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S Beninati

Publications and source records attributed to S Beninati.

At least 19 recordsLinked to original sources
PubMed2006

Selenomethionine induces polyamine biosynthesis in regenerating rat liver tissue.

Our study was undertaken to elucidate the effects of selenomethionine (SeMet) on polyamine metabolism in regenerating rat liver tissue, as useful model of rapidly growing normal tissue. We have examined the levels of spermine, spermidine and putrescine in liver tissue. At the same time we have evaluated the activities of polyamine oxidase (PAO) and diamine oxidase (DAO), the catabolic enzymes of polyamine metabolism. The obtained results suggest that polyamine levels in regenerating liver tissue, at 7(th) day after two-thirds partial hepatectomy, were higher in comparison with control group. The administration of selenomethionine to hepatectomized animals during seven days, in a single daily dose of 2.5 microg/100 g body weight, increases the amount of spermine and spermidine; the level of putrescine does not change under the influence of SeMet in regenerating rat liver tissue.PAO activity is lower in regenerating hepatic tissue than in control group. Supplementation of hepatectomized animals with SeMet significantly decreases the activity of this enzyme. DAO activity was significantly higher in hepatectomized and in operated animals treated with SeMet compared to the sham-operated and control ones. The differential sensitivity observed in our model of highly proliferating normal tissue to SeMet, compared with the reported anticancer activity of this molecule is discussed.

Amine Oxidase (Copper-Containing)↗
PubMed2006

Enhancement of transglutaminase activity and polyamine depletion in B16-F10 melanoma cells by flavonoids naringenin and hesperitin correlate to reduction of the in vivo metastatic potential.

The in vitro and in vivo effects of two flavonons, naringenin (NG) and hesperitin (HP) on the proliferation rate of highly metastatic murine B16-F10 melanoma cell were investigated. NG or HP treatment of melanoma cells produced a remarkable reduction of cell proliferation, paralleled with both the lowering of the intracellular levels of polyamine, spermidine and spermine and the enhancement of transglutaminase (TGase, EC 2.3.2.13) activity. Orally administered NG or HP in C57BL6/N mice inoculated with B16-F10 cells affected the pulmonary invasion of melanoma cells in an in vivo metastatic assay. The number of lung metastases detected by a computerized image analyzer was reduced, compared to untreated animals, by about 69% in NG-treated mice and by about 36% in HP-treated mice. Survival studies showed that 50% of the NG-treated animals died 38 +/- 3.1 days after tumor cell injection (control group: 18 +/- 1.5 days) and HP-treated mice died 27 +/- 2.3 days after cell inoculation. Taken together, these findings provide further evidences for the potential anticancer properties of dietary flavonoids as chemopreventive agents against malignant melanoma.

Animals↗
PubMed2006

The role of L-arginine in toxic liver failure: interrelation of arginase, polyamine catabolic enzymes and nitric oxide synthase.

The existing interrelation in metabolic pathways of L-arginine to polyamines, nitric oxide (NO) and urea synthesis could be affected in sepsis, inflammation, intoxication and other conditions. The role of polyamines and NO in the toxic effect of mercury chloride on rat liver function was studied. Administration of mercury chloride for 24 h led to significantly elevated plasma activities of Alanine transaminase (ALT) and Aspartate transaminase (AST). Malondyaldehyde (MDA) levels were unaffected (p > 0.05) and arginase activity was significantly decreased (p < 0.05) while nitrate/nitrite production was significantly elevated (p < 0.001) in liver tissue. Polyamine oxidase (PAO) and diamine oxidase (DAO) activities, enzymes involved in catabolism of polyamines, were decreased. L-arginine supplementation to intoxicated rats potentiated the effect of mercury chloride on NO production and it was ineffective on arginase activity. Results obtained in this study show that mercury chloride-induced toxicity leads to abnormally high levels of ALT and AST that may indicate liver damage with the involvement of polyamine catabolic enzymes and NO.

Amine Oxidase (Copper-Containing)↗
PubMed2005

Alternative therapy of earth elements increases the chondroprotective effects of chondroitin sulfate in mice.

