Sensitivity of different endpoints for in vitro measurement of genotoxicity of extractable organic matter associated with ambient airborne particles (PM10).
Sensitivity and correlations among three endpoints were evaluated to assess the genotoxic potential of organic complex mixtures in vitro. This study was focused on DNA adduct formation, DNA single strand break induction and tumour suppressor p53 protein up-regulation produced by extractable organic matter (EOM) absorbed on respirable particulate matter PM(10) (particulate matter<10microm) collected in three European cities (Prague, Sofia, Kosice) during winter and summer period. To compare the sensitivity of particular endpoints for in vitro measurement of complex mixture genotoxicity, the metabolically competent human hepatoma cell line Hep G2 was treated with equivalent EOM concentration of 50microg/ml. Cell exposure to EOMs resulted in significant DNA adduct formation and DNA strand break induction, however, a lack of protein p53 up-regulation over the steady-state level was found. While the maximum of DNA strand breaks was determined after 2h cell exposure to EOMs, 24h treatment interval was optimal for DNA adduct determination. No substantial location- and season-related differences in EOM genotoxicity were detected using DNA strand break assessment. In agreement with these results no significant variation in DNA adduct levels were found in relation to the locality and season except for the monitoring site in Prague. The Prague EOM sample collected during summer period produced nearly three-fold lower DNA adduct level in comparison to the winter EOM sample. Comparable results were obtained when the ambient air genotoxicity, based on the concentration of carcinogenic PAHs in cubic meter of air (ng c-PAHs/m(3)), was elicited using either DNA adduct or strand break determination. In general, at least six-fold higher genotoxicity of the winter air in comparison to the summer air was estimated by each particular endpoint. Moreover, the genotoxic potential of winter air revealed by DNA adduct assessment and DNA strand break measurement increased in the same order: Kosice<<Prague<Sofia. Based on these data we suppose that two endpoints DNA breakage and DNA adduction are sensitive in vitro biomarkers for estimation of genotoxic activity of organic complex mixture associated with airborne particles. On the other hand, the measurement of protein p53 up-regulation manifested some limitations; therefore it cannot be used as a reliable endpoint for in vitro genotoxicity assessment.
Gábelová
Alena
A
Laboratory of Mutagenesis and Carcinogenesis, Cancer Research Institute SAS, Bratislava, Slovakia. alena.gabelova@savba.sk
Valovicová
Zuzana
Z
Bacová
Gabriela
G
Lábaj
Juraj
J
Binková
Blanka
B
Topinka
Jan
J
Sevastyanova
Oksana
O
Srám
Radim J
RJ
Kalina
Ivan
I
Habalová
Viera
V
Popov
Todor A
TA
Panev
Teodor
T
Farmer
Peter B
PB
D000393:Air Pollutants / Q000633:toxicity*; D002274:Carcinogens, Environmental / Q000633:toxicity*; D045744:Cell Line, Tumor; D020552:Comet Assay; D018736:DNA Adducts / Q000032:analysis; D004249:DNA Damage; D006801:Humans; D009152:Mutagenicity Tests / Q000379:methods*; D009930:Organic Chemicals / Q000633:toxicity; D052638:Particulate Matter / Q000633:toxicity*; D011084:Polycyclic Aromatic Hydrocarbons / Q000633:toxicity*; D012680:Sensitivity and Specificity; D016159:Tumor Suppressor Protein p53 / Q000032:analysis
D000393:Air Pollutants; D002274:Carcinogens, Environmental; D018736:DNA Adducts; D009930:Organic Chemicals; D052638:Particulate Matter; D011084:Polycyclic Aromatic Hydrocarbons; D016159:Tumor Suppressor Protein p53