Chien Ming-Hsien, Chow Jyh-Ming, Lee Wei-Jiunn, Chen Hui-Yu, Tan Peng, Wen Yu-Ching, Lin Yung-Wei, Hsiao Pei-Ching, Yang Shun-Fa
Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan.
Department of Medical Education and Research, Wan Fang Hospital, Taipei Medical University, Taipei 116, Taiwan.
Int J Mol Sci. 2017 Jul 31;18(8):1667. doi: 10.3390/ijms18081667.
Tricetin is a dietary flavonoid with cytostatic properties and antimetastatic activities in various solid tumors. The anticancer effect of tricetin in nonsolid tumors remains unclear. Herein, the molecular mechanisms by which tricetin exerts its anticancer effects on acute myeloid leukemia (AML) cells were investigated. Results showed that tricetin inhibited cell viability in various types of AML cell lines. Tricetin induced morphological features of apoptosis such as chromatin condensation and phosphatidylserine (PS) externalization, and significantly activated proapoptotic signaling including caspase-8, -9, and -3 activation and poly(ADP-ribose) polymerase (PARP) cleavage in HL-60 AML cells. Of note, tricetin-induced cell growth inhibition was dramatically reversed by a pan caspase and caspase-8- and -9-specific inhibitors, suggesting that this compound mainly acts through a caspase-dependent pathway. Moreover, treatment of HL-60 cells with tricetin induced sustained activation of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), and inhibition of ERK and JNK by their specific inhibitors respectively promoted and abolished tricetin-induced cell apoptosis. Dichlorofluorescein (DCF) staining showed that intracellular reactive oxygen species (ROS) levels were higher in tricetin-treated HL-60 cells compared to the control group. Moreover, an ROS scavenger, N-acetylcysteine (NAC), reversed tricetin-induced JNK activation and subsequent cell apoptosis. In conclusion, our results indicated that tricetin induced cell death of leukemic HL-60 cells through induction of intracellular oxidative stress following activation of a JNK-mediated apoptosis pathway. A combination of tricetin and an ERK inhibitor may be a better strategy to enhance the anticancer activities of tricetin in AML.
三甲沙汀是一种具有细胞生长抑制特性和对多种实体瘤有抗转移活性的膳食类黄酮。三甲沙汀在非实体瘤中的抗癌作用仍不清楚。在此，研究了三甲沙汀对急性髓系白血病（AML）细胞发挥抗癌作用的分子机制。结果表明，三甲沙汀抑制了多种类型AML细胞系的细胞活力。三甲沙汀诱导了凋亡的形态学特征，如染色质浓缩和磷脂酰丝氨酸（PS）外化，并在HL-60 AML细胞中显著激活了促凋亡信号，包括半胱天冬酶-8、-9和-3的激活以及聚（ADP-核糖）聚合酶（PARP）的裂解。值得注意的是，泛半胱天冬酶以及半胱天冬酶-8和-9特异性抑制剂显著逆转了三甲沙汀诱导的细胞生长抑制，表明该化合物主要通过半胱天冬酶依赖性途径发挥作用。此外，用三甲沙汀处理HL-60细胞可诱导细胞外信号调节激酶（ERK）和c-Jun氨基末端激酶（JNK）的持续激活，分别用其特异性抑制剂抑制ERK和JNK可促进和消除三甲沙汀诱导的细胞凋亡。二氯荧光素（DCF）染色显示，与对照组相比，三甲沙汀处理的HL-60细胞中细胞内活性氧（ROS）水平更高。此外，一种ROS清除剂N-乙酰半胱氨酸（NAC）逆转了三甲沙汀诱导的JNK激活及随后的细胞凋亡。总之，我们的结果表明，三甲沙汀通过激活JNK介导的凋亡途径后诱导细胞内氧化应激，从而诱导白血病HL-60细胞死亡。三甲沙汀与ERK抑制剂联合使用可能是增强三甲沙汀在AML中抗癌活性的更好策略。
