brain D(3) receptors visualization, having lipophilicity within a range for high brain uptake and weak nonspecific binding (2 < ClogP < 3.5) and bearing a methoxy substituent for easy access to labeling with the positron emitter isotope (11)C. N-[4-[4-(5-methoxy-2-benzisoxazolyl)piperazin-1-yl]butyl]-4-(4-morpholinyl)benzamide (22), N-[4-[4-(5-methoxy-2-benzisoxazolyl)piperazin-1-yl]butyl]-4-(1H-imidazol-1-yl)benzamide (23), and N-[4-[4-(5-methoxy-2-benzisoxazolyl)piperazin-1-yl]butyl]-5-(2-furanyl)-1H-pyrazole-3-carboxamide (24) displayed good D(3) receptor affinities (K(i) values 38.0, 22.6, and 21.3 nM, respectively) and were selective over D(2) receptor. Moreover, compounds 22-24 were able to permeate the Caco-2 cell monolayer, differently from compound 1. Although the goal to identify potential PET radioligands with subnanomolar affinities for D(3) receptor was not achieved, the proposed strategy could be a starting point for future developments.

Animals↗

PubMed2006

Cyclohexylpiperazine derivative PB28, a sigma2 agonist and sigma1 antagonist receptor, inhibits cell growth, modulates P-glycoprotein, and synergizes with anthracyclines in breast cancer.

sigma Ligands have recently been shown to have cytotoxic activity, to induce ceramide-dependent/caspase-independent apoptosis, and to down-regulate P-glycoprotein (P-gp) mRNA levels in some mouse and human models. In this study, we verified whether a mixed sigma(2) agonist/sigma(1) antagonist, PB28, was able to have antitumor activity and to enhance anthracycline efficacy in two human breast cancer cell lines, MCF7 and MCF7 ADR, both characterized by significant sigma(2) receptor expression, by high and low sigma(1) receptor expression, and low and high P-gp expression, respectively. In both cell lines, PB28 showed high sigma(2) receptor affinity and low sigma(1) receptor affinity; furthermore, it inhibited cell growth with a clear effect at 48 hours (IC(50) in nanomolar range), a consistent time exposure-independent increase of G(0)-G(1)-phase fraction (of approximately 20% of both cell lines) and caspase-independent apoptosis (15% increased after 1-day drug exposure). PB28 also reduced P-gp expression in a concentration- and time-dependent manner ( approximately 60% in MCF7 and 90% in MCF7 ADR). We showed also a strong synergism between PB28 and doxorubicin by adopting either simultaneous or sequential schedules of the two drugs. We suggest that this synergism could depend on PB28-induced increase of intracellular accumulation of doxorubicin ( approximately 50% in MCF7 and 75% in MCF7 ADR by flow cytometry analysis). In conclusion, we suggest that the sigma(2) agonist PB28 could be an interesting antitumor agent either in monotherapy or in combination with conventional drugs.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2005

Correlation between sigma2 receptor protein expression and histopathologic grade in human bladder cancer.

Sigma2 (sigma2) receptor proteins are overexpressed in several tissues and tumour cell lines. Although the biomolecular mechanism of this overexpression must be elucidated, sigma2 receptor was considered a potential biomarker for monitoring solid tumour proliferation. In this study, we verified first sigma2 receptor overexpression by saturation analysis with radioligand in six human bladder cancer specimens, then if a possible correlation could be established between sigma2 overexpression and tumour tissue stage and grade. The results displayed that sigma2 receptor protein was normally expressed in human bladder and overexpressed in the case of high-grade transitional cell carcinomas. Moreover, these receptors were undetected in a low-grade squamous cell carcinoma and in a very rare form of anaplastic, large cells plasmacytoid cancer.

Aged↗

PubMed2005

Distribution of sigma receptors in EMT-6 cells: preliminary biological evaluation of PB167 and potential for in-vivo PET.

