Park Iha, Avraham Hava Karsenty
Division of Experimental Medicine, Beth Israel Deaconess Medical Center, Harvard Institutes of Medicine, 4 Blackfan Circle, 3rd Floor, Boston, MA 02115, USA.
Exp Cell Res. 2006 Jul 1;312(11):1996-2008. doi: 10.1016/j.yexcr.2006.02.029. Epub 2006 Apr 21.
Topoisomerase II is essential for cell proliferation and survival and has been a target of various anticancer drugs. ICRF-193 has long been used as a catalytic inhibitor to study the function of topoisomerase II. Here, we show that ICRF-193 treatment induces DNA damage signaling. Treatment with ICRF-193 induced G2 arrest and DNA damage signaling involving gamma-H2AX foci formation and CHK2 phosphorylation. DNA damage by ICRF-193 was further demonstrated by formation of the nuclear foci of 53BP1, NBS1, BRCA1, MDC1, and FANCD2 and increased comet tail moment. The DNA damage signaling induced by ICRF-193 was mediated by ATM and ATR and was restricted to cells in specific cell cycle stages such as S, G2, and mitosis including late and early G1 phases. Downstream signaling of ATM and ATR involved the phosphorylation of CHK2 and BRCA1. Altogether, our results demonstrate that ICRF-193 induces DNA damage signaling in a cell cycle-dependent manner and suggest that topoisomerase II might be essential for the progression of the cell cycle at several stages including DNA decondensation.
拓扑异构酶II对细胞增殖和存活至关重要，一直是各种抗癌药物的作用靶点。长期以来，ICRF-193一直被用作催化抑制剂来研究拓扑异构酶II的功能。在此，我们表明ICRF-193处理可诱导DNA损伤信号。用ICRF-193处理可诱导G2期阻滞以及涉及γ-H2AX灶形成和CHK2磷酸化的DNA损伤信号。53BP1、NBS1、BRCA1、MDC1和FANCD2核灶的形成以及彗星尾矩增加进一步证明了ICRF-193造成的DNA损伤。ICRF-193诱导的DNA损伤信号由ATM和ATR介导，并且仅限于特定细胞周期阶段的细胞，如S期、G2期以及包括G1期晚期和早期的有丝分裂期。ATM和ATR的下游信号涉及CHK2和BRCA1的磷酸化。总之，我们的结果表明ICRF-193以细胞周期依赖性方式诱导DNA损伤信号，并提示拓扑异构酶II可能在包括DNA解聚在内的几个阶段对细胞周期进程至关重要。
