Publications by authors named "Silvia Filippi"

24 Publications

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Stereoselective Access to Antimelanoma Agents by Hybridization and Dimerization of Dihydroartemisinin and Artesunic acid.

ChemMedChem 2021 Apr 1. Epub 2021 Apr 1.

Department of Biological and Ecological Sciences, Univeristy of Viterbo, Via S.C. De Lellis s.n.c., 01100, Viterbo, Italy.

A library of five hybrids and six dimers of dihydroartemisinin and artesunic acid has been synthetized in a stereo-controlled manner and evaluated for the anticancer activity against metastatic melanoma cell line (RPMI7951). Among novel derivatives, three artesunic acid dimers showed antimelanoma activity and cancer selectivity, being not toxic on normal human fibroblast (C3PV) cell line. Among the three dimers, the one bearing 4-hydroxybenzyl alcohol as a spacer showed no cytotoxic effect (CC >300 μM) and high antimelanoma activity (IC =0.05 μM), which was two orders of magnitude higher than that of parent artesunic acid, and of the same order of commercial drug paclitaxel. In addition, this dimer showed cancer-type selectivity towards melanoma compared to prostate (PC3) and breast (MDA-MB-231) tumors. The occurrence of a radical mechanism was hypothesized by DFO and EPR analyses. Qualitative structure activity relationships highlighted the role of artesunic acid scaffold in the control of toxicity and antimelanoma activity.
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http://dx.doi.org/10.1002/cmdc.202100196DOI Listing
April 2021

Artemisinin Derivatives with Antimelanoma Activity Show Inhibitory Effect against Human DNA Topoisomerase 1.

ACS Med Chem Lett 2020 May 10;11(5):1035-1040. Epub 2020 Apr 10.

Dipartimento di Biologia, Università di Padova Distaccato presso il "Centro Linceo Beniamino Segre" Accademia Nazionale dei Lincei, Palazzo Corsini, Via della Lungara 10, 00165 Rome, Italy.

Artesunic acid and artemisinin are natural substances with promiscuous anticancer activity against different types of cancer cell lines. The mechanism of action of these compounds is associated with the formation of reactive radical species by cleavage of the sesquiterpene pharmacophore endoperoxide bridge. Here we suggested topoisomerase 1 as a possible molecular target for the improvement of the anticancer activity of these compounds. In this context, we report that novel hybrid and dimer derivatives of artesunic acid and artemisinin, bearing camptothecin and SN38 as side-chain biological effectors, can inhibit growth of yeast cells overexpressing human topoisomerase 1 and its enzymatic activity . These derivatives showed also anticancer activity in melanoma cell lines higher than camptothecin and paclitaxel. molecular docking calculations highlighted a common binding mode for the novel derivatives, with the sesquiterpene lactone scaffold being located near the traditional recognition site for camptothecin, while the bioactive side-chain effector laid in the camptothecin cleft.
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http://dx.doi.org/10.1021/acsmedchemlett.0c00131DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7236541PMC
May 2020

Synthesis and Evaluation of Artemisinin-Based Hybrid and Dimer Derivatives as Antimelanoma Agents.

ACS Omega 2020 Jan 27;5(1):243-251. Epub 2019 Dec 27.

Department of Ecological and Biological Sciences, University of Tuscia, via S. C. De Lellis 44, 01100, Viterbo, Italy.

A library of hybrid and dimer compounds based on the natural scaffold of artemisinin was synthesized. These derivatives were obtained by coupling of artemisinin derivatives, artesunate, and dihydroartemisinin with a panel of phytochemical compounds. The novel artemisinin-based hybrids and dimers were evaluated for their anticancer activity on a cervical cancer cell line (HeLa) and on three complementary metastatic melanoma cancer cell lines (SK-MEL3, SK-MEL24, and RPMI-7951). Two hybrid compounds obtained by coupling of artesunate with eugenol and tyrosol, and one of the dimer compounds containing curcumin, emerged as the most active and cancer-selective derivatives.
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http://dx.doi.org/10.1021/acsomega.9b02600DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6964273PMC
January 2020

In vitro evaluation of cytotoxic and genotoxic effects of Di(2-ethylhexyl)-phthalate (DEHP) on European sea bass (Dicentrarchus labrax) embryonic cell line.

Toxicol In Vitro 2019 Apr 24;56:118-125. Epub 2019 Jan 24.

Department of Ecological and Biological Sciences, Ichthyogenic Experimental Marine Center (CISMAR), University of Tuscia, Borgo Le Saline, 01016 Tarquinia, VT, Italy.