The administration of mineral sulphur water is an alternative experimental approach for the treatment of rheumatic diseases, such as osteoarthritis (OA), that cause the degeneration of bone and cartilage and sufferance to the patients. Chondroitin sulfate (CS) is a symptomatic slow acting nutropeucital agent currently used in molecular therapy of OA. Therefore, we have studied the role and efficacy of the selective soil paste from the mineral sulphur enriched spring (mud)-therapy alone or in combination with CS in the treatment of OA. The study was performed on 40 C57 Black 6N mice, an experimental model which spontaneously develop an osteoarthritic process. The animals were divided in 4 groups and were treated with the single agents or with the combination. After 30 days of treatment all the mice were sacrificed and right knees and blood were collected. It was found that CS determined a reduction of radiological and histological features of chondrodegeneration and that mud-therapy increased the effects of CS in the animal group treated with the combination. However, the effects of thermal therapy alone were not statistically significant. Since OA is characterized by an increase of the production of nitric oxide (NO) by chondrocytes in extracellular matrix with its consequent elevation in serum and synovial fluid, we have evaluated the effects of the treatments on serum NO levels. CS alone induced a statistically significant reduction of NO serum levels (90+/-13 micromM vs 219+/-60 microM of control group, P<0.05) while mud-therapy alone induced a not statistically significant reduction of serum NO (170+/-62 microM, P>0.05). However, the latter strongly potentiated the decrease of serum NO induced by CS (31+/-1.5 microM) with a high statistical significance if compared to both the control group (P<0.01) and the CS-treated group (P<0.05). In conclusion, this study demonstrates that mud-therapy with sulphur mineral water could represent an important phase of the therapeutic strategy of OA. This experimental strategy could integrate and potentiate the standard pharmacological tools. Moreover, we have set a valid experimental in vivo model for the study of the thermal effects on the development of OA.

Animals↗
PubMed2004

Protein-polyamine conjugation by transglutaminase in cancer cell differentiation: review article.

Considerable and intense progress has been made in the understanding of the chemistry, molecular biology and cell biology of transglutaminases (TGases: EC 2.3.2.13). The knowledge that very different processes such as cell growth, reproduction and death are dependent on the presence of adequate levels of these enzymes and that the amount of both free and protein-conjugated polyamines, formed by the enzyme, are capable of modulating the differentiation and proliferative capability of several cell types, has prompted a multitude of researchers to study the role of these fascinating molecules in cancer cell differentiation.

Animals↗
PubMed2004

The transglutaminase family: an overview: minireview article.

The knowledge that very different processes such as normal and neoplastic cell growth, reproduction and death are dependent on the presence of adequate levels of transglutaminases (TGase: EC 2.3.2.13) and that they are capable of affecting the differentiation and proliferative capability of several cell types, has prompted a multitude of researchers to study these fascinating molecules. In the following overview we intend to summarize the currently known information on the biological significance of these enzymes.

Animals↗
PubMed2004

Translational and post-translational modifications of proteins as a new mechanism of action of alpha-interferon: review article.

Interferon-alpha (IFNalpha) is a recombinant protein widely used in the therapy of several neoplasms such as myeloma, renal cell carcinoma, epidermoid cervical and head and neck tumours and melanoma. IFNalpha, the first cytokine to be produced by recombinant DNA technology, has emerged as an important regulator of cancer cell growth and differentiation, affecting cellular communication and signal transduction pathways. However, the way by which tumour cell growth is directly suppressed by IFNalpha is not well known. Wide evidence exists on the possibility that cancer cells undergo apoptosis after the exposure to the cytokine. Here we will discuss data obtained by us and others on the post-translational regulation of the expression of proteins involved in the occurrence of apoptotic process such as tissue transglutaminase (tTG) or in the modulation of cell cycle such as the cyclin-dependent kinase inhibitor p27. This new way of regulation of p27 and tTG occurs through the modulation of their proteasome-dependent degradation induced by the cytokine. We will also review the involvement of protein synthesis machinery in the induction of cell growth inhibition by IFNalpha. In details, we will describe the effects of IFNalpha on the expression and activity of the protein kinase dependent from dsRNA (PKR) and on the eukaryotic initiation factor of protein synthesis 5A (eIF-5A) and their correlations with the regulation of cancer cell growth. These data strongly suggest that the antitumour activity of IFNalpha against human tumours could involve still unexplored mechanisms based on post-translational and translational control of the expression of proteins that regulate cell proliferation and apoptosis.

