Valentin-Severin I, Thybaud V, Le Bon AM, Lhuguenot JC, Chagnon MC. The autoradiographic test for unscheduled DNA synthesis: a sensitive assay for the detection of DNA repair in the HepG2 cell line.
Mutat Res 2004;
559:211-7. [PMID:
15066588 DOI:
10.1016/j.mrgentox.2003.12.007]
[Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2003] [Revised: 12/08/2003] [Accepted: 12/17/2003] [Indexed: 11/28/2022]
Abstract
We assessed the DNA-repair capacity of HepG2 cells, which were derived from a human hepatoma, by the unscheduled DNA synthesis assay, using the autoradiography protocol (UDS-AR). We evaluated DNA repair following exposure to direct mutagens (4-nitroquinoline-N-oxide (4-NQO), methyl methanesulfonate (MMS)), to mutagens requiring metabolic activation (benzo[a]pyrene (B[a]P), 2-acetylaminofluorene (2-AAF), N-dimethylnitrosoamine (NDMA)) or to structurally related non-mutagens such as pyrene and 4-acetylaminofluorene (4-AAF). All positive compounds tested induced UDS in HepG2 cells. With 4-NQO and MMS, a concentration-dependent increase in net nuclear grains per cell was observed, with 73 and 90% of cells, respectively, in repair at the highest concentration. B[a]P, 2-AAF and NDMA displayed similar dose-dependent UDS responses, but the percentage of cells in repair was lower (about 45%) than that for 4-NQO and MMS. We assessed the genotoxicity of the compounds tested by determining IC(5NNG): the concentration required to induce 5NNG. The compounds studied were ranked in order of IC(5NNG) as follows: 4-NQO = B[a]P > 2-AAF > MMS > NDMA. The UDS assay discriminated between mutagens and non-mutagens, as pyrene and 4-AAF failed to induce DNA repair. The present study demonstrates that UDS can be used as an endpoint for the detection of DNA damage in HepG2 cells.
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