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G Nocentini

Publications and source records attributed to G Nocentini.

At least 19 recordsLinked to original sources
PubMed2003

Dietary alpha-linolenic acid reduces COX-2 expression and induces apoptosis of hepatoma cells.

Fatty acid synthetase (FAS) is overexpressed in various tumor tissues, and its inhibition and/or malonyl-CoA accumulation have been correlated to apoptosis of tumor cells. It is widely recognized that both omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) depress FAS expression in liver, although epidemiological and experimental reports attribute antitumor properties only to omega-3 PUFA. Therefore, we investigated whether lipogenic gene expression in tumor cells is differently regulated by omega-6 and omega-3 PUFAs. Morris hepatoma 3924A cells were implanted subcutaneously in the hind legs of ACI/T rats preconditioned with high-lipid diets enriched with linoleic acid or alpha-linolenic acid. Both-high lipid diets depressed the expression of FAS and acetyl-CoA carboxylase in tumor tissue, this effect correlating with a decrease in the mRNA level of their common sterol regulatory element binding protein-1 transcription factor. Hepatoma cells grown in rats on either diet did not accumulate malonyl-CoA. Apoptosis of hepatoma cells was induced by the alpha-linolenic acid-enriched diet but not by the linoleic acid-enriched diet. Therefore, in this experimental model, apoptosis is apparently independent of the inhibition of fatty acid synthesis and of malonyl-CoA cytotoxicity. Conversely, it was observed that apoptosis induced by the alpha-linolenic acid-enriched diet correlated with a decrease in arachidonate content in hepatoma cells and decreased cyclooxygenase-2 expression.

Acetyl-CoA Carboxylase↗
PubMed2003

Enhanced expression of hepatic lipogenic enzymes in an animal model of sedentariness.

The hindlimb-suspended rat was used as animal model to investigate the effects induced by immobilization of the skeletal muscle in the expression of the genes encoding hepatic lipogenic enzymes. Following a 14-day period of immobilization, rats were injected intraperitoneally with radioactive acetate, and the labeling of hepatic lipids and cholesterol was evaluated 15 min after the isotope injection. The incorporation of labeled acetate in lipids and cholesterol was almost three times higher in the liver of immobilized rats than in control animals as a consequence of the enhanced transcription of the genes encoding acetyl-CoA synthase, acetyl-CoA carboxylase, fatty acid synthase, and 3-hydroxy-3-methylglutaryl-CoA reductase. The high expression of the key enzymes for fatty acid and cholesterol synthesis induced by immobilization was not paralleled by an increase of the hepatic sterol-regulatory element binding protein (SREBP)-1 and SREBP-2 mRNA content. However, the expression of the mature form of SREBP-1 and SREBP-2 was higher in the nuclear fraction of immobilized rat liver than in controls due to a significant increase of the cleavage of the native proteins. Immobilization also affected the expression of proteins involved in lipid degradation. In fact, the hepatic content of peroxisome proliferator-activated receptor-alpha (PPARalpha) mRNA and of PPARalpha target genes encoding carnitine palmitoyl transferase-1 and acyl-CoA oxidase were significantly increased upon immobilization.

Acetates↗
PubMed2001

Differentiation of Ly49s-positive or -negative natural killer cells is inhibited by anti-H-2b monoclonal antibodies acting at the level of bone marrow progenitors from B6 mice.

To investigate the role of MHC class I on in vitro differentiation of natural killer (NK) cells, a CD44low/-CD2-classlow population was isolated from mouse bone marrow. This population, which lacked expression of NK-1.1, Ly49A, Ly49C/I, and Ly49G, generated populations of NK-1.1+ NK cells expressing Ly49A, Ly49C/I, or Ly49G when cocultured for 13 days with syngeneic supportive stromal cells in the presence of interleukin 2. Ly49A and Ly49C/I were absent on the progeny of progenitors tested after 7 days of culture but were expressed as a late event together with low-level expression of NK-1.1, from day 8 of culture. The addition of anti-H-2b monoclonal antibody to cultures at day 0 inhibited proliferation of progenitors supported by either syngeneic, allogeneic, or H-2b-deficient stromal cells, thus suggesting that the effect was not exerted on stromal cells. Additional analyses demonstrated that class Ilow progenitors generated class I+ cells on which the anti-H-2b monoclonal antibody exerted its inhibitory effect.

Animals↗
PubMed2000

Gene structure and chromosomal assignment of mouse GITR, a member of the tumor necrosis factor/nerve growth factor receptor family.

