Department of Pediatric Comprehensive Medicine, Gansu Provincial Maternity and Child-care Hospital, Lanzhou 730050, China.
Department of Hematology, Benxi Central Hospital, Benxi 117000, China.
Biomed Pharmacother. 2020 May;125:109819. doi: 10.1016/j.biopha.2020.109819. Epub 2020 Feb 25.
Acute myeloid leukemia (AML) is a complicated disease of hematopoietic stem cell disorders. However, its pathogenesis mechanisms and therapeutic treatments still remain vague. Asperuloside (ASP) is an iridoid glycoside found in Herba Paederiae, and is a component from traditional Chinese herbal medicine. ASP has been suggested to have various pharmacological activities, such as anti-tumor and anti-inflammation. In this study, we explored the effects of ASP on apoptosis and endoplasmic reticulum (ER) stress in human leukemia cells and in human primary leukemia blasts. ASP treatments selectively reduced the cell viability of human leukemia cells and primary leukemia blasts in a dose-dependent manner. We also found that ASP induced cell death via promoting the cleavage of Caspase-9, -3 and poly (ADP-ribose) polymerase (PARP), which was along with the loss of mitochondrial membrane potential and Cyto-c release from the mitochondria. In addition, we found that ASP significantly induced ER stress in leukemia cells by improving the protein expression levels of glucose-regulated protein of 78 kDa (GRP78), phosphorylated protein kinase RNA-like ER kinase (PERK), phosphorylated eukaryotic translation initiation factor 2 alpha (eIF2α), C/EBP homologous protein (CHOP), phosphorylated inositol-requiring enzyme 1 (p-IRE1), X-box binding protein 1 (XBP1), activating transcription factor-6 (ATF6) and cleaved Caspase-12. Moreover, ER stress suppression markedly abrogated ASP-induced apoptosis. In addition, GRP78 knockdown significantly diminished ER stress and apoptosis triggered by ASP. Importantly, co-immunoprecipitation (IP) analysis further indicated that ASP regulated the interaction between GRP78 and PERK, subsequently meditating the apoptotic cell death. In vivo leukemia xenografts finally validated ER stress and apoptosis were related to the tumor growth reduction induced by ASP. The overall survival of mice was also improved by ASP treatments, accompanied with the significantly reduced number of white blood cells and elevated red blood cells. Together, our present results showed that ASP exerted anti-leukemic effects at least partially via inducing apoptosis regulated by ER stress, and suggested that ASP might be a novel and effective therapeutic strategy for treating human leukemia.
急性髓细胞白血病（AML）是一种造血干细胞紊乱的复杂疾病。然而，其发病机制和治疗方法仍不清楚。獐牙菜苦苷（ASP）是一种裂环环烯醚萜类化合物，存在于白花蛇舌草中，是一种来自传统中药的成分。ASP 已被证明具有多种药理活性，如抗肿瘤和抗炎作用。在这项研究中，我们探讨了 ASP 对人白血病细胞和人原代白血病母细胞凋亡和内质网（ER）应激的影响。ASP 处理以剂量依赖的方式选择性地降低人白血病细胞和原代白血病母细胞的活力。我们还发现，ASP 通过促进 Caspase-9、-3 和多聚（ADP-核糖）聚合酶（PARP）的切割诱导细胞死亡，这伴随着线粒体膜电位的丧失和 Cyto-c 从线粒体释放。此外，我们发现 ASP 通过提高葡萄糖调节蛋白 78kDa（GRP78）、磷酸化蛋白激酶 RNA 样内质网激酶（PERK）、磷酸化真核翻译起始因子 2α（eIF2α）、C/EBP 同源蛋白（CHOP）、磷酸化肌醇需求酶 1（p-IRE1）、X 盒结合蛋白 1（XBP1）、激活转录因子-6（ATF6）和切割 Caspase-12 的蛋白表达水平，显著诱导白血病细胞中的 ER 应激。此外，ER 应激抑制显著阻断了 ASP 诱导的细胞凋亡。此外，GRP78 敲低显著减少了 ASP 触发的 ER 应激和细胞凋亡。重要的是，共免疫沉淀（IP）分析进一步表明，ASP 调节了 GRP78 和 PERK 之间的相互作用，从而介导了细胞凋亡。体内白血病异种移植最终验证了 ER 应激和凋亡与 ASP 诱导的肿瘤生长减少有关。ASP 治疗还改善了小鼠的总生存，伴随着白细胞数量的显著减少和红细胞的升高。总之，我们的研究结果表明，ASP 通过诱导内质网应激调控的细胞凋亡发挥抗白血病作用，并提示 ASP 可能是治疗人类白血病的一种新的有效治疗策略。
