Stannous chloride mediates single strand breaks in plasmid DNA through reactive oxygen species formation

• Published in: Toxicology letters Vol. 110; no. 3; pp. 129 - 136
• Main Authors: Dantas, Flávio J.S., Moraes, Milton O., de Mattos, José C.P., Bezerra, Roberto J.A.C., Carvalho, Elizeu F., Bernardo Filho, Mário, Caldeira de Araújo, Adriano
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 22-11-1999; Amsterdam Elsevier Science
• Subjects: Biological and medical sciences; Chemical and industrial products toxicology. Toxic occupational diseases; DNA Damage; DNA, Single-Stranded - drug effects; Dose-Response Relationship, Drug; EDTA; Hydrogen-Ion Concentration; hydroxide; Medical sciences; Metals and various inorganic compounds; Plasmids; Reactive Oxygen Species; sodium benzoate; stannous chloride; Stannous ion; tin; Tin Compounds - toxicity; Toxicology; Stannous ion; Reactive oxygen species; DNA damage; Oxidative stress; Toxicity; Escherichia coli; Tin II Chlorides; Single stranded DNA; In vitro; Free radical; Scission; Heavy metal; Dose activity relation; Bacteria; Cleavage; Mechanism of action; Enterobacteriaceae
• ISSN: 0378-4274; 1879-3169
• DOI: 10.1016/S0378-4274(99)00126-5

Stannous ion (Sn) has been employed in nuclear medicine and in food industry. We described that Stannous Chloride (SnCl
2) inactivation effect in
Escherichia coli is mediated by a Fenton-like reaction. The effect of SnCl
2 was studied through: (i) the alteration of plasmid topology in neutral and acidic pH by gel electrophoresis; and (ii) the transformation efficiency of an wild type
E. coli strain. Treatment of plasmid DNA pUC 9.1 with SnCl
2, at pH 7.4, results in DNA single-strand breaks (SSB), in a dose-dependent manner. Addition of sodium benzoate partly inhibited the DNA damage, while EDTA completely abolishes DNA-SSB. Furthermore, the ability of the plasmid to transform
E. coli was reduced. At pH 1.3, SnCl
2 exerts a protective effect on plasmid against HCl depurination. Our results suggest the generation of ROS, such as
OH by a Fenton-like reaction, close to the site of the lesions due to a possible complexation of stannous ion to DNA.