Vorinostat Induces Reactive Oxygen Species and DNA Damage in Acute Myeloid Leukemia Cells

Histone deacetylase inhibitors (HDACi) are promising anti-cancer agents, however, their mechanisms of action remain unclear. In acute myeloid leukemia (AML) cells, HDACi have been reported to arrest growth and induce apoptosis. In this study, we elucidate details of the DNA damage induced by the HDACi vorinostat in AML cells. At clinically relevant concentrations, vorinostat induces double-strand breaks and oxidative DNA damage in AML cell lines. Additionally, AML patient blasts treated with vorinostat display increased DNA damage, followed by an increase in caspase-3/7 activity and a reduction in cell viability. Vorinostat-induced DNA damage is followed by a G2-M arrest and eventually apoptosis. We found that pre-treatment with the antioxidant N-acetyl cysteine (NAC) reduces vorinostat-induced DNA double strand breaks, G2-M arrest and apoptosis. These data implicate DNA damage as an important mechanism in vorinostat-induced growth arrest and apoptosis in both AML cell lines and patient-derived blasts. This supports the continued study and development of vorinostat in AMLs that may be sensitive to DNA-damaging agents and as a combination therapy with ionizing radiation and/or other DNA damaging agents.

组蛋白去乙酰化酶抑制剂（Histone deacetylase inhibitors, HDACi）是一类颇具前景的抗癌药物，但其具体作用机制仍有待阐明。已有研究显示，在急性髓系白血病（acute myeloid leukemia, AML）细胞中，HDACi可阻滞细胞增殖并诱导细胞凋亡。本研究详细解析了HDACi伏立诺他（vorinostat）诱导AML细胞DNA损伤的具体机制。在临床相关浓度条件下，伏立诺他可在AML细胞系中诱导DNA双链断裂与氧化性DNA损伤。进一步实验发现，经伏立诺他处理的AML患者原始细胞会出现DNA损伤水平升高，随后伴随半胱天冬氨酸蛋白酶3/7活性上调以及细胞存活率下降。伏立诺他诱导的DNA损伤会触发G2/M期阻滞，最终引发细胞凋亡。我们的研究表明，采用抗氧化剂N-乙酰半胱氨酸（N-acetyl cysteine, NAC）进行预处理，可有效减轻伏立诺他诱导的DNA双链断裂、G2/M期阻滞与细胞凋亡。上述数据证实，DNA损伤是伏立诺他在AML细胞系及患者来源的原始细胞中诱导增殖阻滞与细胞凋亡的关键机制。该研究结果支持继续开展伏立诺他在对DNA损伤剂敏感的AML中的研发工作，以及将其与电离辐射或其他DNA损伤剂联合应用的联合疗法探索。