Sigma(1) and sigma(2) receptors have been detected in many tissues and are highly expressed in several tumour cell lines from various tissues. The high level of expression observed for sigma receptors and their involvement in cell proliferation and apoptosis has led to the development of several sigma ligands in order to obtain a molecular probe for in-vivo diagnostic imaging techniques such as positron emission tomography (PET) and single photon emission computerized tomography (SPECT). The EMT-6 cells implanted in mice were a good model for evaluating the proliferation of solid tumours by in-vivo PET. Moreover, we developed the sigma ligand PB167, a cyclohexylpiperazine derivative, previously evaluated for sigma(2) receptor affinity and activity in standard protocols. The related results encouraged us to verify if this compound could be developed as a radiotracer for in-vivo PET in order to visualize sigma(2) receptors expressed in EMT-6 cells when implanted in mice. This perspective was thought to be favourable because PB167 bears a methoxy substituent on the tetraline nucleus, an easy point for (11)C labelling. The aims of this preliminary study were both to assess the relative distribution of sigma(1) and sigma(2) receptors in EMT-6 cells and to verify if PB167 could be developed as a sigma(2) radiotracer for in-vivo PET. The results showed that both sigma(1) and sigma(2) receptors were overexpressed in EMT-6 cells and that the ligand PB167 can be positively considered for radiosynthesis preparation in order to suitably visualize sigma(2) receptors by the in-vivo PET technique and correlate their presence to tumour proliferation.

Animals↗

PubMed2004

Structure-affinity relationship study on N-(1,2,3,4-tetrahydronaphthalen-1-yl)-4-aryl-1-piperazinealkylamides, a new class of 5-hydroxytryptamine7 receptor agents.

A series of N-(1,2,3,4-tetrahydronaphthalen-1-yl)-4-aryl-1-piperazinealkylamides was prepared and their affinity for serotonin (5-hydroxytryptamine, 5-HT) 5-HT7, 5-HT(1A), and 5-HT(2A) receptors was measured by in vitro binding assays. In relation to 5-HT7 receptor affinity, receptor binding studies indicated that (i) the optimal alkyl chain length was five methylenes, (ii) an unsubstituted 1,2,3,4-tetrahydronaphthalenyl nucleus was preferred, and (iii) the substitution pattern of the aryl ring linked to the piperazine ring played a crucial role. Several compound with high affinity for 5-HT7 receptors were identified. Among them, 4-(2-methoxyphenyl)-N-(1,2,3,4-tetrahydronaphthalen-1-yl)-1-piperazinehexanamide (28), 4-(2-acetylphenyl)-N-(1,2,3,4-tetrahydronaphthalen-1-yl)-1-piperazinehexanamide (34), 4-(2-methylthiophenyl)-N-(1,2,3,4-tetrahydronaphthalen-1-yl)-1-piperazinehexanamide (44), 4-(2-hydroxyphenyl)-N-(1,2,3,4-tetrahydronaphthalen-1-yl)-1-piperazinehexanamide (46), and 4-(2-methylphenyl)-N-(1,2,3,4-tetrahydronaphthalen-1-yl)-1-piperazinehexanamide (49) were assayed for the 5-HT7 receptor-mediated relaxation of substance P-induced guinea pig ileum contraction. Compounds 28, 44, and 49 behaved as full agonists and compound 34 as a partial agonist, whereas derivative 46 acted as an antagonist. Among the compounds presented here, it emerged that 44 was identified as a potent 5-HT7 receptor agonist (Ki = 0.22 nM, EC50 = 2.56 microM), endowed with selectivity over 5-HT(1A) and 5-HT(2A) receptors (200-fold and >1000-fold, respectively).

Amides↗

PubMed2004

Antiproliferative and cytotoxic effects of some sigma2 agonists and sigma1 antagonists in tumour cell lines.

To establish the activity of sigma ligands at sigma1 and sigma2 receptor, we chose two tumour cell lines, the human SK-N-SH neuroblastoma and the rat C6 glioma lines, which express sigma2 receptors at a high density and sigma1 receptors in their high-affinity or low-affinity state. We tested the sigma2 receptor agonist PB28 and the sigma2 antagonist AC927, and (+)-pentazocine and NE100 as agonist and antagonist, respectively, at sigma1 receptors, with regard to antiproliferative and cytotoxic effects. In addition, 1,3-di(2-tolyl)guanidine (DTG) and haloperidol were tested as reference compounds displaying nearly equipotent sigma affinity (sigma2>sigma1 and sigma1>sigma2, respectively). In both SK-N-SH and C6 cells, PB28 and NE100 displayed the most potent results both in antiproliferative and cytotoxic assay while AC927 and (+)-pentazocine were inactive in both assays. The cytotoxic and antiproliferative effects of DTG and haloperidol reflected their sigma1 antagonist activity and sigma2 agonist activity. Moreover, our results in the tumour cell lines correlated well with those for sigma2 activity found previously in a functional assay in the guinea-pig bladder. These findings establish a new model for evaluating both sigma2 and sigma1 receptor activity of sigma ligands, which could be useful for developing new ligands having mixed sigma2 agonist/sigma1 antagonist activity as potential antineoplastic agents.

Animals↗