Animals↗
PubMed2001

Transglutaminase activity is involved in polyamine-induced programmed cell death.

Natural polyamines, i.e., putrescine, spermidine, and spermine, are ubiquitous molecules essential for cell proliferation and differentiation. In the present study, the effect of polyamines on primary cultures of bovine aortic endothelial cells (BAECs), rat aortic smooth muscle cells (RASMCs), and a human melanoma cell line was examined. While in the absence of fetal calf serum (FCS) polyamines had no effect on viability, in the presence of FCS spermidine and spermine, at concentrations close to physiologic levels, induced a dose-dependent cell death, whereas putrescine was ineffective. RASMCs were significantly more sensitive than other cells. FACS analysis, oligo-nucleosome ELISA, Hoechst nuclear staining, and Annexin V-FITC quantification showed that cell death was likely due to apoptosis. Cells exposed to spermidine showed a marked increase of intracellular transglutaminase (TGase) activity ( approximately 30-fold over control). Inhibitors of polyamine oxidation or inhibitors of TGase activity prevented polyamine-induced apoptosis. Moreover, tissue TGase overexpression significantly increased cell sensitivity to polyamine, suggesting that this effect is likely related to enhanced intracellular TGase activity. These data indicate that polyamines may modulate cell viability through a novel TGase-dependent process.

Animals↗
PubMed2001

The role of eukaryotic initiation factor 5A in the control of cell proliferation and apoptosis.

In the past years, the attention of scientists has mainly focused on the study of the genetic information and alterations that regulate eukaryotic cell proliferation and that lead to neoplastic transformation. An increasing series of data are emerging about the involvement of the initiation phase of translational processes in the control of cell proliferation. In this paper we review the novel insights on the biochemical and molecular events leading to the initiation and its involvement in cell proliferation and tumourigenesis. We describe the structure, regulation and proposed functions of the eukaryotic initiation factor 5A (eIF-5A) focusing the attention on its involvement in the regulation of apoptosis and cell proliferation. Moreover, we describe the modulation of its activity (through the reduction of hypusine synthesis) in apoptosis induced either by tissue transglutaminase or interferon a. Finally, we propose eIF-5A as an additional target of anti-cancer strategies.

Active Transport, Cell Nucleus↗
PubMed2001

Polymeric protein-polyamine conjugates: a new class of uremic toxins affecting erythropoiesis.

BACKGROUND: Preliminary evidence on the accumulation of polyamine-protein conjugates (PPCs) was obtained in uremic patients. The presence of these substances in the plasma of hemodialysis (HD) patients was evaluated, and their possible contribution to uremic anemia was investigated by testing the effect of PPC synthesized in vitro on erythroid cell proliferation. METHODS: Plasma PPC was measured by high-performance liquid chromatography. The in vitro synthesis of PPC from human plasma was carried out by means of the enzyme transglutaminase in the presence of either [3H]-labeled or unlabeled spermidine (SPD). After gel filtration chromatography and detection of the fractions containing [3H]SPD, the latter were tested for their effect on mononuclear bone marrow cell proliferation. RESULTS: In three out of four patients examined, mainly SPD-protein conjugates (SPD-PC) were observed to accumulate during HD. The levels ranged from 0.17 to 4.93 pmol/mg proteins before dialysis, and these values increased at 30 minutes and at the end of the dialysis up to levels 11.90 pmol/mg. SPD-PC levels in healthy controls were 1.46 +/- 0.82. SPD-PCs synthesized in vitro were recovered in two main fractions showing a molecular weight of> 100 kD (peak 1) and of approximately 30 to 50 kD (peak 3), respectively. The SPD-PC contained in peak 1 showed the greatest inhibitory effect on colony-forming units-erythroid (CFU-E) proliferation without any appreciable effect on burst-forming units-erythroid (BFU-E). CONCLUSION: We demonstrate that SPD-PC can accumulate in HD patients. These substances, which affect CFU-E proliferation, can be considered as an at yet unrevealed class of uremic toxins contributing to the onset of the uremic anemia.

