Institute of Toxicology, University Medical Center, Johannes Gutenberg University, Mainz, Germany.
Mol Cancer Ther. 2011 Dec;10(12):2224-33. doi: 10.1158/1535-7163.MCT-11-0534. Epub 2011 Oct 13.
Artesunate, the active agent from Artemisia annua L. used in the traditional Chinese medicine, is being applied as a first-line drug for malaria treatment, and trials are ongoing that include this drug in cancer therapy. Despite increasing interest in its therapeutic application, the mode of cell killing provoked by artesunate in human cells is unknown. Here, we show that artesunate is a powerful inducer of oxidative DNA damage, giving rise to formamidopyrimidine DNA glycosylase-sensitive sites and the formation of 8-oxoguanine and 1,N6-ethenoadenine. Oxidative DNA damage was induced in LN-229 human glioblastoma cells dose dependently and was paralleled by cell death executed by apoptosis and necrosis, which could be attenuated by radical scavengers such as N-acetyl cysteine. Oxidative DNA damage resulted in DNA double-strand breaks (DSB) as determined by γH2AX foci that colocalized with 53BP1. Upon chronic treatment with artesunate, the level of DSB continuously increased over the treatment period up to a steady-state level, which is in contrast to ionizing radiation that induced a burst of DSB followed by a decline due to their repair. Knockdown of Rad51 by short interfering RNA and inactivation of DNA-PK strongly sensitized glioma cells to artesunate. These data indicate that both homologous recombination and nonhomologous end joining are involved in the repair of artesunate-induced DSB. Artesunate provoked a DNA damage response (DDR) with phosphorylation of ATM, ATR, Chk1, and Chk2. Overall, these data revealed that artesunate induces oxidative DNA lesions and DSB that continuously increase during the treatment period and accumulate until they trigger DDR and finally tumor cell death.
青蒿琥酯，一种源自黄花蒿的活性成分，被应用于传统中药中，目前被用作治疗疟疾的一线药物，并且正在进行临床试验，将其应用于癌症治疗。尽管人们对青蒿琥酯的治疗应用越来越感兴趣，但青蒿琥酯在人类细胞中引起细胞杀伤的模式尚不清楚。在这里，我们表明青蒿琥酯是一种强大的氧化 DNA 损伤诱导剂，导致形成嘧啶 DNA 糖基化酶敏感位点和 8-氧鸟嘌呤和 1，N6-烯腺嘌呤的形成。氧化 DNA 损伤在 LN-229 人胶质母细胞瘤细胞中呈剂量依赖性诱导，并且伴随着由凋亡和坏死执行的细胞死亡，这可以通过自由基清除剂如 N-乙酰半胱氨酸来减弱。氧化 DNA 损伤导致双链 DNA 断裂（DSB），如γH2AX 焦点所确定的，其与 53BP1 共定位。在慢性青蒿琥酯治疗中，DSB 的水平在治疗期间持续增加，直至达到稳定状态，这与电离辐射形成对比，电离辐射诱导 DSB 爆发，然后由于其修复而下降。通过短干扰 RNA 敲低 Rad51 和 DNA-PK 的失活强烈使神经胶质瘤细胞对青蒿琥酯敏感。这些数据表明同源重组和非同源末端连接都参与了青蒿琥酯诱导的 DSB 的修复。青蒿琥酯引起 DNA 损伤反应（DDR），导致 ATM、ATR、Chk1 和 Chk2 的磷酸化。总的来说，这些数据表明青蒿琥酯诱导氧化 DNA 损伤和 DSB，在治疗期间持续增加，并积累到它们触发 DDR 并最终导致肿瘤细胞死亡。