Marine litter is extensively distributed in the marine environment, and plastic debris, of which litter is mostly composed, can be a major source of pollutants. Among them, Di(2-ethylhexyl)-phthalate (DEHP) is the most abundantly used plastic additive, and it has been reported to affect biochemical processes both in humans and wildlife; however, studies on its toxicological effects on marine organisms are still scarce. In this survey, we studied the cytotoxic, genotoxic, and mutagenic effects of DEHP in European sea bass embryonic cell line (DLEC) by applying specific in vitro tests. Results showed a significant decrease in cell viability starting at 0.01 mM of DEHP after 24 h together with a significant increase in apoptosis and necrosis, morphological changes and cell detachment. Consistently, we detected a moderate increase in DNA strand breaks from 0.02 mM, and a dose-dependent increase in of micronucleus frequency from 0.01 mM, accompanied by a significant inhibition of cell proliferation, which suggested a possible aneugenic effect of this phthalate. Our results demonstrate that in vitro exposure to DEHP had a dose-dependent cytotoxic and genotoxic effects in DLEC cell line, encouraging further investigation into its effects in in vivo and/or ex vivo cell systems of marine organisms.
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http://dx.doi.org/10.1016/j.tiv.2019.01.017DOI Listing
April 2019

Oxidative nucleophilic substitution selectively produces cambinol derivatives with antiproliferative activity on bladder cancer cell lines.

Bioorg Med Chem Lett 2019 01 7;29(1):78-82. Epub 2018 Nov 7.

Department of Biological and Ecological Sciences, University of Tuscia, Largo dell'Università, Viterbo 01100, Italy.

Methyltrioxorhenium mediated oxidative addition/elimination nucleophilic substitution yielded alkylamino and arylamino cambinol derivatives characterized by anti-proliferative activity against wild-type and p53 mutated MGH-U1 and RT112 bladder cancer cell lines. Some of the novel compounds showed an activity higher than that of the lead compound. The reaction was highly regioselective, affording for the first time a panel of C-2 cambinol substitution products. Aliphatic primary and secondary amines, and primary aromatic amines, were used as nitrogen centered nucleophiles. Surprisingly, the antiproliferative activity of C-2 substituted cambinol derivatives was not correlated to the induction of p53 protein, as evaluated by the analysis of the cell viability on wild-type and p53 mutated cancer cell lines, and further confirmed by western blot analyses. These data suggest that they exert their antiproliferative activity by a mechanism completely different from cambinol.
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http://dx.doi.org/10.1016/j.bmcl.2018.11.006DOI Listing
January 2019

Modulation of chromatin conformation by the histone deacetylase inhibitor trichostatin A promotes the removal of radiation-induced lesions in ataxia telangiectasia cell lines.

Mutat Res Genet Toxicol Environ Mutagen 2018 Dec 15;836(Pt A):109-116. Epub 2018 Jun 15.

Department of Ecological and Biological Sciences (DEB), University of Tuscia, Via San Camillo de Lellis snc, 01100, Viterbo, Italy. Electronic address:

Ataxia telangiectasia is a rare autosomal recessive genome instability syndrome caused by mutations in the Ataxia Telangiectasia Mutated gene and characterized by a very high sensitivity to agents inducing double strand breaks such as ionizing radiation. In cells derived from ataxia telangiectasia patients a prominent enhancement of chromosomal aberrations is revealed as a consequence of this radiosensitivity characteristic, arising from defective DNA repair for a small fraction of breaks localized in the less accessible heterochromatin. Moreover, the signaling mediated by ataxia telangiectasia protein kinase also modifies chromatin structure. Even if there is a lot of knowledge concerning biochemical aspects of repair of double strand breaks, no conclusive results on radiosensitivity of structurally- and functionally-different chromatin are available, particularly in ataxia telangiectasia cells. Thus, a wild-type cell line and two ataxia telangiectasia patient derived ones could represent a suitable model to study the possible relationship between chromatin conformation and sensitivity to ionizing radiation. In this context, the effects of both cytosine arabinoside, an inhibitor of DNA repair synthesis, and trichostatin A, a histone deacetylase inhibitor, were tested in normal and ataxia telangiectasia lymphoblastoid cell lines carrying different mutation in the Ataxia Telangiectasia Mutated gene. The response to both inhibitors was investigated analyzing two endpoints, namely, chromosomal aberrations and the removal of DNA lesions by Comet assay, after exposure to X-rays. Results obtained suggest that the modulation of chromatin structure by trichostatin A leading to a more open conformation, decreases radiation-induced chromosomal aberrations in ataxia telangiectasia cells. The reduction in chromosomal instability can be attributed to an enhancement in DNA repair occurring in the presence of the histone deacetylase inhibitor, as its abolishment by the known inhibitor of DNA repair synthesis cytosine arabinoside clearly demonstrates. Data obtained could indicate a pivotal role of chromatin conformation in the radiosensitivity of ataxia telangiectasia cells.
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http://dx.doi.org/10.1016/j.mrgentox.2018.06.016DOI Listing
December 2018

Tyrosinase-Treated Hydroxytyrosol-Enriched Olive Vegetation Waste with Increased Antioxidant Activity Promotes Autophagy and Inhibits the Inflammatory Response in Human THP-1 Monocytes.

