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1.
EFSA J ; 21(11): e08365, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38027427

RESUMO

The EFSA Panel on Food Additives and Flavourings (FAF) was requested to evaluate the safety of the smoke flavouring Primary Product Smoke Concentrate 809045 (SF-003), for which a renewal application was submitted in accordance with Article 12(1) of Regulation (EC) No 2065/2003. This opinion refers to the assessment of data submitted on chemical characterisation, dietary exposure and genotoxicity of the Primary Product. Product Smoke Concentrate 809045 is obtained by pyrolysis of beech wood. The Panel concluded that the compositional data provided on the Primary Product are adequate. At the maximum proposed use levels, dietary exposure estimates calculated with DietEx ranged from 0.1 to 1.5 mg/kg body weight (bw) per day at the mean and from 0.2 to 5.2 mg/kg bw per day at the 95th percentile. The Panel concluded that eleven components in the Primary Product raise a potential concern for genotoxicity. In addition, a potential concern for genotoxicity was identified for the unidentified part of the mixture. The Primary Product contains furan-2(5H)-one and benzene-1,2-diol, for which a concern for genotoxicity was identified in vivo upon oral administration. Considering that the exposure estimates for these two components are above the threshold of toxicological concern (TTC) of 0.0025 µg/kg bw per day for DNA-reactive mutagens and/or carcinogens, the Panel concluded that the Primary Product raises concern with respect to genotoxicity.

2.
EFSA J ; 21(11): e08364, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38027431

RESUMO

The EFSA Panel on Food Additives and Flavourings (FAF) was requested to evaluate the safety of the smoke flavouring Primary Product Zesti Smoke Code 10 (SF-002), for which a renewal application was submitted in accordance with Article 12(1) of Regulation (EC) No 2065/2003. This opinion refers to the assessment of data submitted on chemical characterisation, dietary exposure and genotoxicity of the Primary Product. Zesti Smoke Code 10 is obtained by pyrolysis of hickory and oak woods. Given the limitations of the quantification approach employed by the applicant, the Panel could not judge whether the applied methods meet the legal quality criterion that at least 80% of the volatile fraction shall be identified and quantified. At the maximum proposed use levels, dietary exposure estimates calculated with DietEx ranged from 0.02 to 4.6 mg/kg body weight (bw) per day at the mean and from no dietary exposure to 13.0 mg/kg bw per day at the 95th percentile. The Panel concluded that four components in the Primary Product raise a potential concern for genotoxicity. In addition, a potential concern for genotoxicity was identified for the unidentified part of the mixture. The Primary Product contains furan-2(5H)-one and benzene-1,2-diol, for which a concern for genotoxicity was identified in vivo upon oral administration. Considering that the exposure estimates for these two components are above the threshold of toxicological concern (TTC) of 0.0025 µg/kg bw per day for DNA-reactive mutagens and/or carcinogens, the Panel concluded that the Primary Product raises concern with respect to genotoxicity.

3.
EFSA J ; 21(11): e08366, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38027432

RESUMO

The EFSA Panel on Food Additives and Flavourings (FAF) was requested to evaluate the safety of the smoke flavouring Primary Product Scansmoke SEF7525 (SF-004), for which a renewal application was submitted in accordance with Article 12(1) of Regulation (EC) No 2065/2003. This opinion refers to the assessment of data submitted on chemical characterisation, dietary exposure and genotoxicity of the Primary Product. Scansmoke SEF7525 is obtained from a tar produced from a mixture of red oak, white oak, maple, beech and hickory. Based on the compositional data, the Panel noted that the identified and quantified proportion of the solvent-free fraction amounts to 32.6 weight (wt)%, thus the applied method does not meet the legal quality criterion that at least 50% of the solvent-free fraction shall be identified and quantified. At the maximum proposed use levels, dietary exposure estimates calculated with Food Additive Intake Model (FAIM) ranged from 0.6 to 3.8 mg/kg body weight (bw) per day at the mean and from 1.1 to 10.1 mg/kg bw per day at the 95th percentile. Based on the available information on genotoxicity on 44 identified components, the Panel concluded that two substances in the Primary Product, styrene and benzofuran, raise a potential concern for genotoxicity. In addition, a potential concern for genotoxicity was identified for the unidentified part of the mixture. Considering that the exposure estimates for styrene and benzofuran are above the threshold of toxicological concern (TTC) value of 0.0025 kg/kg bw per day for DNA-reactive mutagens and/or carcinogens and since further data are needed to clarify their potential genotoxicity, the Panel concluded that the potential safety concern for genotoxicity of the Primary Product cannot be ruled out.

