Institute of Environmental Systems Biology, Dalian Maritime University, Linghai Road 1, Dalian, 116026, PR China.
Environ Pollut. 2018 Jul;238:1048-1055. doi: 10.1016/j.envpol.2018.03.044. Epub 2018 Apr 26.
Exposure to pesticides results in DNA damage and genomic instability. We previously predicted that endosulfan might be associated with leukemia, but the role of endosulfan in leukemia cells has been unexplored. The aim of this study is to elucidate molecular mechanism of endosulfan-induced DNA damage response in human leukemia cells. We performed endosulfan exposure experiments in K562 cells with varying concentrations of endosulfan for 48 h and found that endosulfan lowered cell viability in a dose-dependent manner. We observed the dramatic DNA damage using comet assay and the increase of micronucleus in 75 μM endosulfan-exposed cells. Endosulfan at 75 μM caused the expression alterations of ATM and DNA repair genes such as FANCD2, and BRCA1/2 at different exposure time points (12, 24, 48 h), which was reversed by ATM inhibitor KU-55933. Endosulfan significantly increased the mRNA expression levels of p53 and GADD45A, and decreased PCNA and XRCC2 at 48 h after exposure. Flow cytometric analysis showed that endosulfan at 50 and 75 μM induced cell cycle G1 arrest, a response attributed to down-regulation of CDK6 and up-regulation of p21. We also observed that endosulfan at 50 and 75 μM induced a considerable percentage of cells to undergo apoptosis, as detected by Annexin-V binding assays. Endosulfan resulted in the activation of caspase-3, and elevated the expression levels of PUMA and the ratio of BAX/Bcl-2. These findings suggest that endosulfan caused DNA damage response throughATM-p53 signaling pathway, implicating the potential correlation between endosulfan and leukemia.
接触杀虫剂会导致 DNA 损伤和基因组不稳定。我们之前预测过，硫丹可能与白血病有关，但硫丹在白血病细胞中的作用尚未得到探索。本研究旨在阐明硫丹诱导人白血病细胞 DNA 损伤反应的分子机制。我们在 K562 细胞中进行了硫丹暴露实验，用不同浓度的硫丹处理细胞 48 小时，发现硫丹以剂量依赖的方式降低细胞活力。我们使用彗星试验观察到明显的 DNA 损伤，以及在 75 μM 硫丹暴露的细胞中微核的增加。75 μM 的硫丹在不同的暴露时间点（12、24、48 小时）引起 ATM 和 DNA 修复基因（如 FANCD2 和 BRCA1/2）的表达改变，这些改变可以被 ATM 抑制剂 KU-55933 逆转。硫丹在暴露后 48 小时显著增加了 p53 和 GADD45A 的 mRNA 表达水平，并降低了 PCNA 和 XRCC2 的表达水平。流式细胞术分析显示，50 和 75 μM 的硫丹诱导细胞周期 G1 期阻滞，这一反应归因于 CDK6 的下调和 p21 的上调。我们还观察到，50 和 75 μM 的硫丹诱导相当比例的细胞发生凋亡，这可以通过 Annexin-V 结合试验检测到。硫丹导致 caspase-3 的激活，并增加了 PUMA 的表达水平和 BAX/Bcl-2 的比值。这些发现表明，硫丹通过 ATM-p53 信号通路引起 DNA 损伤反应，暗示了硫丹与白血病之间的潜在相关性。