J Agric Food Chem 2018 Nov 7;66(46):12274-12284. Epub 2018 Nov 7.

Department of Ecological and Biological Sciences (DEB) , University of Tuscia , Viterbo , Italy.

Treatment of olive vegetation waste with tyrosinase immobilized on multiwalled carbon nanotubes increased the antioxidant activity as a consequence of the conversion of phenols to corresponding catechol derivatives, as evaluated by DPPH, Comet assay, and micronucleus analyses. During this transformation, 4-hydroxyphenethyl alcohol (tyrosol) was quantitatively converted to bioactive 3,4-dihydroxyphenethyl alcohol (hydroxytyrosol). The hydroxytyrosol-enriched olive vegetation waste also promoted autophagy and inhibited the inflammatory response in human THP-1 monocytes.
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http://dx.doi.org/10.1021/acs.jafc.8b03630DOI Listing
November 2018

Genetic effects in Helix aspersa near a coal plant revealed by the micronucleus test.

Ecotoxicology 2018 Mar 5;27(2):234-243. Epub 2018 Feb 5.

Department of Ecological and Biological Sciences, Tuscia University, Largo dell'Università snc, 01100, Viterbo, Italy.

Coal plants can be a major source of mutagenic pollutants. In this study we used the common land snail Helix aspersa, to detect the mutagenic effect of pollution from a coal plant in central Italy applying the micronucleus test (MN) on snail's haemocytes and evaluating trace elements concentration (As Cd, Pb, Hg, and Zn) in soil and snails. Snails from a biological farm were exposed for 13 days in five locations at different distances from the plant. Wild snails collected in the same locations were also analysed. MN frequency in exposed snails was significantly higher in four locations within 10 km from to the plant, with respect to the control and the farthest location. Comparing the MN frequency between farmed and wild snails, a significantly higher frequency emerged for the exposed snails in all locations except the farthest, likely indicating adaptation or selection of the wild organisms due to chronic exposure to pollutants. In natural snails significantly higher MN frequencies with near the plant emerged as well. Trace elements analysis showed significant correlations between MN frequencies and both Zn and As concentrations in soil, for both exposed and wild snails, and Zn and Pb concentrations in exposed snails. Our results were consistent with those previously obtained when evaluating primary DNA damage in natural snails from the same area and show that the snails near the plant were affected by a permanent cytogenetic damage. Moreover, they confirm the suitability of snails for biomonitoring the presence of pollutants with mutagenic effect.
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http://dx.doi.org/10.1007/s10646-018-1906-8DOI Listing
March 2018

Web based scoring is useful for validation and harmonisation of scoring criteria within RENEB.

Int J Radiat Biol 2017 01 22;93(1):110-117. Epub 2016 Aug 22.

s Stockholm University, Department of Molecular Biosciences, Stockholm , Sweden and Jan Kochanowski University , Kielce , Poland.

Purpose: To establish a training data set of digital images and to investigate the scoring criteria and dose assessment of the dicentric assay within the European network of biodosimetry (RENEB), a web based scoring inter-comparison was undertaken by 17 RENEB partners.

Materials And Methods: Two sets of 50 high resolution images were uploaded onto the RENEB website. One set included metaphases after a moderate exposure (1.3 Gy) and the other set consisted of metaphases after a high dose exposure (3.5 Gy). The laboratories used their own calibration curves for estimating doses based on observed aberration frequencies.

Results: The dose estimations and 95% confidence limits were compared to the actual doses and the corresponding z-values were satisfactory for the majority; only the dose estimations from two laboratories were too low or too high. The coefficients of variation were 17.6% for the moderate and 11.2% for the high dose. Metaphases with controversial results could be identified for training purposes.

Conclusions: Overall, the web based scoring of the two galleries by the 17 laboratories produced very good results. Application of web based scoring for the dicentric assay may therefore be a relevant strategy for an operational biodosimetry assistance network.
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http://dx.doi.org/10.1080/09553002.2016.1206228DOI Listing
January 2017

Integration of new biological and physical retrospective dosimetry methods into EU emergency response plans - joint RENEB and EURADOS inter-laboratory comparisons.