GITR is a type I transmembrane protein that belongs to the tumor necrosis factor/nerve growth factor receptor (TNF/NGFR) family. This receptor is preferentially expressed in activated T lymphocytes and may function as signaling molecule during T-cell development. In the present study, we examined the genomic organization of the entire mouse GITR (mGITR) gene. The gene spans a 2543-bp region and consists of five exons (with a length ranging from 88 bp to 395 bp) and four introns (67 bp to 778 bp). In agreement with GITR expression in activated T cells, consensus elements for transcription factors involved in T-cell development and activation were identified in the 5' flanking region, including a consensus element for NF-kappaB. Two highly significant binding sites for MyoD and one binding site for myogenin were also found, suggesting involvement of GITR in muscle development. The mGITR gene contains 17 transcription initiation sites distributed over a 76-bp region, all used with the same frequency. We localized mGITR to the murine chromosome 4 (E region), where other 4 TNF/NGFR members localize, including m4-1BB and mOX40. These results further indicate that GITR shares several features with OX40, 4-1BB, and CD27, suggesting the existence of a new subfamily of the TNFR family, as also confirmed by the similarity of their cytoplasmic domains.

Amino Acid Sequence↗
PubMed1999

Design and synthesis of modified quinolones as antitumoral acridones.

The bacterial topoisomerase II (DNA gyrase) and the mammalian topoisomerase II represent the cellular targets for quinolone antibacterials and a wide variety of anticancer drugs, respectively. In view of the mechanistic similarities and sequence homologies exhibited by the two enzymes, tentative efforts to selectively shift from an antibacterial to an antitumoral activity was made by synthesizing a series of modified tricyclic quinolones, in which the essential 3-carboxylic function is surrogated by phenolic OH and the classic C-6 fluorine atom is replaced by a NH2 group. The resulting 7-amino-9-acridone derivatives were assayed for their antibacterial as well as cytotoxic activities. No antibacterial activity was found. On the other hand, many derivatives showed significant cytotoxic activity against both HL-60 and P388 leukemias and a wide panel of human and rodent solid tumor cells, derivatives 25 and 26 displaying the best overall antiproliferative activity. Against the LoVo cell line, derivative 25 exhibited higher cytotoxic effects than etoposide.

Acridines↗
PubMed1999

Angiotensin converting enzyme deletion allele in different kinds of dementia disorders.

In order to verify the association of Angiotensin converting enzyme (ACE) gene with different kinds of dementia, as well as its association with APO-E (genotype), we performed ACE genotyping in subjects with late-onset probable Alzheimer's disease (LOAD, n = 64), early-onset probable Alzheimer's disease (EOAD, n = 32), possible Alzheimer's disease (pAD, n = 44), vascular dementia (VD, n = 12), age-associated memory impairment (AAMI, n = 15) and 40 healthy age-matched controls, who were previously characterized for APO-E. After the principal component analysis ACE D and Apo-Eepsilon4 alleles disclosed the highest prevalence in the cognitively impaired groups of subjects, Apo-Eepsilon4 being more specific for LOAD and pAD. ACE D allele seems to be an unspecific susceptibility factor for mental decline.

Age Factors↗
PubMed1999

TCR kappa, a new splicing of the murine TCR zeta gene locus, is modulated by glucocorticoid treatment.

T-cell receptor (TCR) is a multichain receptor in which the TCRzeta subunit is important for membrane assembly and signal transduction. Four alternative splicings of the murine TCRzeta gene locus have been previously described. We here describe a new alternative splicing of murine TCRzeta gene, TCRkappa, cloned by RT-PCR, that is encoded by exons 1-7, a portion of exon 9 and the whole exon 10 of TCRzeta gene. The protein encoded by TCRkappa mRNA is identical to that encoded by TCReta mRNA, because the stop codon is present in the exon 9 before splicing with exon 10. RNAse protection assays carried out on total RNA from thymocytes indicate that TCRkappa mRNA is 1 half with respect to TCReta mRNA, suggesting that TCRkappa mRNA contributes to determine the TCReta protein levels. The 3' untranslated region of TCRkappa mRNA is different from that of TCReta and this might lead to different t(1/2) for each species in vivo. We also show that dexamethasone (DEX), a synthetic glucocorticoid hormone, increases the amount of TCRkappa in the hybridoma T-cell line 3DO (about 5-fold increase), as indicated by reverse transcriptase-polymerase chain reaction (RT-PCR) and RNAse protection assays. This newly described effect of DEX may constitute a further molecular mechanism that contributes to its immunomodulating activity.

Alternative Splicing↗
PubMed1997

Apolipoprotein-E genotype in normal aging, age-associated memory impairment, Alzheimer's disease and vascular dementia patients.