Aged↗
PubMed2000

Evaluation of the efficacy of potential antineoplastic drugs on tumour metastasis by a computer-assisted image analysis.

Computerised image analysis, performed on histological sections of (C57BL6/N) mouse lungs that had been intravenously (i.v.) injected with B16-F10 melanoma cells was used to develop a novel method to quantify the efficacy of potential antineoplastic drugs. This procedure allowed the evaluation of the rate of inhibition of growth and the anti-invasive capability of new molecules, thus resulting in more accurate data than that obtained from common macroscopical counting of surface metastatic foci. Several morphological parameters can be measured by this method: the percentage of tissue area occupied by metastases, which accounts for tumour implantation into the organ; the growth index, related to the size of the metastases, and the invasion index, related to the frequency of foci. These morphometric data were found to be correlated to the levels of lung hydroxyproline and transglutaminase activity, well known markers of tumour invasion and cell differentiation, respectively. The main objective of this computerised procedure was to evaluate how the tumour cell is affected in the host by the drug under investigation. The use of the method is exemplified by an analysis of the antitumour activity of some methylxanthines.

Animals↗
PubMed2000

Theophylline administration markedly reduces hepatic and pulmonary implantation of B16-F10 melanoma cells in mice.

Theophylline-treated B16-F10 melanoma cells show a lower experimental metastatic potential in vivo. To identify the possible mechanism(s) involved and on the basis of previous reports, we tested the induction of apoptosis in B16-F10 cells. Fluorescence activated cell sorter (FACS) analysis and p53 overexpression in theophylline-treated B16-F10 melanoma cells appeared to suggest enhanced cell death by apoptosis. The in vivo effects of orally administered theophylline in mice were investigated using different treatment schedules in mice that had undergone hepatic or pulmonary colonization with tumour cells. Mice received theophylline in their drinking water according to different protocols: (i) from 3 days before tumour cell inoculation until animal sacrifice ('early treatment'); (ii) from 3 days before until 3 days after tumour cell inoculation ('short treatment'); or (iii) from 3 days after tumour cell inoculation until animal sacrifice ('late treatment'). In the 'early treatment' group, the number of melanoma foci was reduced by 92.3% in the liver and 81.4% in the lung compared with control animals (P < 0.001). In the 'short treatment' group, there was an 80.2% and 72.2% reduction in liver and lung metastases, respectively (P < 0.001). In the 'late treatment' group, the inhibition of metastasis was 59.7% for liver and 45.3% for lung (P < 0.005). Survival studies showed that 50% of the 'early' theophylline-treated animals died 33.2 +/- 2.0 days after intrasplenic injection (control group: 23.1 1.8 days; P < 0.001) and 33.9 +/- 2.5 days after tail vein injection (control group: 24.1 +/- 1.4 days; P < 0.001). Taken together, these observations provide useful information for the potential clinical application of theophylline as a chemotherapeutic agent against malignant melanoma.

Animals↗
PubMed1999

Structural organization of the human eukaryotic initiation factor 5A precursor and its site-directed variant Lys50-->Arg.

The molecular properties of the human eukaryotic initiation factor 5A precursor and its site directed Lys50-->Arg variant have been investigated and compared. Structure perturbation methods were used to gain information about the protein architecture in solution. Intrinsic and extrinsic spectroscopic probes strategically located in the protein matrix detected the independent unfolding of two molecular regions. Three cysteines out of four were titrated in the native protein and the peculiar presence of a tyrosinate band at neutral pH was detected. At alkaline pH only two tyrosines out of three were titratable in the native protein, with an apparent pK of about 9.9. Native protein and its Lys50-->Arg variant reacted in a similar fashion to guanidine and to pH variation, but differently to thermal stress. The complex thermal unfolding of both proteins indicated the presence of intermediates. Spectroscopic data showed that these intermediates are differently structured. Consequently, the two proteins seem to have different unfolding pathways.

Amino Acid Substitution↗
PubMed1998

Tissue transglutaminase expression affects hypusine metabolism in BALB/c 3T3 cells.