Int J Radiat Biol 2017 01 20;93(1):99-109. Epub 2016 Jul 20.

q National Center of Radiobiology and Radiation Protection (NCRRP) , Bulgaria.

Purpose: RENEB, 'Realising the European Network of Biodosimetry and Physical Retrospective Dosimetry,' is a network for research and emergency response mutual assistance in biodosimetry within the EU. Within this extremely active network, a number of new dosimetry methods have recently been proposed or developed. There is a requirement to test and/or validate these candidate techniques and inter-comparison exercises are a well-established method for such validation.

Materials And Methods: The authors present details of inter-comparisons of four such new methods: dicentric chromosome analysis including telomere and centromere staining; the gene expression assay carried out in whole blood; Raman spectroscopy on blood lymphocytes, and detection of radiation-induced thermoluminescent signals in glass screens taken from mobile phones.

Results: In general the results show good agreement between the laboratories and methods within the expected levels of uncertainty, and thus demonstrate that there is a lot of potential for each of the candidate techniques.

Conclusions: Further work is required before the new methods can be included within the suite of reliable dosimetry methods for use by RENEB partners and others in routine and emergency response scenarios.
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http://dx.doi.org/10.1080/09553002.2016.1206233DOI Listing
January 2017

The micronucleus assay in mammalian cells in vitro to assess health benefits of various phytochemicals.

Mutat Res Genet Toxicol Environ Mutagen 2015 Nov 30;793:79-85. Epub 2015 Jun 30.

Department of Ecological and Biological Sciences, University of Tuscia, Via San Camillo de Lellis snc, 01100 Viterbo, Italy.

We evaluated the protective effects of Gentiana lutea extracts (GLEx) and 6-Gingerol (6-G) on clastogenicity of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and 7,12-dimethylbenz(α) anthracene (DMBA) in vitro on HepG2 cells using the frequencies of induced micronuclei (MN) as the end point. Pre-, post- and simultaneous treatments with GLEx or 6-G and the carcinogens were carried out. Both GLEx post- and simultaneous treatments reduced the frequencies of MN induced by MNNG and DMBA. Probably this effect is due to an increase of cytostasis and a physico-chemical interaction between GLEx and DMBA under simultaneous treatment. Pre- and simultaneous treatments with 6-G significantly reduced the yield of MNNG-induced micronuclei without affecting % of cytostasis. Simultaneous treatment with 6-G plus DMBA resulted in reduction in the frequency of MN and an increase in cytotoxicity compared to sample treated alone with DMBA, whereas a post-treatment, caused a significant decrease in the yield of MN compared with DMBA alone without any cytotoxic effect. These results are compared with our earlier data obtained in the same system with other phytochemicals. It is concluded that for a critical evaluation of the protective effects of phytochemicals, both the influence on the induced MN and induced cytostasis have to be considered.
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http://dx.doi.org/10.1016/j.mrgentox.2015.06.016DOI Listing
November 2015

Pasta containing tartary buckwheat sprouts prevents DNA damage in spontaneously hypertensive rats.

Int J Food Sci Nutr 2015 11;66(5):574-8. Epub 2015 Jun 11.

Department of Ecological and Biological Sciences (DEB), Laboratory of Cellular and Molecular Nutrition, Tuscia University , Viterbo , Italy and.

Recent studies have shown that DNA damage occurs more often in hypertensive patients than non-hypertensive individuals. Here, we analyzed the in vivo effect of pasta containing 30% of tartary buckwheat sprouts (TBSP) on spontaneously hypertensive rats (SHRs) and normotensive Wistar Kyoto rats (WKY) to elucidate if TBSP could have an anti-genotoxic effect in hypertensive animal models. Both SHRs and WKY rats were divided into two groups and fed for six weeks with 5 g of TBSP and durum wheat flour commercial pasta, respectively. Our results showed that a diet rich in TBSP has anti-genotoxic effect. Indeed, SHRs fed with TBSP exhibited a significant decrease in DNA damage (38%) and more efficient DNA repair (84%) compared to SHRs fed with commercial pasta.
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http://dx.doi.org/10.3109/09637486.2015.1052378DOI Listing
May 2016

Identification of Novel Proteins Co-Purifying with Cockayne Syndrome Group B (CSB) Reveals Potential Roles for CSB in RNA Metabolism and Chromatin Dynamics.

PLoS One 2015 1;10(6):e0128558. Epub 2015 Jun 1.

