Potentiation of the novel topoisomerase I inhibitor indenoisoquinoline LMP-400 by the cell checkpoint and Chk1-Chk2 inhibitor AZD7762.
Potentiation of the novel topoisomerase I inhibitor indenoisoquinoline LMP-400 by the cell checkpoint and Chk1-Chk2 inhibitor AZD7762.
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DOI：
10.1158/0008-5472.can-11-2579
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发表时间：
2012-02-15
期刊：
影响因子：
11.2
通讯作者：
Pommier Y
中科院分区：
文献类型：
--
作者：
Aris SM;Pommier Y
新型拓扑异构酶I（Top1）抑制剂正在临床开发中以规避喜树碱的缺点。在这里，我们报告了对LMP-400的分子研究，LMP-400是一种1期临床试验中的茚并异喹啉Top1抑制剂，单独使用以及与细胞周期检查点抑制剂AZD 7762联合使用。我们研究了药物对DNA复制和癌细胞杀伤的影响，发现LMP-400与AZD 7762联合使用时在人结肠癌细胞中显示出协同抗增殖活性。LMP-400和喜树碱（CPT）对S期进展和溴脱氧尿苷掺入的抑制作用相似，但AZD 7762可消除。通过单DNA分子分析和免疫荧光显微镜（分子梳理）研究的复制显示，对LMP-400处理的响应迅速抑制了分叉进展，随后在添加AZD 7762后重现。在LMP-400处理的细胞中，纳摩尔浓度的AZD 7762可抑制Chk 1和Chk 2的活化/自磷酸化。AZD 7762对Chk 1和Chk 2的这种强效双重抑制作用低于消除细胞周期抑制并与LMP-400产生协同作用所需的药物浓度。此外，在Chk 2补充细胞和Chk 2敲除细胞中，协同作用不依赖于Chk 2，表明AZD 7762废除细胞周期的其他机制。总之，我们的研究结果证明了将细胞周期检查点抑制剂与新型非喜树碱茚并异喹啉Top1抑制剂相结合的基本原理。
Novel topoisomerase I (Top1) inhibitors are in clinical development to circumvent the drawbacks of camptothecins. Here we report molecular investigations into LMP-400, an indenoisoquinoline Top1 inhibitor in Phase 1 clinical trial, by itself and in combination with the cell cycle checkpoint inhibitor, AZD7762. We examined drug effects on DNA replication and killing of cancer cells and found that LMP-400 showed synergistic antiproliferative activity when combined with AZD7762 in human colon carcinoma cells. Inhibition of S-phase progression and bromodeoxyuridine incorporation were similarly induced by LMP-400 and camptothecin (CPT) and were abrogated by AZD7762. Replication studied by single DNA molecule analyses and immunofluorescence microscopy (molecular combing) showed rapid inhibition of fork progression in response to LMP-400 treatment with subsequent recapitulation after AZD7762 addition. AZD7762 inhibited both the activation/autophosphosphorylation of Chk1 and Chk2 at nanomolar concentrations in LMP-400-treated cells. This potent dual inhibition of Chk1 and Chk2 by AZD7762 was below the drug concentrations required to abrogate cell cycle inhibition and produce synergism with LMP-400. Also, the synergism was independent of Chk2 both in Chk2-complemented cells and Chk2 knockout cells, suggesting additional mechanisms for cell cycle abrogation by AZD7762. Together, our findings demonstrate a rationale for combining cell cycle checkpoint inhibitors with the novel non-camptothecin indenoisoquinoline Top1 inhibitors.