Effects of 4-nitroquinoline-1-oxide on population growth, cell-cycle compartmentalization and viability in human lymphoblastoid cells.
Toxicol In Vitro 2012;
5:193-200. [PMID:
20732015 DOI:
10.1016/0887-2333(91)90017-8]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/1990] [Revised: 09/10/1990] [Indexed: 11/22/2022]
Abstract
The mechanism by which the carcinogen 4-nitroquinoline-1-oxide (4-NQO) kills mammalian cells is unclear; however, damage to DNA is presumed to be involved. We examined the relationship between the kinetics of cell death and alteration of cell-cycle compartmentalization after exposure of T5-1 human lymphoblastoid cells to 4-NQO (50 to 500 ng/ml) to establish whether cytotoxicity was related to the perturbation of DNA replication. Dose-dependent reductions in cell proliferation and cell viability were present from 1 day after treatment. Maximal reductions in viability were observed 2 days after exposure. Concentrations of 4-NQO of up to 175 ng/ml did not affect cell-cycle compartmentalization, but 250 ng 4-NQO/ml caused a transient accumulation of cells in S phase after 1 day. Only after 500 ng 4-NQO/ml was a marked and prolonged S-phase block observed from 1 day onwards. The lack of a strong correlation between S-phase block and cell death after exposure to 4-NQO suggests that responses to DNA damage in addition to perturbation of DNA replication entrain 4-NQO-induced cell lethality.
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