Unit of Molecular Genetics of Aging, Department of Ecology and Biology, University of Tuscia, 01100, Viterbo, Italy.

The CSB protein, a member of the SWI/SNF ATP dependent chromatin remodeling family of proteins, plays a role in a sub-pathway of nucleotide excision repair (NER) known as transcription coupled repair (TCR). CSB is frequently mutated in Cockayne syndrome group B, a segmental progeroid human autosomal recessive disease characterized by growth failure and degeneration of multiple organs. Though initially classified as a DNA repair protein, recent studies have demonstrated that the loss of CSB results in pleiotropic effects. Identification of novel proteins belonging to the CSB interactome may be useful not only for predicting the molecular basis for diverse pathological symptoms of CS-B patients but also for unraveling the functions of CSB in addition to its authentic role in DNA repair. In this study, we performed tandem affinity purification (TAP) technology coupled with mass spectrometry and co-immunoprecipitation studies to identify and characterize the proteins that potentially interact with CSB-TAP. Our approach revealed 33 proteins that were not previously known to interact with CSB. These newly identified proteins indicate potential roles for CSB in RNA metabolism involving repression and activation of transcription process and in the maintenance of chromatin dynamics and integrity.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0128558PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4451243PMC
April 2016

Evaluation of the effects of ellagic acid (EA) on 7,12-dimethylbenz(α) anthracene (DMBA) induced micronuclei in mammalian cells in vitro and in vivo.

Toxicol Lett 2014 Jan 1;224(2):240-5. Epub 2013 Nov 1.

Department of Ecological and Biological Sciences, Università degli Studi della Tuscia, Largo dell'Università, snc, I-01100 Viterbo, Italy.

We evaluated the protective effects of EA, a promising dietary constituent against degenerative diseases, on the clastogenic action of the model carcinogen DMBA in vitro on human hepatoma cells (HepG2) and in vivo on bone marrow of mice, using the frequencies of induced micronuclei as the end point. Pre-, post- and simultaneous treatments with EA and the carcinogen were carried out in vitro. Simultaneous treatment with EA caused a statistically significant increase of DMBA induced MN, suggesting a direct interaction between the two agents. No significant reduction in DMBA induced MN was found by pre- or post treatment with EA. Similar effects were observed in the toxicity assay. In in vivo experiments, EA pre-treatment did not affect the frequencies of MN in PCEs of bone marrow induced by DMBA. A good correlation was found between in vitro and in vivo experiments. Our results did not reveal any clear indication on the efficacy of EA on the induction of micronuclei by DMBA. EA by itself did not show any harmful effects.
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http://dx.doi.org/10.1016/j.toxlet.2013.10.012DOI Listing
January 2014

Effect of blueberries (BB) on micronuclei induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and 7,12-dimethylbenz(a)anthracene (DMBA) in mammalian cells, assessed in in vitro and in vivo assays.

Mutat Res 2013 Dec 20;758(1-2):6-11. Epub 2013 Sep 20.

Department of Ecological and Biological Sciences, Università degli Studi della Tuscia, Largo dell'Università, snc, I-01100 Viterbo, Italy.

The protective effect of blueberry (BB) on the clastogenic effects of MNNG and DMBA was evaluated with the induced micronucleus (MN) frequency as a biomarker, both in vitro and in vivo. Human hepatoma HepG2 cells, which contain most of the metabolic activating enzymes was used for the in vitro test. MN frequencies were determined in binucleated cells generated by blocking cytokinesis by use of cytochalasin-B. The MN frequency in vivo was determined in polychromatic erythrocytes (PCEs) from the bone marrow of treated mice. BB by itself was not toxic both in vivo and in vitro. There was no evidence of a potential physico-chemical interaction between BB and the test carcinogens in vitro. Pre-treatment with BB reduced the MN frequency induced by MNNG. But, simultaneous treatment and post-treatment with BB did not affect the frequency of MNNG-induced MN. BB did not affect the frequency of DMBA-induced MN in vitro under any test condition. Under in vivo conditions, BB reduced the frequencies of MNNG- and DMBA-induced MN in PCEs, but in the case of the protective effect of BB against DMBA a dramatic reduction in the percentage of PCEs was observed, suggesting increased cytotoxicity.
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http://dx.doi.org/10.1016/j.mrgentox.2013.07.012DOI Listing
December 2013

A comparative study of the anticlastogenic effects of chlorophyllin on N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) or 7,12-dimethylbenz (α) anthracene (DMBA) induced micronuclei in mammalian cells in vitro and in vivo.

Toxicol Lett 2012 Nov 15;214(3):235-42. Epub 2012 Sep 15.