4.
EFSA J ; 21(11): e08370, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38027436

RESUMO

The EFSA Panel on Food Additives and Flavourings (FAF) was requested to evaluate the safety of the smoke flavouring Primary Product Fumokomp (SF-009), for which a renewal application was submitted in accordance with Article 12(1) of Regulation (EC) No 2065/2003 (in the renewal application the Primary Product is reported as 'Fumokomp Conc.'). This opinion refers to an assessment of data submitted on chemical characterisation, dietary exposure and genotoxicity of the Primary Product. Fumokomp Conc. is produced by pyrolysis of beech and hornbeam woods. Gas chromatography-mass spectrometry (GC-MS) was applied for both identification and quantification of the volatile constituents of the Primary Product. Given the limitations of the method, the Panel cannot judge with confidence whether the applied method meets the legal quality criterion that at least 80% of the volatile fraction shall be identified and quantified. Moreover, the Panel concluded that the absence of furan-2(5H)-one from the Primary Product was not convincingly demonstrated. At the maximum proposed use levels, dietary exposure estimates calculated with FAIM ranged from 0.04 to 0.9 mg/kg body weight (bw) per day at the mean and from 0.1 to 1.5 mg/kg bw per day at the 95th percentile. The information available on the 32 identified components of the Primary Product, although limited, did not indicate a concern for genotoxicity for any of these substances. However, whole mixture testing in an in vitro mouse lymphoma assay gave positive results which would require an adequate in vivo follow-up study. In addition, the potential for aneugenicity of the Primary Product has not been adequately investigated. Accordingly, the potential safety concern for genotoxicity of the Primary Product cannot be ruled out.

5.
EFSA J ; 21(11): e08367, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38027441

RESUMO

The EFSA Panel on Food Additives and Flavourings (FAF) was requested to evaluate the safety of the smoke flavouring Primary Product SmoKEz C-10 (SF-005), for which a renewal application was submitted in accordance with Article 12(1) of Regulation (EC) No 2065/2003. This opinion refers to the assessment of data submitted on chemical characterisation, dietary exposure and genotoxicity of the Primary Product. SmoKEz C-10 is obtained by pyrolysis of maple, oak, hickory, ash, birch, beech and cherry woods. Given the limitations of the quantification approach employed by the applicant, the Panel could not judge whether the applied methods meet the legal quality criterion that at least 80% of the volatile fraction shall be identified and quantified. At the maximum proposed use levels, dietary exposure estimates calculated with DietEx ranged from 0.01 to 5.1 mg/kg body weight (bw) per day at the mean and from no dietary exposure to 18.1 mg/kg bw per day at the 95th percentile. The Panel concluded that five components in the Primary Product raise a potential concern for genotoxicity. In addition, a potential concern for genotoxicity was identified for the unidentified part of the mixture. The Primary Product contains furan-2(5H)-one and benzene-1,2-diol, for which a concern for genotoxicity was identified in vivo upon oral administration. Considering that the exposure estimates for these two components are above the threshold of toxicological concern (TTC) of 0.0025 µg/kg bw per day for DNA-reactive mutagens and/or carcinogens, the Panel concluded that the Primary Product raises concern with respect to genotoxicity.

