Acetylshikonin (ASK) is a natural naphthoquinone derivative of traditional Chinese medicine Lithospermum erythrorhyzon. It has been reported that ASK has bactericidal, anti-inflammatory and antitumour effects. However, whether ASK induces apoptosis and autophagy in acute myeloid leukaemia (AML) cells and the underlying mechanism are still unclear. Here, we explored the roles of apoptosis and autophagy in ASK-induced cell death and the potential molecular mechanisms in human AML HL-60 cells. The results demonstrated that ASK remarkably inhibited the cell proliferation, viability and induced apoptosis in HL-60 cells through the mitochondrial pathway, and ASK promoted cell cycle arrest in the S-phase. In addition, the increased formation of autophagosomes, the turnover from light chain 3B (LC3B) I to LC3B II and decrease of P62 suggested the induction of autophagy by ASK. Furthermore, ASK significantly decreased PI3K, phospho-Akt and p-p70S6K expression, while enhanced phospho-AMP-activated protein kinase (AMPK) and phospho-liver kinase B1(LKB1) expression. The suppression of ASK-induced the conversion from LC3B I to LC3B II caused by the application of inhibitors of AMPK (compound C) demonstrated that ASK-induced autophagy depends on the LKB1/AMPK pathway. These data suggested that the autophagy induced by ASK were dependent on the activation of LKB1/AMPK signalling and suppression of PI3K/Akt/mTOR pathways. The cleavage of the apoptosis-related markers caspase-3 and caspase-9 and the activity of caspase-3 induced by ASK were markedly reduced by inhibitor of AMPK (compound C), an autophagy inhibitor 3-methyladenine (3-MA) and another autophagy inhibitor chloroquine (CQ). Taken together, our data reveal that ASK-induced HL-60 cell apoptosis is dependent on the activation of autophagy via the LKB1/AMPK and PI3K/Akt-regulated mTOR signalling pathways.

中文翻译：

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乙酰紫草素通过关键的 LKB1-AMPK 和 PI3K/Akt 调节的 mTOR 信号通路在 HL-60 细胞中诱导自噬依赖性细胞凋亡

乙酰紫草素（ASK）是中药紫草的天然萘醌衍生物. 据报道，ASK具有杀菌、抗炎和抗肿瘤作用。然而，ASK 是否诱导急性髓系白血病（AML）细胞凋亡和自噬及其潜在机制仍不清楚。在这里，我们探讨了凋亡和自噬在 ASK 诱导的细胞死亡中的作用以及人 AML HL-60 细胞中的潜在分子机制。结果表明，ASK通过线粒体途径显着抑制HL-60细胞的增殖、活力和诱导凋亡，ASK促进细胞周期停滞在S期。此外，自噬体形成的增加、从轻链 3B (LC3B) I 到 LC3B II 的转换以及 P62 的减少表明 ASK 诱导了自噬。此外，ASK 显着降低了 PI3K、磷酸化 Akt 和 p-p70S6K 的表达，同时增强磷酸-AMP 活化蛋白激酶 (AMPK) 和磷酸-肝激酶 B1(LKB1) 的表达。抑制 ASK 诱导的 LC3B I 到 LC3B II 的转化是由应用 AMPK 抑制剂（化合物 C）引起的，这表明 ASK 诱导的自噬依赖于 LKB1/AMPK 途径。这些数据表明，ASK 诱导的自噬依赖于 LKB1/AMPK 信号通路的激活和 PI3K/Akt/mTOR 通路的抑制。AMPK 抑制剂（化合物 C）、自噬抑制剂 3-甲基腺嘌呤 (3-MA) 和另一种自噬抑制剂显着降低了凋亡相关标志物 caspase-3 和 caspase-9 的切割以及 ASK 诱导的 caspase-3 的活性。自噬抑制剂氯喹（CQ）。综合起来，