[Show abstract][Hide abstract] ABSTRACT: BACKGROUND
Higher rates of diseases transmitted from insects to humans led to the increased use of organophosphate insecticides, proven to be harmful to human health and the environment. New, more effective chemical formulations with minimum genetic toxicity effects have become the object of intense research. These formulations include larvicides derived from plant extracts such as dillapiol, a phenylpropanoid extracted from Piper aduncum, and from microorganisms such as spinosad, formed by spinosyns A and D derived from the Saccharopolyspora spinosa fermentation process. This study investigated the genotoxicity of dillapiol and spinosad, characterising and quantifying mutation events and chromosomal and/or mitotic recombination using the somatic mutation and recombination test (SMART) in wings of Drosophila melanogaster. RESULTSStandard cross larvae (72 days old) were treated with different dillapiol and spinosad concentrations. Both compounds presented positive genetic toxicity, mainly as mitotic recombination events. Distilled water and doxorubicin were used as negative and positive controls respectively. CONCLUSION
Spinosad was 14 times more genotoxic than dillapiol, and the effect was found to be purely recombinogenic. However, more studies on the potential risks of insecticides such as spinosad and dillapiol are necessary, based on other experimental models and methodologies, to ensure safe use. (c) 2013 Society of Chemical Industry
Full-text · Article · Apr 2014 · Pest Management Science
[Show abstract][Hide abstract] ABSTRACT: In order to assess the safety of the carbon nanotubes to human health and the environment, we investigated the potential toxicity and ability of multi-walled carbon nanotubes (NT), to induce DNA damage by employing the Allium cepa genotoxicity/mutagenicity test and the Somatic Mutation and Recombination Test (SMART) in the fruitfly, Drosophila melanogaster. The results demonstrated that NT did not significantly induce genotoxic or mutagenic effects in the Allium cepa test. All concentrations evaluated in the SMART assay showed survival rates higher than 90percent, indicating the absence of chronic toxicity for NT. Furthermore, the various treatments showed no significant increase in the NT mutation and recombination frequencies in mwh/flr(3) genotype compared to respective negative controls, demonstrating the absence of DNA damage caused by NT.
Full-text · Article · Nov 2013 · Ecotoxicology and Environmental Safety
[Show abstract][Hide abstract] ABSTRACT: Ethnobotanical surveys of Cerrado native plants show that leaves of Celtis iguanaea (Jacq.) Sargent (Cannabaceae), popularly known in Brazil as "esporão de galo", are used in folk medicine for body pain, asthma, cramps, poor digestion, urinary infection, kidney dysfunctions, as well as a stimulant and diuretic. This work aimed at evaluating possible C. iguanaea aqueous leaf extract (CALE) cytotoxicity, genotoxicity, and antigenotoxicity using the mouse bone marrow micronucleous test. To assess CALE genotoxicity, Swiss mice were orally treated with three different extract concentrations (100, 300, and 500 mgkg-1). To evaluate its antigenotoxicity, the same doses were used simultaneously with a single i.p. dose of mitomycin C (MMC, 4mg.kg-1). The frequencies of micronucleated polychromatic erythrocytes (MNPCE) were evaluated 24 h and 48 h after administration except for the negative control (24 h). Genotoxicity was evaluated using the frequency of micronucleated polychromatic erythrocytes (MNPCE), whereas cytotoxicity was assessed by the polychromatic and normochromatic erythrocytes ratio (PCE/NCE). The results showed that CALE did not exhibit a significant reduction in the PCE/NCE ratio, neither a considerable increase in the frequency of MNPCE. Nonetheless, CALE reduced bone marrow toxicity (increased PCE/NCE ratio) and decreased the micronuclei frequency induced by MMC. We can conclude that CALE presented no cytotoxic and genotoxic effects, but showed antigenotoxic and anticytotoxic actions under the experimental conditions applied in this study.
Full-text · Article · Aug 2013 · Anais da Academia Brasileira de Ciências
[Show abstract][Hide abstract] ABSTRACT: Noni, a Hawaiian name for the fruit of Morinda citrifolia L., is a traditional medicinal plant from Polynesia widely used for the treatment of many diseases including arthritis, diabetes, asthma, hypertension and cancer. Here, a commercial noni juice (TNJ) was evaluated for its protective activities against the lesions induced by mitomycin C (MMC) and doxorrubicin (DXR) using the Somatic Mutation and Recombination Test (SMART) in Drosophila melanogaster. Three-day-old larvae, trans-heterozygous for two genetic markers (mwh and flr3 ), were co-treated with TNJ plus MMC or DXR. We have observed a reduction in genotoxic effects of MMC and DXR caused by the juice. TNJ provoked a marked decrease in all kinds of MMC- and DXR-induced mutant spots, mainly due to its antirecombinagenic activity. The TNJ protective effects were concentration-dependent, indicating a dose-response correlation, that can be attributed to a powerful antioxidant and/or free radical scavenger ability of TNJ.
