The iron chelator Dp44mT causes DNA damage and selective inhibition of topoisomerase IIalpha in breast cancer cells.
The iron chelator Dp44mT causes DNA damage and selective inhibition of topoisomerase IIalpha in breast cancer cells.
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DOI：
10.1158/0008-5472.can-08-1437
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发表时间：
2009-02-01
期刊：
影响因子：
11.2
通讯作者：
Shacter EB
中科院分区：
文献类型：
--
作者：
Rao VA;Klein SR;Agama KK;Toyoda E;Adachi N;Pommier Y;Shacter EB
二-2-吡啶基酮-4,4，-二甲基-3-硫代氨基脲（Dp44mT）是一种具有选择性抗癌活性的铁螯合剂。我们研究了Dp44mT杀死乳腺癌细胞的机制，无论是单独使用还是与阿霉素联合使用。与健康乳腺上皮细胞（MCF-12A）相比，Dp44mT单独诱导乳腺癌细胞系MDA-MB-231的选择性细胞杀伤。它诱导G1细胞周期阻滞，并在纳摩尔浓度下降低癌细胞的克隆生长。Dp44mT，而不是铁螯合剂desferal，在MDA-MB-231细胞中诱导DNA双链断裂，定量为S139磷酸化组蛋白灶（γ-H2AX）和彗星尾。低浓度Dp44mT存在时，多柔比星诱导的细胞毒性和DNA损伤均显著增强。通过体外DNA切割实验和细胞拓扑异构酶-DNA复合物形成测定，螯合剂引起DNA拓扑异构酶IIα (top2α)选择性中毒。与等基因的top2α+/+或top2β - / -细胞相比，杂合的Nalm-6 top2α敲除细胞（top2α+/ -）对dp44mt诱导的细胞毒性具有部分抗性。通过在HeLa细胞中敲除top2α和top2β小干扰BNA，证实了top2α的特异性。结果表明，Dp44mT对乳腺癌细胞具有细胞毒性，至少部分原因是选择性抑制top2α。因此，由于其螯合铁和抑制top2α活性的双重能力，Dp44mT可能作为一种机制独特的癌症治疗方法。
Di-2-pyridylketone-4,4,-dimethyl-3-thiosemicarbazone (Dp44mT) is being developed as an iron chelator with selective anticancer activity. We investigated the mechanism whereby Dp44mT kills breast cancer cells, both as a single agent and in combination with doxorubicin. Dp44mT alone induced selective cell killing in the breast cancer cell line MDA-MB-231 when compared with healthy mammary epithelial cells (MCF-12A). It induces G1 cell cycle arrest and reduces cancer cell clonogenic growth at nanomolar concentrations. Dp44mT, but not the iron chelator desferal, induces DNA double-strand breaks quantified as S139 phosphorylated histone foci (γ-H2AX) and Comet tails induced in MDA-MB-231 cells. Doxorubicin-induced cytotoxicity and DNA damage were both enhanced significantly in the presence of low concentrations of Dp44mT. The chelator caused selective poisoning of DNA topoisomerase IIα (top2α) as measured by an in vitro DNA cleavage assay and cellular topoisomerase-DNA complex formation. Heterozygous Nalm-6 top2α knockout cells (top2α+/− ) were partially resistant to Dp44mT-induced cytotoxicity compared with isogenic top2α+/+ or top2β−/− cells. Specificity for top2α was confirmed using top2α and top2β small interfering BNA knockdown in HeLa cells. The results show that Dp44mT is cytotoxic to breast cancer cells, at least in part, due to selective inhibition of top2α. Thus, Dp44mT may serve as a mechanistically unique treatment for cancer due to its dual ability to chelate iron and inhibit top2α activity.