Roh Jong-Lyel, Kim Eun Hye, Jang Hyejin, Shin Daiha
Department of Otolaryngology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
Department of Otolaryngology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
Redox Biol. 2017 Apr;11:254-262. doi: 10.1016/j.redox.2016.12.010. Epub 2016 Dec 18.
Artesunate, an anti-malarial drug, has been repurposed as an anticancer drug due to its induction of cell death via reactive oxygen species (ROS) production. However, the molecular mechanisms regulating cancer cell death and the resistance of cells to artesunate remain unclear. We investigated the molecular mechanisms behind the antitumor effects of artesunate and an approach to overcome artesunate resistance in head and neck cancer (HNC). The effects of artesunate and trigonelline were tested in different HNC cell lines, including three cisplatin-resistant HNC cell lines. The effects of these drugs as well as the inhibition of Keap1, Nrf2, and HO-1 were assessed by cell viability, cell death, glutathione (GSH) and ROS production, protein expression, and mouse tumor xenograft models. Artesunate selectively killed HNC cells but not normal cells. The artesunate sensitivity was relatively low in cisplatin-resistant HNC cells. Artesunate induced ferroptosis in HNC cells by decreasing cellular GSH levels and increasing lipid ROS levels. This effect was blocked by co-incubation with ferrostatin-1 and a trolox pretreatment. Artesunate activated the Nrf2-antioxidant response element (ARE) pathway in HNC cells, which contributed to ferroptosis resistance. The silencing of Keap1, a negative regulator of Nrf2, decreased artesunate sensitivity in HNC cells. Nrf2 genetic silencing or trigonelline reversed the ferroptosis resistance of Keap1-silenced and cisplatin-resistant HNC cells to artesunate in vitro and in vivo. Nrf2-ARE pathway activation contributes to the artesunate resistance of HNC cells, and inhibition of this pathway abolishes ferroptosis-resistant HNC.
Our results show the effectiveness and molecular mechanism of artesunate treatment on head and neck cancer (HNC). Artesunate selectively killed HNC cells but not normal cells by inducing an iron-dependent, ROS-accumulated ferroptosis. However, this effect may be suboptimal in some cisplatin-resistant HNCs because of Nrf2-antioxidant response element (ARE) pathway activation. Inhibition of the Nrf2-ARE pathway increased artesunate sensitivity and reversed the ferroptosis resistance in resistant HNC cells.
青蒿琥酯是一种抗疟疾药物，因其通过产生活性氧（ROS）诱导细胞死亡而被重新用作抗癌药物。然而，调节癌细胞死亡的分子机制以及细胞对青蒿琥酯的耐药性仍不清楚。我们研究了青蒿琥酯抗肿瘤作用背后的分子机制以及克服头颈癌（HNC）对青蒿琥酯耐药性的方法。在不同的HNC细胞系中测试了青蒿琥酯和胡芦巴碱的作用，包括三种顺铂耐药的HNC细胞系。通过细胞活力、细胞死亡、谷胱甘肽（GSH）和ROS产生、蛋白质表达以及小鼠肿瘤异种移植模型评估了这些药物的作用以及对Keap1、Nrf2和HO-1的抑制作用。青蒿琥酯选择性杀死HNC细胞而非正常细胞。顺铂耐药的HNC细胞对青蒿琥酯的敏感性相对较低。青蒿琥酯通过降低细胞内GSH水平和增加脂质ROS水平诱导HNC细胞发生铁死亡。与铁死亡抑制剂-1共同孵育和用生育三烯酚预处理可阻断这种作用。青蒿琥酯激活了HNC细胞中的Nrf2-抗氧化反应元件（ARE）途径，这导致了铁死亡抗性。Keap1（Nrf2的负调节因子）的沉默降低了HNC细胞对青蒿琥酯的敏感性。Nrf2基因沉默或胡芦巴碱在体外和体内逆转了Keap1沉默和顺铂耐药的HNC细胞对青蒿琥酯的铁死亡抗性。
我们的结果显示了青蒿琥酯治疗头颈癌（HNC）的有效性和分子机制。青蒿琥酯通过诱导铁依赖性、ROS积累的铁死亡选择性杀死HNC细胞而非正常细胞。然而，由于Nrf2-抗氧化反应元件（ARE）途径的激活，这种作用在一些顺铂耐药的HNC中可能不是最佳的。抑制Nrf2-ARE途径可增加青蒿琥酯敏感性并逆转耐药HNC细胞中的铁死亡抗性。