Full-text · Article · Jun 2013 · Anais da Academia Brasileira de Ciências
[Show abstract][Hide abstract] ABSTRACT: Nucleoside reverse-transcriptase inhibitor (NRTI) drugs are a major component of highly-active antiretroviral therapy (HAART). NRTI combinations have been demonstrated as producing a sustained reduction in plasma viremia with an increased CD4 count, thereby showing clear clinical benefits. Therefore, the secondary effects caused by the combination of two NRTIs, mainly those related to amplification of genotoxic effects, due to increased risk of DNA damage caused by these drugs, should be carefully examined. We employed the standard version of the wing SMART in Drosophila melanogaster to obtain more detailed knowledge about the genotoxic profile of NRTI combinations of AZT+ddI, AZT+3TC and AZT+d4T. Our results showed that all combinations increased the frequencies of induction of mutant spots. The combinations AZT+ddI and AZT+3TC were shown to induce recombination rates ranging from 86.38% to 98.36% while AZT+d4T showed a large discrepancy between recombination and mutation percentages. The combination index demonstrated that 3TC and d4T produced antagonism while ddI showed synergistic effects in combination with AZT.
Preview · Article · Dec 2012 · Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association
[Show abstract][Hide abstract] ABSTRACT: The simultaneous treatment with the cross-linking agent cisplatin, the radiomimetic antitumoral drug bleomycin, and the anti-metabolite drug 5-fluorouracil has been used as a regimen to treat patients with squamous cell carcinoma of the head and neck. Considering that these drugs interact directly with DNA, one of the important late-occurring complications from treatment of primary malignancies is the therapy-related secondary cancers as a result of the genotoxic activity of the drugs on normal cells. In this sense, the genotoxicity of this combination was evaluated using the wing somatic mutation and recombination test in Drosophila melanogaster. The mutant spots observed in marker-heterozygous and balancer-heterozygous flies were compared in order to quantitatively and qualitatively estimate the genotoxic effect of these drugs. Cisplatin (0.003 and 0.006mM), bleomycin (0.005 and 0.01mM), and both combinations preferentially induced recombinational events, while mutation is the major event regarding the genetic toxicity of 5-fluorouracil (0.025 and 0.05mM). The combination of these drugs produced synergistic and antagonistic genotoxic effects, depending on the concentrations used, which could impose a higher risk of secondary effects associated with their genotoxic effects, emphasizing the importance of long-term monitoring in patients being treated with these drugs.
Full-text · Article · May 2012 · Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis
[Show abstract][Hide abstract] ABSTRACT: Fluoroquinolones are widely used in human and in veterinary medicine due to their broad-spectrum antibacterial activity. They act by inhibiting type II DNA topoisomerases (gyrase and topoisomerase IV). Because of the sequence homology between prokaryotic and eukaryotic topoisomerases II, fluoroquinolones can pose a hazard to eukaryotic cells. However, published information concerning the genotoxic profiles of these drugs in vivo is sparse and inconsistent. We have assessed the activities of three fluoroquinolones, ciprofloxacin, enrofloxacin and norfloxacin, in the Drosophila melanogaster Somatic Mutation and Recombination Test (SMART) and measured their mutagenic and recombinagenic potentials. Norfloxacin was non-genotoxic. Ciprofloxacin and enrofloxacin induced significant increases in spot frequencies in trans-heterozygous flies. To test the roles of somatic recombination and mutation in the observed genotoxicity, balancer-heterozygous flies were also analyzed. Ciprofloxacin and enrofloxacin were preferential inducers of homologous recombination in proliferative cells, an event linked to loss of heterozygosity.