Apolipoprotein-E (Apo-E) genotype and allele frequencies were evaluated in patients with late-onset probable Alzheimer's disease (LOAD; n = 64), early-onset probable Alzheimer's disease (EOAD; n = 32), possible Alzheimer's disease (pAD; n = 44), vascular dementia (VD; n = 12), age-associated memory impairment (AAMI; n = 15) and 40 healthy age-matched controls. APO-E was performed by polymerase chain reaction products digested by the restriction enzyme HhaI. A statistically significant increase of epsilon4 frequency was found in LOAD as compared to the other groups, and in pAD with respect to controls, while VD and AAMI groups did not disclose any difference as regards to control subjects. Multivariate analysis showed a significant association of epsilon4 with female gender. Our results confirm the increased frequency of epsilon4 in both probable and possible LOAD, failing to show a similar trend in VD and AAMI.

Adult↗
PubMed1997

Short-term dexamethasone treatment modulates the expression of the murine TCR zeta gene locus.

Glucocorticoids (GCH) are highly effective agents in controlling inflammation and immune response. We studied the effect of the synthetic GCH dexamethasone (DEX) on the expression of TCR zeta gene splicings that code for some chains belonging to the T-cell receptor (TCR)/CD3 complex. In the DEX-treated hybridoma T-cell line 3DO, TCR zeta gene splicings increase within the first 24 hr (about fourfold increase), as demonstrated by reverse transcriptase-polymerase chain reaction and RNase protection assay. This increase is due to the stimulation of TCR zeta gene locus transcription, as demonstrated by the "run-on" assay. A similar upregulation was observed in murine thymocytes following in vivo DEX treatment. As a consequence of TCR zeta gene locus modulation, the expression of the spliced mRNAs coding for TCR zeta and TCR eta subunits is increased, whereas their relative ratio is only slightly changed. Indeed, the amount of TCR zeta protein in 24-hr DEX-treated cells is fivefold more than that in the untreated cells. A similar effect was seen in 3DO cells treated with hydrocortisone but not in those treated with testosterone. TCR zeta protein increase was confined to the cytoplasm and therefore TCR/CD3 complex expression did not increase. This newly described effect of DEX may constitute an additional molecular mechanism that contributes to its immunomodulating activity.

Animals↗
PubMed1997

A new member of the tumor necrosis factor/nerve growth factor receptor family inhibits T cell receptor-induced apoptosis.

By comparing untreated and dexamethasone-treated murine T cell hybridoma (3DO) cells by the differential display technique, we have cloned a new gene, GITR (glucocorticoid-induced tumor necrosis factor receptor family-related gene) encoding a new member of the tumor necrosis factor/nerve growth factor receptor family. GITR is a 228-amino acids type I transmembrane protein characterized by three cysteine pseudorepeats in the extracellular domain and similar to CD27 and 4-1BB in the intracellular domain. GITR resulted to be expressed in normal T lymphocytes from thymus, spleen, and lymph nodes, although no expression was detected in other nonlymphoid tissues, including brain, kidney, and liver. Furthermore, GITR expression was induced in T lymphocytes upon activation by anti-CD3 mAb, Con A, or phorbol 12-myristate 13-acetate plus Ca-ionophore treatment. The constitutive expression of a transfected GITR gene induced resistance to anti-CD3 mAb-induced apoptosis, whereas antisense GITR mRNA expression lead to increased sensitivity. The protection toward T cell receptor-induced apoptosis was specific, because other apoptotic signals (Fas triggering, dexamethasone treatment, or UV irradiation) were not modulated by GITR transfection. Thus, GITR is a new member of tumor necrosis factor/nerve growth factor receptor family involved in the regulation of T cell receptor-mediated cell death.

Amino Acid Sequence↗
PubMed1997

Antitumor activity of 2,2'-bipyridyl-6-carbothioamide: a ribonucleotide reductase inhibitor.

1. 2,2'-Bipyridyl-6-carbothioamide (BPYTA) is a synthesized compound with chelating properties demonstrating in vitro and in vivo antitumor activity. 2. The BPYTA cytotoxic effect is mainly due to the inhibition of ribonucleotide reductase (RR), a key enzyme in proliferating cells. The active form of BPYTA is its iron chelate [BPYTA-Fe(II), molar ratio 2:1], which destroys the tyrosyl radical of RR small subunit (R2). 3. The copper chelate of BPYTA [BPYTA-Cu(II), molar ratio 2:1] also has antiproliferative activity, but RR is not the only intracellular target. 4. BPYTA potently synergizes in vitro with hydroxyurea, the most widely used R2 inhibitor.

2,2'-Dipyridyl↗
PubMed1997

Effect of dexamethasone on T-cell receptor/CD3 expression.

