Influence of TEGDMA on the mammalian cell cycle in comparison with chemotherapeutic agents

Abstract

Objectives The dental resin monomer triethylene glycol dimethacrylate (TEGDMA) caused a cell cycle arrest in response to DNA damage. However, the underlying mechanisms are unclear. Therefore, the influence of TEGDMA on the cell cycle was analyzed in comparison with the chemotherapeutic agents adriamycin and mitomycin C (MMC), which arrest the cell cycle through different mechanisms. Methods RAW264.7 mouse macrophages were exposed to TEGDMA, adriamycin, or MMC, and flow cytometry (FACS) was used for cell cycle analyses. In addition, the number of surviving cells was determined by a crystal violet assay, and viability in treated cultures was determined by FACS after staining of cells with trypan blue. Morphological changes in cells were interpreted using forward and side scatter (FSC/SSC) cell physical criteria. Results The exposure of cells to 1 mM TEGDMA resulted in a delay of the cell cycle in G1 phase since 85.3% of the cells were found in G1 compared with 47.4% in untreated controls. Adriamycin also increased the number of cells (72.1%) in G1 compared to controls. Caffeine, an inhibitor of the checkpoint kinases ATM (ataxia telangiectasia-mutated) and ATR (ATM and Rad3-related), had no effect on the TEGDMA and adriamycin-induced cell cycle arrest. In contrast, MMC delayed the cell cycle in G2 since cell numbers increased to 22.1% compared to 10.7% in controls. The effect of MMC on G2 was even increased by low caffeine concentrations (100–400 μM), but 1000 μM caffeine inhibited MMC activity. Significance Our results suggest that the mechanism of a TEGDMA-induced arrest of the cell cycle is different from the effect of the direct-acting interstrand crosslinking agent MMC. Since TEGDMA produced oxidative stress, it probably acts indirectly on the cell cycle through reactive oxygen species, unless TEGDMA–DNA adducts are shown experimentally.