No preview · Article · Nov 2011 · Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis
[Show abstract][Hide abstract] ABSTRACT: The somatic mutation and recombination test in Drosophila melanogaster was applied to analyze the mutagenic and recombinagenic activity of the chemotherapeutic drugs cisplatin, paclitaxel, and 5-fluorouracil, comparing the effects observed in combinatory treatments with those observed in single administrations. The results obtained in two different genotypes allowed to quantitatively and qualitatively estimate the contribution of genotoxic effects. The results obtained with the individual drug treatments showed that cisplatin and 5-fluorouracil were genotoxic, being able to increase the frequency of total spots on both genotypes. While cisplatin preferentially induced DNA damage of recombinational origin, all the damages induced by 5-fluorouracil were caused by gene and/or chromosome mutations, and the aneuploidogenic compound paclitaxel was not genotoxic. The combination of these drugs does not exert a synergist genotoxic effect in both genotypes compared to the single-agent administration. Instead, it was observed a modification in the proportion of mutation and recombination to the final genotoxicity observed. The antiproliferative activity of PAC could be responsible for the non-synergic genotoxic effect observed. Based on our results it is possible to suggest that cisplatin/paclitaxel/5-fluorouracil treatment regimen cannot impose a higher risk of the development of genotoxicity-associated secondary tumors in comparison to their individual applications.
Full-text · Article · Nov 2010 · Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association
[Show abstract][Hide abstract] ABSTRACT: This study evaluated the clastogenic and/or aneugenic potential of three nucleoside reverse transcriptase inhibitors (zidovudine - AZT, lamivudine - 3TC and stavudine - d4T) using the cytokinesis-block micronucleus (CBMN) assay in human lymphocyte cultures. All three inhibitors produced a positive response when tested in binucleated cells. The genotoxicity of AZT and 3TC was restricted to binucleated cells since there was no significant increase in the frequency of micronuclei in mononucleated cells. This finding indicated that AZT and 3TC caused chromosomal breakage and that their genotoxicity was related to a clastogenic action. In addition to the positive response observed with d4T in binucleated cells, this drug also increased the frequency of micronuclei in mononucleated cells, indicating clastogenic and aneugenic actions. Since the structural differences between AZT and 3TC and AZT and d4T involve the 3' position in the 2'-deoxyribonucleoside and in an unsaturated 2',3',dideoxyribose, respectively, we suggest that an unsaturated 2', 3', dideoxyribose is responsible for the clastogenic and aneugenic actions of d4T.
Full-text · Article · Oct 2010 · Genetics and Molecular Biology
[Show abstract][Hide abstract] ABSTRACT: The nucleoside reverse transcriptase inhibitors (NRTIs) are used in antiretroviral therapy worldwide for the treatment of HIV infections. These drugs act by blocking reverse transcriptase enzyme activity, causing pro-viral DNA chain termination. As a consequence, NRTIs could cause genomic instability and loss of heterozygosity.
This review highlights the toxic and genotoxic effects of NRTIs, particularly lamivudine (3TC) and stavudine (d4T) analogues. In addition, a battery of short-term in vitro and in vivo systems are described to explain the potential genotoxic effects of these NRTIs as a single drug or a complexity of highly active antiretroviral therapy.
The readers will gain an understanding of a secondary effect that could be induced by 3TC and d4T treatments.
Considering that AIDS has become a chronic disease, more comprehensive toxic genetic studies are needed, with particular attention to the genetic alterations induced by NRTIs. These alterations play a primary role in carcinogenesis and are also involved in secondary and subsequent steps of carcinogenesis.
No preview · Article · Apr 2010 · Expert Opinion on Drug Safety
[Show abstract][Hide abstract] ABSTRACT: Recent studies have added paclitaxel (PAC) to traditional cisplatin (CIS) regimen to treat squamous cell carcinoma of the head and neck. The target of these antineoplastic agents is nuclear DNA for CIS and microtubules for PAC, although it is not restricted to malignant cells. In this study, the genotoxicity of the combined treatment of PAC and CIS was investigated using the standard version of the wing Somatic Mutation and Recombination Test (SMART) in Drosophila melanogaster. Quantitative and qualitative genotoxic effects of these compounds were estimated by comparing wing spot frequencies in marker-heterozygous to balancer-heterozygous flies. Two different concentrations of PAC (0.0025 and 0.005mM) and CIS (0.025 and 0.05mM) as well as combinations of them were employed. The results demonstrated that the spindle poison PAC alone was not genotoxic in this test system, while CIS was able to induce a high incidence of DNA damage in both genotypes, mainly related to somatic recombination. The data obtained for the combined treatments showed that its genotoxicity varied with the concentrations used. In small concentrations the number of total spots induced by combination was reduced in relation to CIS 0.025mM just for marker-heterozygous flies, showing that somatic recombination was the prevalent event involved. At higher concentrations the combined treatment showed significant reductions in the frequencies of large single spots, for both genotypes, and twin spots for marker-heterozygous flies, but did not significantly reduce the total spots frequency in either genotype. The data suggest that aneugenic activity of PAC could be responsible for the reduction in the genotoxicity of CIS.