6.
EFSA J ; 21(11): e08363, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38027451

RESUMO

The EFSA Panel on Food Additives and Flavourings (FAF) was requested to evaluate the safety of the smoke flavouring Primary Product proFagus Smoke R714 (SF-001), for which a renewal application was submitted in accordance with Article 12(1) of Regulation (EC) No 2065/2003. This opinion refers to the assessment of data submitted on chemical characterisation, dietary exposure and genotoxicity of the Primary Product. ProFagus Smoke R714 is obtained by pyrolysis of beech and oak woods as main source materials. Based on the compositional data, the Panel noted that the identified and quantified proportion of the solvent-free fraction amounts to 39 weight (wt)%, thus the applied method does not meet the legal quality criterion that at least 50% of the solvent-free fraction shall be identified and quantified. At the maximum proposed use levels, dietary exposure estimates calculated with DietEx ranged from 0.7 to 10.9 mg/kg body weight (bw) per day at the mean and from 2.2 to 42.5 mg/kg bw per day at the 95th percentile. The Panel concluded that three components in the Primary Product raise a potential concern for genotoxicity. In addition, a potential concern for genotoxicity was identified for the unidentified part of the mixture. The Primary Product contains furan-2(5H)-one, for which a concern for genotoxicity was identified in vivo upon oral administration. Considering that the exposure estimates for this component are above the threshold of toxicological concern (TTC) of 0.0025 µg/kg bw per day for DNA-reactive mutagens and/or carcinogens, the Panel concluded that the Primary Product raises concern with respect to genotoxicity.

7.
EFSA J ; 21(11): e08368, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38027452

RESUMO

The EFSA Panel on Food Additives and Flavourings (FAF) was requested to evaluate the safety of the smoke flavouring Primary Product SmokEz Enviro-23 (SF-006), for which a renewal application was submitted in accordance with Article 12(1) of Regulation (EC) No 2065/2003. This opinion refers to the assessment of data submitted on chemical characterisation, dietary exposure and genotoxicity of the Primary Product. SmokEz Enviro-23 is obtained by pyrolysis of oak, maple, hickory, ash, birch, beech and cherry woods. Given the limitations of the quantification approach employed by the applicant, the Panel could not judge whether the applied methods meet the legal quality criterion that at least 80% of the volatile fraction shall be identified and quantified. At the maximum proposed use levels, dietary exposure estimates calculated with DietEx ranged from 0.01 to 3.2 mg/kg body weight (bw) per day at the mean and from no dietary exposure to 9.5 mg/kg bw per day at the 95th percentile. The Panel concluded that four components in the Primary Product raise a potential concern for genotoxicity. In addition, a potential concern for genotoxicity was identified for the unidentified part of the mixture. The Primary Product contains furan-2(5H)-one and benzene-1,2-diol, for which a concern for genotoxicity was identified in vivo upon oral administration. Considering that the exposure estimates for these two components are above the threshold of toxicological concern (TTC) of 0.0025 µg/kg bw per day for DNA-reactive mutagens and/or carcinogens, the Panel concluded that the Primary Product raises concern with respect to genotoxicity.

8.
EFSA J ; 21(11): e08369, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38027454

RESUMO

The EFSA Panel on Food Additives and Flavourings (FAF) was requested to evaluate the safety of the smoke flavouring Primary Product proFagus Smoke R709 (SF-008), for which a renewal application was submitted in accordance with Article 12(1) of Regulation (EC) No 2065/2003. This opinion refers to the assessment of data submitted on chemical characterisation, dietary exposure and genotoxicity of the Primary Product. ProFagus Smoke R709 is obtained by pyrolysis of beech and oak wood as main source materials. The panel concluded that the compositional data provided on the Primary Product are adequate. At the maximum proposed use levels, dietary exposure estimates calculated with DietEx ranged from 0.8 to 12.2 mg/kg body weight (bw) per day at the mean and from 2.3 to 51.4 mg/kg bw per day at the 95th percentile. The Panel concluded that three components in the Primary Product raise a potential concern for genotoxicity. In addition, a potential concern for genotoxicity was identified for the unidentified part of the mixture. The Primary Product contains furan-2(5H)-one, for which a concern for genotoxicity was identified in vivo upon oral administration. Considering that the exposure estimates for this component are above the TTC of 0.0025 µg/kg bw per day for DNA-reactive mutagens and/or carcinogens, the panel concluded that the Primary Product raises concern with respect to genotoxicity.