Department of Ecological and Biological Sciences, Università degli Studi della Tuscia, Largo dell'Università, snc, I-01100 Viterbo, Italy.

Chlorophyllin (CHL), a water soluble derivative of chlorophyll has been shown to have both anticarcinogenic and antigenotoxic properties. We evaluated the protective effects of CHL (25μM in vitro, 4 and 100mg/kg. b.w.) on the clastogenic action of two model carcinogens, MNNG and DMBA (25μM and 2μM respectively) in vitro on human hepatoma cells (HepG2) and (40mg and 25mg/Kg/b.w. respectively) in vivo on bone marrow of mice, using the frequencies of induced micronuclei as the end point. Pre-, post- and simultaneous treatments with CHL and the carcinogen were carried out in vitro. With MNNG, only simultaneous treatment with CHL was effective in reducing the frequencies of MN, suggesting a direct interaction between CHL and MNNG. A statistically significant reduction in of DMBA induced MN was found by pre-or post treatment with CHL while a reduction (not significant) was observed by simultaneous treatment. In in vivo experiments, CHL pre-treatment did not affect the frequencies of MN in PCEs of bone marrow induced by MNNG or DMBA. However, increased the toxic effect of DMBA (reduction in percent of PCEs) was accompanied by a reduction in the induced frequencies of MN. CHL was not clastogenic in both in vitro and in vivo tests. It can be concluded that (a) CHL has a protective effect against MNNG and DMBA. This effect is dependent upon the protocol employed in in vitro experiments. In vivo, CHL did not have a protective effect against MNNG and DMBA. A protective effect of CHL against DMBA was evident only at high toxic levels.
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http://dx.doi.org/10.1016/j.toxlet.2012.08.023DOI Listing
November 2012

Protective effect of ellagic acid (EA) on micronucleus formation induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in mammalian cells, in in vitro assays and in vivo.

Mutat Res 2012 Jul 27;746(1):60-5. Epub 2012 Mar 27.

Department of Ecological and Biological Sciences, Università degli Studi della Tuscia, Largo dell'Università, Viterbo, Italy.

The beneficial effects of fruits and vegetables with respect to age-related diseases such as diabetes, atherosclerosis and several types of cancer are widely recognized and confirmed by several epidemiological studies. A possible approach for evaluating the protective potential of promising diet constituents is to evaluate their beneficial effect with respect to a set of biomarkers that are indicative of a potential risk for developing degenerative diseases. Among the numerous biomarkers of the effect of food-related carcinogens and for the assessment of the degree of risk for disease, chromosomal damage detection is very predictive. The aim of this study was to test antigenotoxic effect of ellagic acid (EA) both in in vitro and in vivo studies, in combination with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), a methylating agent. EA, a naturally occurring and widely distributed plant phenol, has been intensively studied but with conflicting results, depending on the endpoints considered and the experimental material employed. In vitro and in vivo studies differ in their experimental schedule: in the in vitro study pre- and post-treatments and simultaneous treatments with EA were performed, while in the in vivo study only pre-treatment was carried out. The results of this study clearly demonstrate a protective action of EA with respect to MNNG-induced micronuclei and cell proliferation both in vitro and in vivo. The lack of effect in the post-treatment in in vitro experiments excludes a possible effect of EA on DNA-repair systems. On the other hand, consumption of EA can have a protective action against primary DNA damage induced by oxidative stress.
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http://dx.doi.org/10.1016/j.mrgentox.2012.03.007DOI Listing
July 2012

CSA and CSB proteins interact with p53 and regulate its Mdm2-dependent ubiquitination.

Cell Cycle 2011 Nov 1;10(21):3719-30. Epub 2011 Nov 1.

Unit of Molecular Genetics of Aging, DEB, University of Tuscia, Viterbo, Italy.

Mutations in Cockayne syndrome (CS) A and B genes (CSA and CSB) result in a rare genetic disease that affects the development and homeostasis of a wide range of tissues and organs. We previously correlated the degenerative phenotype of patients to the enhanced apoptotic response, exhibited by CS cells, which is associated with the exceptional induction of p53 protein, upon a variety of stress stimuli. Here we showed that the elevated and persistent levels of p53 displayed by CS cells are due to the insufficient ubiquitination of the p53 protein. We further demonstrated that CSA and CSB proteins associate in a unique complex with p53 and Mdm2; this interaction greatly stimulates the ubiquitination of p53 in an Mdm2-dependent manner. Tandem affinity purification and immunoprecipitations combined with mass spectrometry studies indicate that CSA and CSB associate within a Cullin Ring Ubiquitin Ligase complex responsible, under certain circumstances, for p53 ubiquitination. This study identifies CSA and CSB as the key elements of a regulatory mechanism that equilibrate beneficial and detrimental effects of p53 activity upon cellular stress. The deregulation of p53, in absence of either of the CS proteins, can potentially explain the early onset degeneration of tissues and organs observed in CS patients.
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http://dx.doi.org/10.4161/cc.10.21.17905DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6245570PMC
November 2011

CSB protein is (a direct target of HIF-1 and) a critical mediator of the hypoxic response.

