CELL-DEATH INDUCED BY TOPOISOMERASE INHIBITORS - ROLE OF CALCIUM IN MAMMALIAN-CELLS
CELL-DEATH INDUCED BY TOPOISOMERASE INHIBITORS - ROLE OF CALCIUM IN MAMMALIAN-CELLS
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DOI：
10.1016/0006-2952(91)90683-v
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发表时间：
1991-06-21
影响因子：
5.8
通讯作者：
POMMIER, Y
中科院分区：
文献类型：
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作者：
BERTRAND, R;KERRIGAN, D;POMMIER, Y
虽然依托泊苷（VP-16）对拓扑异构酶II可切割复合物的稳定性已被认为对细胞杀伤很重要，但可切割复合物形成后的致死事件仍有待阐明。为了描述vp -16诱导的细胞毒性的生化需求，我们研究了钙缺乏对中国仓鼠DC3F细胞的影响。在无钙培养基中或在含有5 mM[乙二（氧乙二腈）]四乙酸（EGTA）的完全培养基中预孵育4小时，可防止VP-16的细胞毒性。在相同的条件下，在缺钙细胞中，vp -16诱导的DNA单链断裂频率与对照细胞相似。细胞周期分析和胸苷脉冲掺入表明，钙缺乏没有改变DNA合成和细胞周期分布。缺钙细胞用含钙培养基复育后4-8小时内，药物诱导的细胞毒性逐渐恢复。在DC3F细胞中，钙缺乏也可以保护细胞免受喜树碱、高温的细胞毒性，在较小程度上，还可以防止氮芥和伽马辐射。在人结肠癌HT-29细胞中也得到了类似的结果。我们的研究结果表明，拓扑异构酶ii介导的DNA断裂仅具有潜在的致命性，并且拓扑异构酶抑制剂的细胞毒性需要钙依赖的细胞过程。
Although the stabilization of topoisomerase II cleavable complexes by etoposide (VP-16) has been recognized to be important for cell killing, the lethal events following the formation of cleavable complexes remain to be elucidated. In an attempt to characterize the biochemical requirements for VP-16-induced cytotoxicity, we examined the effects of calcium depletion in Chinese hamster DC3F cells. Four-hour preincubation in calcium-free medium or in complete medium containing 5 mM [ethylenebis(oxyethylenenitrilo)]tetraacetic acid (EGTA) protected against the cytotoxicity of VP-16. Under these same conditions, the VP-16-induced DNA single-strand break frequency in calcium-depleted cells remained similar to that of control cells. Cell-cycle analysis and thymidine pulse incorporation indicated that calcium depletion did not alter DNA synthesis and cell cycle distribution. Drug-induced cytotoxicity was restored progressively within 4-8 hr after calcium-depleted cells were refed with calcium-containing medium. Calcium depletion also protected against the cytotoxicity of camptothecin, hyperthermia and, to a lesser extent, nitrogen mustard and gamma radiation in DC3F cells. Similar results were obtained in human colon carcinoma HT-29 cells. Our results suggest that topoisomerase II-mediated DNA breaks are only potentially lethal and that calcium-dependent cellular processes are required for the cytotoxicity of topoisomerase inhibitors.