CBP-93872 inhibits NBS1-mediated ATR activation, abrogating maintenance of the DNA double-strand break-specific G2 checkpoint.
CBP-93872 inhibits NBS1-mediated ATR activation, abrogating maintenance of the DNA double-strand break-specific G2 checkpoint.
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DOI：
10.1158/0008-5472.can-13-3604
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发表时间：
2014-07
期刊：
影响因子：
11.2
通讯作者：
Takahisa Hirokawa;B. Shiotani;M. Shimada;K. Murata;Yoshikazu Johmura;M. Haruta;H. Tahara;H. Takeyama;M. Nakanishi
中科院分区：
文献类型：
--
作者：
Takahisa Hirokawa;B. Shiotani;M. Shimada;K. Murata;Yoshikazu Johmura;M. Haruta;H. Tahara;H. Takeyama;M. Nakanishi
CBP-93872先前使用基于细胞的高通量筛选系统鉴定为G2检查点抑制剂。然而，其分子作用以及细胞靶点在很大程度上是未知的。在这里，我们揭示了CBP-93872废除G2检查点的分子机制。CBP-93872通过抑制G2阻滞的维持而非起始，特异性消除DNA双链断裂（DSB）诱导的G2检查点，因为CBP-93872特异性抑制DSB依赖性ATR激活。因此，在CBP-93872存在下，DSB后Nbs 1和复制蛋白A2的ATR依赖性磷酸化被强烈抑制。CBP-93872似乎不抑制DNA末端切除，但在体外以剂量依赖性方式抑制Nbs 1依赖性和ssDNA诱导的ATR激活。综上所述，我们的研究结果表明CBP-93872是一种维持DSB特异性G2检查点的抑制剂，因此可能是一种强有力的候选药物，可以作为一种药物的基础，特异性地使p53突变的癌细胞对DSB诱导的DNA损伤治疗敏感。
CBP-93872 was previously identified as a G2 checkpoint inhibitor using a cell-based high-throughput screening system. However, its molecular actions as well as cellular targets are largely unknown. Here, we uncovered the molecular mechanisms underlying abrogation of the G2 checkpoint by CBP-93872. CBP-93872 specifically abrogates the DNA double-stranded break (DSB)-induced G2 checkpoint through inhibiting maintenance but not initiation of G2 arrest because of specific inhibition of DSB-dependent ATR activation. Hence, ATR-dependent phosphorylation of Nbs1 and replication protein A 2 upon DSB was strongly suppressed in the presence of CBP-93872. CBP-93872 did not seem to inhibit DNA-end resection, but did inhibit Nbs1-dependent and ssDNA-induced ATR activation in vitro in a dose-dependent manner. Taken together, our results suggest that CBP-93872 is an inhibitor of maintenance of the DSB-specific G2 checkpoint and thus might be a strong candidate as the basis for a drug that specifically sensitizes p53-mutated cancer cells to DSB-inducing DNA damage therapy.