9.
EFSA J ; 20(5): e07299, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35646165

RESUMO

The EFSA Panel on Food Additives and Flavourings (FAF) was requested to evaluate the safety of Prosmoke BW 01 as a new smoke flavouring primary product, in accordance with Regulation (EC) No 2065/2003. Prosmoke BW01 is produced by pyrolysis of beechwood (Fagus sylvatica L.) sawdust. Its water content is estimated at 56 wt%, the total identified volatile fraction accounts for 28 wt% of the primary product, corresponding to 64% of the solvent-free mass, while the unidentified fraction amounts to 16 wt% of the primary product. Analytical data provided for three batches demonstrated that their batch-to-batch-variability was sufficiently low. However, for the batch used for the toxicological studies, there were substantial deviations in the concentration of nearly all the constituents compared to the other three batches. The dietary exposure of Prosmoke BW 01 was estimated to be between 6.2 and 9.2 mg/kg body weight (bw) per day, respectively, using SMK-EPIC and SMK-TAMDI. Using the FAIM tool, the 95th percentile exposure estimates ranged from 3.2 mg/kg bw per day for the elderly to 17.9 mg/kg bw per day for children. The Panel noted that furan-2(5H)-one is present in all batches of the primary product at an average concentration of 0.88 wt%. This substance was evaluated by the FAF Panel as genotoxic in vivo after oral exposure. The Panel considered that the (geno)toxicity studies available on the whole mixture were not adequate to support the safety assessment, due to limitations in these studies and because they were performed with a batch which may not be representative for the material of commerce. Considering that the exposure estimates for furan-2(5H)-one are above the TTC value of 0.0025 µg/kg bw per day (or 0.15 µg/person per day) for DNA-reactive mutagens and/or carcinogens, the Panel concluded that Prosmoke BW 01 raises a concern with respect to genotoxicity.

10.
EFSA J ; 19(5): e06585, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33976718

RESUMO

The present opinion deals with an updated safety assessment of the food additive titanium dioxide (E 171) based on new relevant scientific evidence considered by the Panel to be reliable, including data obtained with TiO2 nanoparticles (NPs) and data from an extended one-generation reproductive toxicity (EOGRT) study. Less than 50% of constituent particles by number in E 171 have a minimum external dimension < 100 nm. In addition, the Panel noted that constituent particles < 30 nm amounted to less than 1% of particles by number. The Panel therefore considered that studies with TiO2 NPs < 30 nm were of limited relevance to the safety assessment of E 171. The Panel concluded that although gastrointestinal absorption of TiO2 particles is low, they may accumulate in the body. Studies on general and organ toxicity did not indicate adverse effects with either E 171 up to a dose of 1,000 mg/kg body weight (bw) per day or with TiO2 NPs (> 30 nm) up to the highest dose tested of 100 mg/kg bw per day. No effects on reproductive and developmental toxicity were observed up to a dose of 1,000 mg E 171/kg bw per day, the highest dose tested in the EOGRT study. However, observations of potential immunotoxicity and inflammation with E 171 and potential neurotoxicity with TiO2 NPs, together with the potential induction of aberrant crypt foci with E 171, may indicate adverse effects. With respect to genotoxicity, the Panel concluded that TiO2 particles have the potential to induce DNA strand breaks and chromosomal damage, but not gene mutations. No clear correlation was observed between the physico-chemical properties of TiO2 particles and the outcome of either in vitro or in vivo genotoxicity assays. A concern for genotoxicity of TiO2 particles that may be present in E 171 could therefore not be ruled out. Several modes of action for the genotoxicity may operate in parallel and the relative contributions of different molecular mechanisms elicited by TiO2 particles are not known. There was uncertainty as to whether a threshold mode of action could be assumed. In addition, a cut-off value for TiO2 particle size with respect to genotoxicity could not be identified. No appropriately designed study was available to investigate the potential carcinogenic effects of TiO2 NPs. Based on all the evidence available, a concern for genotoxicity could not be ruled out, and given the many uncertainties, the Panel concluded that E 171 can no longer be considered as safe when used as a food additive.