Glucocorticoid hormones (GCH) are anti-inflammatory and immunosuppressive agents that inhibit T-cell growth and activation. Since the T-cell receptor (TCR)/CD3 complex mediates T-lymphocyte activation, we studied the effect of in vitro dexamethasone (DEX), a synthetic GCH, on TCR/CD3 expression. DEX-treatment of a hybridoma T-cell line and normal un-transformed T-cell clones induced a decrease of the TCR/ CD3 membrane expression after 4 days. After 4 weeks, TCR/CD3 was undetectable. However, the amount of mRNAs coding TCR/CD3 chains, including TCR alpha, TCR beta, CD3 gamma, CD3 theta and CD3 epsilon, as well as the amount of CD3 epsilon protein, a major component of the complex, were unaltered. By contrast, a decrease of the mRNAs deriving from the TCR zeta gene locus, as well as of the TCR zeta protein which is responsible for the membrane expression of the TCR/CD3 complex, was induced. These data suggest that the down-modulation of TCR expression is due to the diminution of TCR zeta gene products in DEX-treated cells.

Animals↗
PubMed1997

Hydroxyurea induces the gene expression and synthesis of proinflammatory cytokines in vivo.

The anticancer agent hydroxyurea (HU) was previously found to cause dose-dependent adrenal activation in the rat. The increased secretion of corticosterone (CORT) that results appeared to protect animals against HU toxicity, which was dramatically enhanced in adrenalectomized (ADX) rats. Similarities with the endocrine and toxicological profiles of proinflammatory cytokines such as interleukin (IL)-1 and tumor necrosis factor (TNF) led us to suggest that these effects of HU might be mediated by an increased synthesis of these cytokines. The goal of this study was therefore to demonstrate that HU induces the gene expression and synthesis of proinflammatory cytokines in vivo. Intact and ADX rats were treated with HU, mRNA was extracted from spleen cells 2 and 24 hr after treatment and message levels for IL-1 alpha, IL-2, IL-4, IL-6, TNF alpha and interferon-gamma were evaluated using the reverse transcriptase-polymerase chain reaction technique. In some experiments, circulating levels of CORT and TNF were also measured. We found that transcripts of the proinflammatory cytokines, TNF, IL-6 and (though less clearly) IL-1 alpha, were expressed in the majority of intact rats treated with HU but were absent or less evident in most controls. In contrast, gene expression of IL-2, IL-4 and interferon-gamma was not influenced by drug treatment. Adrenalectomy markedly enhanced the effects of HU. Twenty-four hours after administration of the drug, the expression of TNF and IL-6 mRNAs was still higher in ADX rats compared with intact animals. Parallel measurements of plasma CORT levels revealed that gene expression of IL-1 alpha and, to a lesser extent, TNF was inversely related to levels of circulating CORT. Adrenalectomy per se caused a significant increase in plasma TNF levels compared with intact controls. Hydroxyurea elicited significant increases in circulating TNF in both ADX and intact rats. These findings lend support to our working hypothesis and provide an explanation for both the rise in glucocorticoid secretion induced by HU in intact rats and the increase in lethality observed in animals with disruptions of the hypothalamo-pituitary-adrenal axis.

Adrenalectomy↗
PubMed1996

The 2,2'-bipyridyl-6-carbothioamide copper (II) complex differs from the iron (II) complex in its biochemical effects in tumor cells, suggesting possible differences in the mechanism leading to cytotoxicity.

2,2'-bipyridyl-6-carbothioamide (BPYTA) is an antitumor agent with chelating properties. It has previously been shown that the R2 subunit of ribonucleotide reductase (RR) is its major cellular target, but RR inhibition is observed only in the presence of ferrous iron (BPYTA-Fe, molar ratio 2:1). Because the copper (II) complex of BPYTA (BPYTA-Cu, molar ratio 1:1)) has in vitro antitumor activity comparable to that of BPYTA-Fe, we studied the mechanism of action of this new metal complex. Spectorphotometric and HPLC studies demonstrated that, at pH 7.5, BPYTA-Cu is stable at molar ratio 2:1 and copper is in its favored oxidized form [BPYTA-Cu(II)]. Electron paramagnetic resonance (EPR) studies with mouse recombinant R2 demonstrated that BPYTA-Cu destroys the R2 tyrosyl radical at the same concentration at which BPYTA-Fe does (78% vs 73% destruction at 200 microM, with 5 min of contact), but R2 inhibition is not time-dependent. Studies of the metabolism of [14C] cytidine suggest that the cytotoxic activity of BPYTA-Cu can be explained in terms of RR inhibition. However, the significant inhibition of RNA synthesis and the lack of cross-resistance to BPYTA-Cu of cell lines resistant to other RR inhibitors suggest that BPYTA-Cu may have more than one cellular target. Moreover, cell proliferation studies suggest that, unlike BPYTA-Fe, BPYTA-Cu displays its activity immediately after contact with the target cells. Our study demonstrates that significant differences in the biochemical effects of BPYTA and, perhaps, also its mechanism of action are due solely to the bonded transition metalloelement. This might also be the case with other chelators that demonstrate cytotoxic activity following metalloelement chelation.

2,2'-Dipyridyl↗