BRCA2 and RAD51 promote double-strand break formation and cell death in response to gemcitabine.
BRCA2 and RAD51 promote double-strand break formation and cell death in response to gemcitabine.
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DOI：
10.1158/1535-7163.mct-13-0862
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发表时间：
2014-10
影响因子：
5.7
通讯作者：
Petermann E
中科院分区：
文献类型：
--
作者：
Jones RM;Kotsantis P;Stewart GS;Groth P;Petermann E
复制抑制剂导致复制叉停滞和双链断裂（DSB），这是由停滞叉的处理引起的。在从复制块恢复期间，同源重组（HR）因子RAD51介导叉重新启动和DSB修复。因此，HR缺陷使细胞对复制抑制剂敏感，这对癌症治疗有明确的意义。吉西他滨是一种有效的复制抑制剂，用于治疗HR基因（如BRCA2）突变的癌症。在这里，我们调查为什么，矛盾的是，HR基因突变保护细胞免受吉西他滨的杀伤。使用哺乳动物细胞中的DNA复制和损伤测定，我们表明，即使是短吉西他滨治疗引起持续的复制抑制。BRCA2和RAD51在药物去除后早期被招募到染色质中，积极抑制复制叉进展并促进MUS81和XPF依赖性DSB的形成，这些DSB保持未修复。我们的数据表明，在吉西他滨失速叉形成的HR中间体转化为DSB，从而导致吉西他滨诱导的细胞死亡，这可能对HR缺陷型肿瘤的治疗反应有影响。
Replication inhibitors cause replication fork stalling and double-strand breaks (DSBs) that result from processing of stalled forks. During recovery from replication blocks, the homologous recombination (HR) factor RAD51 mediates fork restart and DSB repair. HR defects therefore sensitise cells to replication inhibitors, with clear implications for cancer therapy. Gemcitabine is a potent replication inhibitor used to treat cancers with mutations in HR genes such as BRCA2. Here we investigate why, paradoxically, mutations in HR genes protect cells from killing by Gemcitabine. Using DNA replication and -damage assays in mammalian cells, we show that even short Gemcitabine treatments cause persistent replication inhibition. BRCA2 and RAD51 are recruited to chromatin early after removal of the drug, actively inhibit replication fork progression and promote the formation of MUS81- and XPF-dependent DSBs that remain unrepaired. Our data suggest that HR intermediates formed at Gemcitabine-stalled forks are converted into DSBs and thus contribute to Gemcitabine-induced cell death, which could have implications for the treatment response of HR-deficient tumours.