Genotoxiceffectsofstannouschloride(SnCl 2 )inK562cellline F.J.S.Dantas a ,J.C.P.deMattos a ,M.O.Moraes b ,M.E.Viana a ,C.A.S.Lage c , J.B.Cabral-Neto c ,A.C.Leita˜o c ,M.Bernardo-Filho a ,R.J.A.C.Bezerra a , J.J.Carvalho d ,A.Caldeira-de-Arau´jo a, * a Departamento de Biofı´sica e Biometria, IBRAG, UERJ, Avenida 28 de Setembro 87, fundos 4 o andar, Rio de Janeiro, RJ 20551-030, Brazil b Laborato ´rio de Hansenı´ase, IOC FIOCRUZ, Avenida Brasil 4365, Rio de Janeiro RJ 21045-900, Brazil c Laborato ´rio de Radiobiologia Molecular IBCCF UFRJ, Avenida Brigadeiro Trompovsky s/n Bloco G, Rio de Janeiro, RJ 21949-900, Brazil d Departamento de Histologia e Embriologia, IBRAG, UERJ, Avenida 28 de Setembro 87, fundos 3 o andar, Rio de Janeiro, RJ 20551-030, Brazil Accepted16January2002 Abstract ThetoxiceffectsofSnCl 2 inK562cellswereanalyzedinthisstudy.Thiscelllineisresistanttoreactiveoxygenspecies(ROS) making it suitable to evaluate the impact of SnCl 2 in culture either through ROS or by direct toxicity using Trypan blue dye exclusion, comet and flow cytometry assays. An important loss of viability induced by SnCl 2 in a dose–response manner was observedincellstreatedinTris-bufferedsaline(TBS).Thisnecroticcelldeathwasfurtherconfirmedbyflowcytometry.Onthe otherhand,therewasnolossofviabilitywhencellsweretreatedinrichmedium(RPMI).DNAdamagewasvisualizedinSnCl 2 - treatedK562cellsinbothtestedconditions.ThedataindicatethatSnCl 2 inducesDNAdamageandreducesK562viability.Both actionsseemtobecorrelatedwithROSformationanddirectlinkagetoDNA. # 2002PublishedbyElsevierScienceLtd. Keywords: SnCl 2 ;K562;DNAdamage;Trypanblue;Cometassay 1. Introduction Human beings have been heavily exposed to SnCl 2 presentinindustrializedfood(Saha,1997;McLeanetal., 1983). In its organic form dimethyl stannous chloride [SnCl 2 (CH 3 ) 2 ] is used in biocidal preparations (Hallas andCooney,1981). The biological effects of SnCl 2 include stimulation followedbydepressionofthecentralnervoussystemin laboratoryanimals(Gleasonetal.,1969)andincreasing dataconfirmittohavepowerfulgenotoxic(McLeanet al.,1983;OlivierandMarzin,1987),mutagenic(Singh, 1983; Triphaty et al., 1990) and carcinogenic (Ashby andTennant,1991)characteristics. The genotoxic feature of SnCl 2 is attributed to its action on DNA, since Escherichia coli repair mutants are more sensitive to it than their parental wild-type strain (Bernardo-Filho et al., 1994; Caldeira-de-Arau´jo etal.,1996).Theevaluationofitsmutageniceffectusing the E. coli supF vector indicated that reactive oxygen species(ROS)couldbeinvolved(Cabraletal.,1998),in accordance with a previously defined hypothesis estab- lished by the present group (Dantas et al., 1996). Fol- lowingthislineofevidence,wehaverecentlyshownthat SnCl 2 when used in a dose-dependent manner with O 2 brings about increasing levels of ROS, which induces DNAsingle-strandbreaks(ssb)(Dantasetal.,1999). TheK562celllinederivesfromachronicmyelogenic human leukemia (Lozzio and Lozzio, 1975). Super- expression of ROS detoxifying enzymes, mainly glu- tathione S-transferase (GST), markedly increase their resistancetoROSbypreventinglipidperoxidation(Sin- ghaletal.,1999)andapoptosis.Whenaddedtothecul- ture,anti-tumordrugscanrevertthisresistance,leading to apoptosis by modification of protein degradation pathways(Yangetal.,2001). 0278-6915/02/$-seefrontmatter # 2002PublishedbyElsevierScienceLtd. PII:S0278-6915(02)00087-X FoodandChemicalToxicology40(2002)1493–1498 www.elsevier.com/locate/foodchemtox Abbreviations: ActD, actinomycin D; DEX, dexamethasone; FBS,fetalbovineserum;GST,glutathione S-transferase;LMPA,low- meltingpointagarose;PBS,phosphatebufferedsaline;ROS,reactive oxygenspecies;TBS,Tris-bufferedsaline. * Corresponding author. Tel.: +55-21-2587-6391; fax: +55-21- 2254-3532. E-mail address: adriano@uerj.br(A.Caldeira-de-Arau´jo).