Anthocyanidins modulate the activity of human DNA topoisomerases I and II and affect cellular DNA integrity
Anthocyanidins modulate the activity of human DNA topoisomerases I and II and affect cellular DNA integrity
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DOI：
10.1021/tx050039n
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发表时间：
2005-09-01
影响因子：
4.1
通讯作者：
Marko, D
中科院分区：
文献类型：
--
作者：
Habermeyer, M;Fritz, J;Marko, D
在本研究中，我们研究了花青素对人类拓扑异构酶 I 和 II 的影响及其与人类细胞内 DNA 完整性的相关性。 B 环上带有邻位羟基的花青素（花翠素，DEL；花青素，CY）被发现可有效抑制人拓扑异构酶 I 和 II 的催化活性，且不区分 II α 和 II β 亚型。然而，与拓扑异构酶毒物相反，DEL 和 CY 不能稳定拓扑异构酶 I 或 II 的共价 DNA-拓扑异构酶中间体（可裂解复合物）。使用重组拓扑异构酶 I，CY 或 DEL (>= 1 mu M) 的存在有效地抑制了拓扑异构酶 I 毒物喜树碱对可裂解复合物的稳定作用。我们还进一步研究了对拓扑异构酶 I 毒物的潜在保护作用是否也反映在细胞水平上，从而影响喜树碱的 DNA 损伤特性。事实上，在HT29细胞中，低微摩尔浓度的DEL（1-10μM）显着减弱了喜树碱（100μM）的DNA链断裂作用。然而，在浓度 >= 50 μM 时，所有测试的花青素（飞燕草素、矢车菊素、锦葵素、天竺葵素和芍药素），包括那些不干扰拓扑异构酶的花青素，都被发现在彗星测定中诱导 DNA 链断裂。所有这些类似物都能够与溴化乙锭竞争嵌入小牛胸腺 DNA 并取代小沟结合剂 Hoechst 33258。这些数据表明对双链 DNA 具有显着的亲和力，这可能至少有助于较高浓度（> = 50 mu M）花青素的 DNA 链断裂作用。
In the present study, we investigated the effect of anthocyanidins on human topoisomerases I and II and its relevance for DNA integrity within human cells. Anthocyanidins bearing vicinal hydroxy groups at the B-ring (delphinidin, DEL; cyanidin, CY) were found to potently inhibit the catalytic activity of human topoisomerases I and II, without discriminating between the II alpha and the II beta isoforms. However, in contrast to topoisomerase poisons, DEL and CY did not stabilize the covalent DNA-topoisomerase intermediates (cleavable complex) of topoisomerase I or II. Using recombinant topoisomerase I, the presence of CY or DEL (>= 1 mu M) effectively prohibited the stabilization of the cleavable complex by the topoisomerase I poison camptothecin. We furthermore investigated whether the potential protective effect vs topoisomerase I poisons is reflected also on the cellular level, affecting the DNA damaging properties of camptothecin. Indeed, in HT29 cells, low micromolar concentrations of DEL (1-10 mu M) significantly diminished the DNA strand breaking effect of camptothecin (100 mu M). However, at concentrations >= 50 mu M, all anthocyanidins tested (delphinidin, cyanidin, malvidin, pelargonidin, and paeonidin), including those not interfering with topoisomerases, were found to induce DNA strand breaks in the comet assay. All of these analogues were able to compete with ethidium bromide for the intercalation into calf thymus DNA and to replace the minor groove binder Hoechst 33258. These data indicate substantial affinity to double-stranded DNA, which might contribute at least to the DNA strand breaking effect of anthocyanidins at higher concentrations (>= 50 mu M).