EMBO J 2008 Oct 11;27(19):2545-56. Epub 2008 Sep 11.

Laboratory of Molecular Cytogenetics and Mutagenesis, Department ABAC, University of Tuscia, Viterbo, Italy.

Cockayne syndrome (CS) is a rare genetic disease characterized by neurological problems, growth failure and premature ageing. Many of these features cannot simply be ascribed to the defect that CS cells display during transcription-coupled repair. Here, we show that CSB mutant cells are unable to react to hypoxic stimuli by properly activating the hypoxia-inducible factor-1 (HIF-1) pathway, a defect that is further enhanced in the event of a concomitant genotoxic stress. Furthermore, we show that CSB expression is under the control of HIF-1 and has a critical function during hypoxic response by redistributing p300 between HIF-1 and p53. Altogether, our data demonstrate that CSB is part of a feedback loop mechanism that modulates the biological functions of p53. The outcome of this study provides new insights into the understanding of the molecular basis of the CS phenotype and the involvement of the CSB protein in the hypoxic response pathway.
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http://dx.doi.org/10.1038/emboj.2008.180DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2567410PMC
October 2008

L-carnitine enhances resistance to oxidative stress by reducing DNA damage in Ataxia telangiectasia cells.

Mutat Res 2008 Feb 8;650(2):165-74. Epub 2007 Dec 8.

Department of Agrobiology and Agrochemistry, University of Tuscia, Via San Camillo de Lellis snc, Viterbo, Italy.

In this study, the modulating effect of L-carnitine on tert-butyl-hydroperoxide-induced DNA damage was compared with that of mannitol, a well known scavenger of hydroxyl radicals, both in normal and Ataxia telangiectasia mutated (ATM)-deficient lymphoblastoid cell lines established from A. telangiectasia (A-T) patients. The alkaline version of the comet assay was employed to measure the frequency of single-strand breaks (SSBs) and alkali-labile sites induced by t-butyl-OOH immediately after treatment and at different recovery times in normal and A-T cell lines, with and without pre-treatment with L-carnitine. In addition, both the yield of induced chromosomal damage and the effect on cell proliferation were evaluated. Our results show that pre-treatment of cells with L-carnitine produced an enhancement of the rate and extent of DNA repair in A-T cell lines at early recovery time; furthermore, in samples pre-treated with L-carnitine a reduction of all types of chromosomal aberration was observed, both in A-T and in wild-type cell lines. The reducing effect of L-carnitine pre-treatment on oxidative DNA damage was more prominent than that of pre-treatment with mannitol. In conclusion, we demonstrated a protective effect of L-carnitine on oxidative stress-induced DNA damage in A-T cells, suggesting its possible role in future pharmacological applications in A-T therapy.
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http://dx.doi.org/10.1016/j.mrgentox.2007.11.008DOI Listing
February 2008

DNA repair deficiency and BPDE-induced chromosomal alterations in CHO cells.

Mutat Res 2008 Jan 22;637(1-2):93-100. Epub 2007 Jul 22.

Department of Agrobiology and Agrochemistry, University of Tuscia, Via San Camillo de Lellis, 01100, Viterbo, Italy.

The induction of chromosomal aberrations and sister chromatid exchanges by BPDE was evaluated in parental and different DNA repair deficient Chinese hamster ovary cell lines in order to elucidate the mechanisms involved in their induction. These included the parental line (AA8), nucleotide excision repair (UV4, UV5, UV61), base excision repair (EM9), homologous recombination repair (Irs1SF) and non-homologous end joining (V3-3) deficient ones. The ranking of different cell lines for BPDE-induced chromosome aberrations was: UV4, Irs1SF, UV5, UV 61, EM9, V3-3, and AA8 in a descending order. Cells deficient in NER and HRR were found to be very sensitive, indicating the importance of these pathways in the repair of lesions induced by BPDE. For induction of SCEs, HRR and BER deficient cells were refractory, whereas the other cell lines responded with a dose-dependent increase. The possible mechanisms involved in BPDE-induced chromosomal alterations are discussed.
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http://dx.doi.org/10.1016/j.mrfmmm.2007.07.005DOI Listing
January 2008

Caffeine delays replication fork progression and enhances UV-induced homologous recombination in Chinese hamster cell lines.