Post-translational formation of hypusine in eukaryotic initiation factor 5A (eIF-5A) is essential for cell viability. Recently, we showed that hypusine protein is an in vitro substrate for transglutaminases (TGases). We report the effect of tissue TGase expression on the in vivo hypusine metabolic pathway. The stable expression of tTGase in BALB/c 3T3 cells induced a 100-fold reduction of hypusine levels and a 50% increase of gamma-glutamyl-omega-hypusine formation. Such changes were paralleled by a consistent decrease in the free polyamine pool and an enhancement of their excretion and of the formation of their gamma-glutamyl derivatives. These effects occurred together with a significant reduction of cell proliferation. In this report we suggest, for the first time, that tTGase affects hypusine metabolism, thus regulating the eIF-5A activity and cell proliferation.

3T3 Cells↗
PubMed1998

Inhibition of melanoma pulmonary metastasis by methylxanthines due to decreased invasion and proliferation.

Theophylline- and caffeine-treated B16-F10 cells exhibited low adhesion to laminin/collagen type IV and reduced invasion through Matrigel in an in vitro assay. In contrast, theobromine appeared ineffective. When young adult C57BL/6 mice were injected intravenously with theophylline-treated B16-F10 cells, the number of surface lung tumours was markedly reduced. Densitometric analyses performed on digitalized microscopic images of histological sections of lung were used to estimate the frequency (number of lung foci; NLF) and the size (average area of metastatic foci; AMF) of the resulting tumour foci. These parameters were correlated to the proliferation (AMF) and invasion (NLF) of melanoma cells in vivo. The data showed a similar theophylline-induced decrease in the AMF and NLF values (71%, P < 0.01). Caffeine treatment produced a more pronounced decrease in the AMF (61%, P < 0.01) than in the NLF (25%, P < 0.01). To our knowledge, this is the first demonstration that theophylline and caffeine possess the capacity to inhibit not only cell proliferation, but also the metastatic behaviour of melanoma cancer cells.

Animals↗
PubMed1997

Interferon alpha2 recombinant and epidermal growth factor modulate proliferation and hypusine synthesis in human epidermoid cancer KB cells.

We previously found that interferon alpha2 recombinant (IFNalpha) increases the expression of epidermal growth factor receptor (EGF-R) in the human epidermoid cancer KB cell line. Here we report the effects of IFNalpha and epidermal growth factor (EGF) on KB cell cycle kinetics. IFNalpha (1000 i.u./ml) for 48 h decreased the S-phase fraction and diminished the expression of Ki67 and proliferating cell nuclear antigen on KB cells. Incubation of IFNalpha-treated KB cells with 10 nM EGF for 12 h reversed these effects. We then studied several biochemical markers of cell proliferation. Ornithine decarboxylase activity was decreased to about one-tenth by IFNalpha and partly restored by EGF. Hypusine is contained only in eukaryotic initiation factor 5A and its levels are correlated with cell proliferation. IFNalpha decreased hypusine synthesis by 75%; exposure of cells to EGF for 12 h restored hypusine synthesis almost completely. We also studied the effects of IFNalpha on the cytotoxicity of the recombinant toxin TP40, which inhibits elongation factor 2 through EGF-R binding and internalization. IFNalpha greatly enhanced the TP40-induced inhibition of protein synthesis in KB cells. In conclusion, IFNalpha, which affects protein synthesis machinery and increases EGF-R expression, enhances the tumoricidal activity of TP40 and hence could be useful in the setting of anti-cancer therapy.

Antineoplastic Agents↗
PubMed1996

Polyamines in frontal cortex of patients with Down syndrome and Alzheimer disease.

Polyamines may play an important role in brain development, mature brain function and also in neurodegenerative conditions. We investigated polyamine levels in frontal cortex of human post-mortem brain samples of elderly patients with Down syndrome (DS), Alzheimer disease (AD) and normal controls by means of chromatographic separation after dansylation. Spermidine and spermine concentrations were markedly decreased in DS and AD. Polyamine levels were neither related to age and post-mortem interval nor to choline acetyltransferase activity, as indicator of neuronal loss. Our results support the idea that besides other neurotransmitter systems, endogenous polyamine levels are altered in dementing illnesses such as Alzheimer disease and Down syndrome.

Aged↗