Title: Molecular basis of aflatoxin-induced mutagenesis-role of the aflatoxin B1-formamidopyrimidine adduct.

Authors: Lin, Ying-Chih; Li, Liang; Makarova, Alena V; Burgers, Peter M; Stone, Michael P; Lloyd, R Stephen

Published In Carcinogenesis, (2014 Jul)

Abstract: Aflatoxin B1 (AFB1) is a known carcinogen associated with early-onset hepatocellular carcinoma (HCC) and is thought to contribute to over half a million new HCCs per year. Although some of the fundamental risk factors are established, the molecular basis of AFB1-induced mutagenesis in primate cells has not been rigorously investigated. To gain insights into genome instability that is produced as a result of replicating DNAs containing AFB1 adducts, site-specific mutagenesis assays were used to establish the mutagenic potential of the persistent ring-opened AFB1 adduct, AFB1-formamidopyrimidine (AFB1-FAPY). This lesion was highly mutagenic, yielding replication error frequencies of 97%, with the predominant base substitution being a G to T transversion. This transversion is consistent with previous mutational data derived from aflatoxin-associated HCCs. In vitro translesion synthesis assays demonstrated that polymerase (pol) ζ was the most likely candidate polymerase that is responsible for the G to T mutations induced by this adduct.

PubMed ID: 24398669

MeSH Terms: Aflatoxin B1/adverse effects*; Animals; COS Cells; Carcinoma, Hepatocellular/chemically induced; Carcinoma, Hepatocellular/genetics*; Carcinoma, Hepatocellular/pathology; Cercopithecus aethiops; DNA Adducts/adverse effects*; DNA Replication/genetics*; DNA, Single-Stranded/genetics; Humans; Liver Neoplasms/chemically induced; Liver Neoplasms/genetics*; Liver Neoplasms/pathology; Mutagenesis, Site-Directed; Mutation/genetics*; Polymerase Chain Reaction; Pyrimidines/adverse effects*