Chk2 kinase is required for methylglyoxal-induced G2/M cell-cycle checkpoint arrest:: implication of cell-cycle checkpoint regulation in diabetic oxidative stress signaling
Chk2 kinase is required for methylglyoxal-induced G2/M cell-cycle checkpoint arrest:: implication of cell-cycle checkpoint regulation in diabetic oxidative stress signaling
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DOI：
10.1111/j.1365-2443.2007.01100.x
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发表时间：
2007-08-01
期刊：
影响因子：
2.1
通讯作者：
Minami, Yasuhiro
中科院分区：
文献类型：
--
作者：
Kani, Shuichi;Nakayama, Emiko;Minami, Yasuhiro
甲基乙二醛 (MG) 是一种反应性内源代谢物，由磷酸丙糖降解过程产生。在高血糖条件下，由于前体浓度升高，MG 形成速率增加。已经确定 MG 引发氧化应激信号传导，导致 MAP 激酶、p38 MAPK 和 JNK 的激活，但细胞周期检查点调节在 MG 诱导的信号传导中的作用仍然知之甚少。在这里，我们发现检查点激酶 Chk1 和 Chk2 及其上游 ATM 激酶在 MG 处理培养细胞后被磷酸化并激活。 MG 诱导的 Chk1 和 Chk2 激活被氨基胍 (AG)（一种晚期糖基化终末产物 (AGE) 产生的抑制剂）或 N-乙酰基-L-半胱氨酸 (NAC)（一种抗氧化剂）以剂量依赖性方式抑制，表明 AGE 引起的氧化应激在 MG 激活 Chk1 和 Chk2 中发挥着关键作用。此外，发现细胞周期同步细胞在 MG 处理后表现出 G(2)/M 检查点停滞，并且 siRNA 介导的 Chk2（而非 Chk1）敲低会导致 MG 诱导的 G(2)/M 停滞失败。因此，结果表明 Chk2 在 MG 诱导的 G(2)/M 细胞周期检查点停滞中发挥关键作用。
Methylglyoxal (MG) is a reactive endogenous metabolite that is produced from the process of degradation of triose-phosphates. Under hyperglycemic conditions the rate of MG formation increases as a result of elevated concentrations of precursors. It has been established that MG elicits oxidative stress signaling, leading to the activation of MAP kinases, p38 MAPK and JNK, yet it remains largely unknown about a role of cell-cycle checkpoint regulation in MG-induced signaling. Here, we show that checkpoint kinases, Chk1 and Chk2, as well as their upstream ATM kinase are phosphorylated and activated following MG treatment of cultured cells. This MG-induced activation of Chk1 and Chk2 were inhibited by either aminoguanidine (AG), an inhibitor of production of advanced glycation end products (AGEs) or N-acetyl-L-cysteine (NAC), an antioxidant in dose dependent manners, indicating that oxidative stress via AGEs is involved critically in the activation of Chk1 and Chk2 by MG. Furthermore, it was found that cell-cycle synchronized cells exhibited G(2)/M checkpoint arrest following MG treatment, and that siRNA-mediated knock-down of Chk2, but not Chk1, results in a failure of MG-induced G(2)/M arrest. Thus, the results indicate a critical role for Chk2 in MG-induced G(2)/M cell-cycle checkpoint arrest.