11.
EFSA J ; 18(10): e06247, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33133270

RESUMO

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) was requested by the European Commission to re-evaluate the safety of styrene (FCM No 193) for use in plastic food contact materials (FCM) following the classification by the International Agency for Research on Cancer (IARC) as 'probably carcinogenic to humans'. The IARC Monograph pertains to hazard identification, based on studies on high-dose occupational exposures by inhalation and animal studies, also mainly by inhalation. The Panel considered that the IARC conclusions cannot be directly applied to the evaluation of risks for consumers from the oral exposure to styrene, but also concluded that, based on the data provided in the IARC Monograph and by the industry, a concern for genotoxicity associated with oral exposure to styrene cannot be excluded. The migration of styrene into foods packed in styrenic plastics is below 10 µg/kg for the majority of the foods, but up to 230 µg/kg was reported. Migration tends to be high for contact with fatty foods, and/or with high surface to volume ratios of the FCM. Dietary exposure of the consumers to styrene migrating from styrenic plastics was estimated in the order of 0.1 µg/kg body weight (bw) per day. It is in the same range as exposure from styrene present in foods as such. The dietary exposure (food component plus migration from styrenic plastics) is similar or lower than that by inhalation in the general population. Taking the human exposure data into account, the Panel concluded that a systematic review of genotoxicity and mechanistic data, comparative toxicokinetics and analysis of species differences is required for assessing the safety of styrene for its use in FCM.

12.
EFSA J ; 15(11): e05012, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32625331

RESUMO

The EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF Panel) was requested by the European Commission according to Art. 29 1(a) of the Regulation (EC) No 178/2002 to carry out a review of existing literature on the safety of ethyl acrylate [FL-no: 09.037] when used as a flavouring substance. Ethyl acrylate [FL-no: 09.037] was evaluated in 2010 by EFSA in FGE.71 as a flavouring substance, based on the 2006 JECFA evaluation. The Panel concluded that ethyl acrylate was of no safety concern at estimated level of intake as flavouring substance based on the Maximised Survey-Derived Daily Intake (MSDI) approach. The Panel has evaluated the new literature available and any previous assessments performed by JECFA (2006) and EFSA (2010). Moreover, new data on the use levels of ethyl acrylate as flavouring substance have been provided. For use as flavouring substance, the chronic dietary exposure estimated using the added portions exposure technique (APET), is calculated to be 3,545 µg/person per day for a 60-kg adult and 2,233 µg/person per day for a 15-kg 3-year-old child. Exposure from food contact materials may be up to 6,000 µg/person per day. The Panel considered that based on the available data, which covers all relevant genetic endpoints (i.e. gene mutations, structural and numerical chromosomal aberrations) there is no concern with respect to genotoxicity of ethyl acrylate. The Panel evaluated the available carcinogenicity studies conducted in rats and mice and agreed with the NTP evaluation (1998) concluding that the forestomach squamous cell papilloma and carcinoma observed in rodents were not relevant to humans. Additionally, there was no evidence of systemic toxicity in short-term and subchronic toxicity studies. Therefore, the Panel concluded that there is no safety concern for the use of ethyl acrylate as a flavouring substance, under the intended conditions of use.