DNA Repair (Amst) 2006 Dec 11;5(12):1449-58. Epub 2006 Sep 11.

Department of Genetics, Microbiology and Toxicology, Arrhenius Laboratories for the Natural Sciences, Stockholm University, S-106 91 Stockholm, Sweden.

The ability to bypass DNA lesions encountered during replication is important in order to maintain cell viability and avoid genomic instability. Exposure of mammalian cells to UV-irradiation induces the formation of DNA lesions that stall replication forks. In order to restore replication, different bypass mechanisms are operating, previously named post-replication repair. Translesion DNA synthesis is performed by low-fidelity polymerases, which can replicate across damaged sites. The nature of lesions and of polymerases involved influences the resulting frequency of mutations. Homologous recombination represents an alternative pathway for the rescue of stalled replication forks. Caffeine has long been recognized to influence post-replication repair, although the mechanism is not identified. Here, we found that caffeine delays the progress of replication forks in UV-irradiated Chinese hamster cells. The length of this enhanced delay was similar in wild-type cells and in cell deficient in either homologous recombination or nucleotide excision repair. Furthermore, caffeine attenuated the frequency of UV-induced mutations in the hprt gene, whereas the frequency of recombination, monitored in this same gene, was enhanced. These observations indicate that in cells exposed to UV-light, caffeine inhibits the rescue of stalled replication forks by translesion DNA synthesis, thereby causing a switch to bypass via homologous recombination. The biological consequence of the former pathway is mutations, while the latter results in chromosomal aberrations.
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http://dx.doi.org/10.1016/j.dnarep.2006.07.005DOI Listing
December 2006

Allantoin has a limited role as nitrogen source in cultured coffee cells.

J Plant Physiol 2007 May 11;164(5):544-52. Epub 2006 May 11.

Departamento de Fisiologia Vegetal, Instituto de Biologia, CP 6109, Universidade Estadual de Campinas, 13083-970 Campinas, SP, Brasil.

In plants the ureides allantoin (ALN) and allantoic acid (ALA) are formed in purine metabolism, and in some legumes both compounds play an important role as nitrogen (N) sources. In coffee plants, ALN and ALA are catabolites of caffeine degradation. Caffeine is found throughout the coffee plant and in some parts this alkaloid can accumulate up to 4% dry basis. Therefore, caffeine degradation via ureides may make an important contribution to N metabolism of the plant. Using coffee cell suspension as a model we investigated the contribution of ALN as a source of N in coffee. ALN was incorporated in the liquid medium and after 20 d of cultivation, cell mass, NO(3), NH(4), amino acids, soluble proteins, ALN and caffeine were determined in the cells. The activity of glutamine synthetase was also studied. The results showed that despite being taken up by cells ALN does not contribute significantly as a source of N in coffee cells. Compared with mineral N sources, cells grown with ALN-N accumulated much less mass. The inclusion of ALN in the medium caused significant alterations in the content of some N compounds indicating a stress condition.
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http://dx.doi.org/10.1016/j.jplph.2006.03.005DOI Listing
May 2007

The protective effect of L-carnitine in peripheral blood human lymphocytes exposed to oxidative agents.

Mutagenesis 2006 Jan 23;21(1):21-7. Epub 2005 Nov 23.

Laboratory of Molecular Cytogenetic and Mutagenesis, DABAC, Università degli Studi della Tuscia, Via S.Camillo de Lellis, I-01100 Viterbo, Italy.

Literature data indicate L-carnitine (LC), a trans-mitochondrial carrier of acetyl and long chain groups, as an agent possessing protective effects against oxidative stress in mammalian cells. However, the major factor involved in the protective mechanism is not known. The protection activity exerted by this agent against reactive oxygen species induced by hydrogen peroxide (H2O2) and t-butylhydroperoxide (t-butyl-OOH) treatment in isolated human peripheral blood lymphocytes (PBLs) has been studied. Human lymphocytes cells were isolated and pre-incubated with 5 mM LC before H2O2 (100 microM) and t-butyl-OOH (400 microM) treatment. The protective effect of LC on treated PBLs was measured by single cell gel electrophoresis and the analysis of chromosomal aberrations. Results show that lc treated cells exhibited a significant decrease in the number of oxidative induced single-strand breaks and chromosomal aberrations.
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http://dx.doi.org/10.1093/mutage/gei065DOI Listing
January 2006