Full-text · Article · Feb 2010 · Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis
[Show abstract][Hide abstract] ABSTRACT: This in vivo study investigated the genotoxicity of two dental bonding agents: Adper Single Bond Plus and Prime&Bond 2.1. The somatic
mutation and recombination test (SMART) in Drosophila melanogaster was applied to analyse their genotoxicity expressed as homologous mitotic recombination, as well as point and chromosomal
mutation. SMART detects the loss of heterozygosity of marker genes expressed phenotypically on the fly's wings. This fruit
fly has extensive genetic homology to mammals, which makes it a suitable model organism for genotoxic investigations. Adper
Single Bond Plus induced statistically significant increases in the frequency of total spots at the highest concentration
tested, while Prime&Bond 2.1 was positive at all concentrations tested. The mechanistic basis underlying the genotoxicity
of Adper Single Bond Plus relies on mitotic recombination alone, and was different from that of Prime&Bond 2.1, which showed
evidence of the contribution of both recombination and mutational events. These findings indicate that both adhesives are
inducers of toxic–genetic events, with the mitotic recombination being the main mechanism of action. The clinical significance
of these observations has to be interpreted with data obtained in other bioassays.
[Show abstract][Hide abstract] ABSTRACT: Lamivudine (3TC) and stavudine (d4T) are nucleoside analogue reverse transcriptase inhibitors employed in antiretroviral therapies. The mutational and recombinational potential as well as the total genetic toxicity was determined for both compounds at concentrations allowing at least 30% survival using the standard version of wing SMART assay. The standardized clone induction frequency per mg/ml for mwh/flr(3) genotype were approximately 2 and approximately 33 mutant clones/10(5) cells/(mg/ml) for d4T and 3TC, respectively. Comparing these results with those obtained in the mwh/TM3 genotype, it was possible to quantify the recombinagenic action of each drug. Approximately 86% of the mutant clones induced by 3TC and approximately 76% of the d4T induced clones were related to their mitotic recombination action. Our results indicate that both 3TC and d4T have high recombinagenic potential, and suggest that exposure to the drugs could cause genomic instability and loss of heterozygosity. This may be due to the fact that these genetic alterations play a primary role in carcinogenesis, and are also involved in secondary and subsequent steps of carcinogenesis by which recessive oncogenic mutations are revealed.
No preview · Article · Mar 2009 · Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association
[Show abstract][Hide abstract] ABSTRACT: Antiretroviral therapies based on nucleoside reverse transcriptase inhibitors, like zidovudine (3'-azido-3'-deoxythymidine; AZT) and didanosine (2',3'-dideoxyinosine; ddI), markedly reduce human immunodeficiency virus loads. The Somatic Mutation And Recombination Test in Drosophila melanogaster (wing SMART), in its standard version, was applied to compare AZT and ddI genetic toxicity expressed as point and chromosomal mutation as well as homologous mitotic recombination. The present findings provide evidence that the mechanistic basis underlying the genetic toxicity of these antiretrovirals is mainly related to mitotic recombination. However, a genotoxic pattern can correspondingly be discerned: AZT is able to induce recombination ( approximately 85%) and mutation ( approximately 15%), and ddI causes only homologous recombination (100%) in the wing SMART assay. Another point to be considered is the fact that ddI is 3.8 times less active to induce mutant clones per mg/ml unit as compared to AZT. The clinical significance of these observations has to be interpreted in the light of data obtained from long-term toxicity in patients treated with the above mentioned agents.