13.
EFSA J ; 15(11): e05013, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32625332

RESUMO

Benzophenone [FL-no: 07.032] has been evaluated as a flavouring substance, in FGE.69, by the EFSA Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food in 2008. Benzophenone was evaluated also by JECFA (2011) and by IARC (2013) based on studies that were not considered in the EFSA opinion on FGE.69. Therefore, the Commission requested the CEF Panel to carry out a review of existing literature on the safety of this flavouring substance. In the framework of the evaluation of benzophenone as a food contact material, the CEF Panel established a tolerable daily intake (TDI) of 0.03 mg/kg body weight (bw) per day (2009). In the present Opinion, the Panel considered the already existing evaluations by EFSA, JECFA, IARC and available literature data on benzophenone toxicity. Moreover, new data on the use levels of benzophenone as a flavouring substance have been provided. The Panel considers that there is no concern with respect to genotoxicity. The Panel considers the endocrine activities of benzophenone and its metabolite 4-hydroxybenzophenone as weak and not directly related to the observed toxic effects including the neoplastic effects in rodents. The Panel confirms that the conservative approach taken by EFSA (2009) to derive a TDI of 0.03 mg/kg bw for benzophenone is appropriate to cover the non-neoplastic effects in the chronic toxicity studies and the neoplastic effects induced in the rodent carcinogenicity studies. The TDI is in the same order of magnitude as the chronic dietary exposure of adults and children to benzophenone (10-20 µg/kg bw per day) for the amount of added flavouring substance. The Panel considers that the calculated TDI and exposure estimate are based on conservative assumptions. The Panel concludes that there is no safety concern for benzophenone under the current condition of use as a flavouring substance.

14.
Toxicology ; 260(1-3): 132-41, 2009 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-19464579

RESUMO

Inorganic arsenic (iAs) is a human carcinogen, well known as a clastogenic compound. To evaluate the molecular mechanism of arsenite (iAs(III)) toxicity, we investigated the effects on cell growth and apoptosis, telomere length, telomerase expression, as well as the formation of reactive oxygen species (ROS) in male and female human cord blood cells in vitro. Incubation with iAs(III) at the concentration of 0.0001 microM increased telomerase mRNA and protein expression maintained both telomere length and cellular growth, and induced mRNA over-expression of the two oncogenes ras and myc. Our results suggest that female cord blood cells are more sensitive than male ones to iAs(III) induced telomerase stimulation at low concentrations, possibly related to the increased expression of ras and myc oncogenes. On the contrary, at the concentration of 1 microM, iAs(III) decreased telomerase expression and telomere length, and induced apoptosis, necrosis and production of reactive oxygen species. Buthionine sulfoximine (BSO), an inhibitor of glutathione (GSH) synthesis, markedly increased the percentage of apoptotic cells, suggesting that GSH is fundamental for detoxification of iAs(III) in cord blood cells. The reactive oxygen species (ROS) scavenger, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), protected cord blood cells from iAs(III) toxicity, and prevented telomere shortening and telomerase down-modulation. It can be concluded that telomerase expression and telomere length are associated with iAs(III) induced cell death, via production of reactive oxygen species, as well as with iAs(III) induced effects on cell differentiation processes and rate of cell growth.


Assuntos
Arsenitos/toxicidade , Sangue Fetal/efeitos dos fármacos , Compostos de Sódio/toxicidade , Telomerase/biossíntese , Telômero/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Western Blotting , Butionina Sulfoximina/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Óxidos N-Cíclicos/farmacologia , Indução Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Feminino , Sangue Fetal/enzimologia , Citometria de Fluxo , Sequestradores de Radicais Livres/farmacologia , Glutationa/metabolismo , Humanos , Masculino , Proteínas Proto-Oncogênicas c-myc/biossíntese , Proteínas Proto-Oncogênicas c-myc/genética , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Espécies Reativas de Oxigênio/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores Sexuais , Células-Tronco/efeitos dos fármacos , Células-Tronco/enzimologia , Telomerase/genética , Telômero/metabolismo , Proteínas ras/biossíntese , Proteínas ras/genética
15.
J Appl Toxicol ; 26(4): 317-25, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16705669

