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Genotoxicity assessed by the comet and GPA assays following in vitro exposure of human lymphoblastoid cells (H9) or perinatal exposure of mother–child pairs to AZT or AZT‐3TC
Author(s) -
Escobar Patricia A.,
Olivero Ofelia A.,
Wade Nancy A.,
Abrams Elaine J.,
Nesel Carol J.,
Ness Roberta B.,
Day Richard D.,
Day Billy W.,
Meng Quanxin,
O'Neill J. Patrick,
Walker Dale M.,
Poirier Miriam C.,
Walker Ver E.,
Bigbee William L.
Publication year - 2007
Publication title -
environmental and molecular mutagenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1
H-Index - 87
eISSN - 1098-2280
pISSN - 0893-6692
DOI - 10.1002/em.20285
Subject(s) - comet assay , genotoxicity , zidovudine , cord blood , lymphoblast , dna damage , microbiology and biotechnology , virology , peripheral blood mononuclear cell , biology , in vitro , dna , virus , immunology , cell culture , medicine , genetics , toxicity , viral disease
The genotoxicity of zidovudine (AZT) based treatments was investigated in human H9 lymphoblastoid cells in an in vitro study and in red blood cells (RBCs) from perinatally exposed HIV‐1‐infected mothers and their infants in an observational cohort study. Exposure of H9 cells for 24 hr to AZT produced dose‐dependent increases in Comet assay tail moment (TM) when electrophoresed at pH 13.0, but not at pH 12.1 or pH 8.0, suggesting that DNA damage was via alkali‐labile lesions and not double‐stranded DNA strand breaks. The TM dose response at pH 13.0 correlated directly with AZT‐DNA incorporation determined by AZT‐radioimmunoassay. Levels of DNA damage in utero, measured by Comet assay TM, were similar in cord blood mononuclear cells of nucleoside analog‐exposed newborns ( n = 43) and unexposed controls ( n = 40). In contrast, the glycophorin A ( GPA ) somatic cell mutation assay (which screens for large‐scale DNA damage in RBCs) showed clear evidence that GPA N/N variants, arising from chromosome loss and duplication, somatic recombination, and gene conversion, were significantly elevated in mother–child pairs receiving prepartum AZT plus lamivudine (3TC). Cord blood from newborns exposed to AZT‐3TC had GPA N/N variant frequencies of 4.7 ± 0.7 (mean ± SE) × 10 −6 RBCs ( n = 26 infants) compared with 2.2 ± 0.3 × 10 −6 RBCs for unexposed controls ( n = 30 infants; P < 0.001). Elevations in GPA N/N variants generally persisted through 1 year of age in nucleoside analog‐exposed children. Overall, the mutagenic effects found in mother–child pairs receiving AZT‐based treatments justify their surveillance for long‐term genotoxic consequences. Environ. Mol. Mutagen., 2007. © 2007 Wiley‐Liss, Inc.