No preview · Article · May 2008 · Environmental and Molecular Mutagenesis
[Show abstract][Hide abstract] ABSTRACT: In this study, the vinca alkaloids vincristine (VCR), vinblastine (VBL) and vinorelbine (VNR) were investigated for genotoxicity in the wing Somatic Mutation and Recombination Test (SMART) of Drosophila. Our in vivo experiments demonstrated that all drugs assessed induced genetic toxicity, causing increments in the incidence of mutational events, as well as in somatic recombination. Another point to be considered is the fact that VNR was able to induce, respectively, approximately 13.0 and 1.7 times more mutant clones per millimolar exposure unit as their analogues VCR and VBL. The replacement of a CH(3) attached to vindoline group in VBL by a CHO in VCR seems to be responsible for the approximately seven times higher potency of the former. In contrast, the structural modifications on VNR's catharantine group could be related to its higher genotoxic potency, as well as its similar mutagenic and recombinagenic action.
No preview · Article · Sep 2002 · Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis
[Show abstract][Hide abstract] ABSTRACT: The genotoxicity of camptothecin (CPT) and its clinical antineoplastic analogues irinotecan (CPT-11) and topotecan (TPT) were evaluated using the wing somatic mutation and recombination test (SMART) in Drosophila melanogaster. These compounds stabilize and trap the topoisomerase I-DNA complex, preventing the religation step of the breakage/rejoining reaction mediated by the enzyme. The standard version of the wing SMART was used to evaluate the three compounds and to compare the wing spots induced in marker-heterozygous and balancer-heterozygous flies. The results demonstrate that all compounds tested have a significant genotoxic effect in both genotypes analysed. At the same time, a comparison of the clone induction frequencies in marker-heterozygous and balancer-heterozygous flies shows that mitotic recombination is the prevalent mechanism through which the three compounds induce all categories of wing spots (78-93% recombination). TPT was the most genotoxic compound, probably because substitutions of amino groups for the 9-carbon of the CPT A ring leads to compounds with greater in vivo activity. CPT and CPT-11 induced, respectively, about 7 and 28 times fewer mutant clones per millimolar exposure unit than TPT.
[Show abstract][Hide abstract] ABSTRACT: Two deoxycytidine analogues, 1-beta-D-arabinofuranosylcytosine (cytosine arabinoside, citarabine, araC) and 5-aza-2'-deoxycytidine (decitabine, DAC, 5-aza-dC), are the drugs of choice in the treatment of acute myeloid leukaemia. The araC-induced cytotoxicity is a direct result of its interference with nucleic acids synthesis, whereas 5-aza-dC is a potent suppressor of DNA methylation. We employed the standard version of the wing somatic mutation and recombination test (SMART) in Drosophila melanogaster to evaluate the genotoxic potential of these two antimetabolites as a function of exposure concentration. In addition, we determined the relative contributions of mutational and recombinational events to total genotoxicity. The compounds were administered by chronic feeding of 3-day-old larvae. Our results indicate that recombinagenicity is the major genotoxic effect of araC and 5-aza-dC (approximately, 77 and 81%, respectively, recombination). The standardised clone induction frequencies (per mM concentration per cell per cell division) show that 5-aza-dC is 85 times more powerful then araC (inducing approximately 58 mutant clones per 10(5) cells per mM). The high recombinagenic activity of these two drugs suggests that--despite their therapeutic effects against cancer--a question is raised whether these drugs should be considered for adverse effects in cancer chemotherapy.
No preview · Article · Mar 2002 · Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis
[Show abstract][Hide abstract] ABSTRACT: In this study, the taxanes, paclitaxel and docetaxel were investigated for genotoxicity in the wing spot test of Drosophila melanogaster. These relatively new drugs are used in cancer therapy and show great promise in the treatment of a variety of cancers. Their major cellular target is the alpha,beta-tubulin dimer but, unlike other spindle poisons, they stabilize microtubules by a shift towards assembly, producing nonfunctional microtubule bundles. The Drosophila wing Somatic Mutation and Recombination Test (SMART) provides a rapid means to evaluate agents able to induce gene mutations and chromosome aberrations, as well as rearrangements related to mitotic recombination. We applied the standard version of SMART (with normal bioactivation) and a variant version with increased cytochrome P450-dependent biotransformation capacity. In the standard assay, docetaxel was found to be aneuploidogenic; this was effectively abolished by a high cytochrome P450-dependent detoxification capacity. This suggests, as previously reported, the involvement of this family of enzymes in the detoxification of docetaxel rather than in its activation. In contrast, paclitaxel was clearly non-genotoxic at the same (millimolar) concentrations as used for docetaxel in both crosses. The weak responsiveness of SMART assays to aneugenic compounds, the weaker ligand and assembly action of paclitaxel and the more rapid reversibility of the microtubules formed with this compound, may have caused the negative response observed in the present study.