RESUMO

Styrene is one of the most important monomers produced worldwide. IARC classified styrene as a possible carcinogen to humans (group 2B). Styrene-7,8-oxide (SO) is the main reactive metabolite of styrene, and it is found to be genotoxic in several in vitro test systems. Styrene and styrene-7,8-oxide (SO) toxicity to HepG2 cells was investigated by evaluating end-points such as heat shock proteins (Hsps), metallothioneins (MT), apoptosis-related proteins, accumulation of styrene within the cells and expression of two isoforms of cytochrome P450. The potential activity of styrene and styrene-7,8-oxide in modulating gene expression was also investigated. The results showed induction of Hsp70, metallothioneins, BclX(S/L) and c-myc expression and a decrease in Bax expression in HepG2 after treatments, confirming that these compounds activated protective mechanisms. Moreover, up-regulation of TGFbeta2 and TGFbetaRIII in HepG2 cells was found after exposure to styrene, while in human primary hepatocytes these genes were down-regulated after both treatments. Finally, it was found that styrene and SO treatments did not induce CYP1A2 and CYP2E1 protein expression. In conclusion, both compounds caused toxic stress in HepG2 cells, with SO being more toxic; in the meantime, a different effect of the two compounds in HepG2 cells and primary human hepatocytes was observed regarding their activity in gene modulation.


Assuntos
Carcinógenos/toxicidade , Compostos de Epóxi/toxicidade , Hepatócitos/efeitos dos fármacos , Estireno/toxicidade , Carcinógenos/metabolismo , Carcinoma Hepatocelular , Linhagem Celular Tumoral , Citocromo P-450 CYP1A2/metabolismo , Citocromo P-450 CYP2E1/metabolismo , Ensaio de Imunoadsorção Enzimática , Compostos de Epóxi/metabolismo , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica , Proteínas de Choque Térmico HSP70/metabolismo , Hepatócitos/enzimologia , Humanos , Metalotioneína/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase , Proteoglicanas/genética , Proteoglicanas/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , RNA Mensageiro/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/genética , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Estireno/metabolismo , Fator de Crescimento Transformador beta2/genética , Fator de Crescimento Transformador beta2/metabolismo , Proteína bcl-X/metabolismo
16.
J Neurooncol ; 67(1-2): 65-73, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15072449

RESUMO

The main dose-limiting side effect of cancer treatment with platinum compounds is peripheral neurotoxicity. To investigate the intracellular mechanisms of platinum drugs neurotoxicity we have studied the effects of cisplatin and oxaliplatin on the human neuroblastoma cell line SH-SY5Y. Both platinum compounds are toxic causing cellular death by inducing apoptosis but oxaliplatin is less neurotoxic than cisplatin. The study of the proteins involved in the intracellular transduction pathways that may cause apoptotic death, revealed a very similar pattern of changes after exposure to cisplatin or oxaliplatin. In particular, as demonstrated by densitometric analysis, after exposure to both platinum compounds the total amount of the anti-apoptotic protein Bcl-2 was significantly reduced. Conversely, the amount of the pro-apoptotic protein p53 significantly increased. Caspases 3 and 7 were activated, but their activation was a late event, indicating a secondary role in the apoptotic process. Among the mitogen activated protein kinases, only the p38 protein was activated (phosphorylated) early enough to have a possible role in inducing apoptosis, possibly through p53 stabilization. The results of the present study and the data of the literature demonstrate that the ways in which cisplatin and oxaliplatin are neurotoxic are very similar and include not only DNA damage, but also the modulation of specific molecules involved in regulating the cellular equilibrium between apoptotic death and the cell cycle.


Assuntos
Antineoplásicos/toxicidade , Apoptose/efeitos dos fármacos , Cisplatino/toxicidade , Neuroblastoma/tratamento farmacológico , Compostos Organoplatínicos/toxicidade , Caspase 3 , Caspase 7 , Caspases/efeitos dos fármacos , Linhagem Celular Tumoral , Ativação Enzimática/efeitos dos fármacos , Humanos , Immunoblotting , Marcação In Situ das Extremidades Cortadas , Oxaliplatina , Proteínas Proto-Oncogênicas c-bcl-2/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Proteína Supressora de Tumor p53/efeitos dos fármacos
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