Department of Cell Biology, Maria Curie-Sklodowska University, Akademicka 19, 20-033 Lublin, Poland.
Department of Virology and Immunology, Maria Curie-Sklodowska University, Akademicka 19, 20-033 Lublin, Poland.
Biochim Biophys Acta Gen Subj. 2019 Nov;1863(11):129408. doi: 10.1016/j.bbagen.2019.08.001. Epub 2019 Aug 3.
Xanthohumol (XN, a hop-derived prenylflavonoid) was found to exert anticancer effects on various cancer types. However, the mechanisms by which XN affects the survival of multiple myeloma cells (MM) are little known. Therefore, our study was undertaken to address this issue.
Anti-proliferative activity of XN towards two phenotypically distinct MM cell lines U266 and RPMI8226 was evaluated with the MTT and BrdU assays. Cytotoxicity was determined with the LDH method, whereas apoptosis was assessed by flow cytometry and fluorescence staining. The expression of cell cycle- and apoptosis-related proteins and the activation status of signaling pathways were estimated by immunoblotting and ELISA assays.
XN reduced the viability of RPMI8226 cells more potently than in U266 cells. It blocked cell cycle progression through downregulation of cyclin D1 and increased p21 expression. The marked apoptosis induction in the XN-treated RPMI8226 cells was related to initiation of mitochondrial and extrinsic pathways, as indicated by the altered p53, Bax, and Bcl-2 protein expression, cleavage of procaspase 8 and 9, and elevated caspase-3 activity. The apoptotic process was probably mediated via ROS overproduction and MAPK (ERK and JNK) activation as N-acetylcysteine, or specific inhibitors of these kinases prevented the XN-induced caspase-3 activity and, hence, apoptosis. Moreover, XN decreased sIL-6R and VEGF production in the studied cells.
ERK and JNK signaling pathways are involved in XN-induced cytotoxicity against MM cells.
The advanced understanding of the molecular mechanisms of XN action can be useful in developing therapeutic strategies to treat multiple myeloma.
黄腐酚（XN，一种源自啤酒花的类异戊二烯黄酮）已被发现对多种癌症类型具有抗癌作用。然而，XN 影响多发性骨髓瘤细胞（MM）存活的机制知之甚少。因此，我们进行了这项研究。
用 MTT 和 BrdU 测定法评估 XN 对两种表型不同的 MM 细胞系 U266 和 RPMI8226 的抗增殖活性。用 LDH 法测定细胞毒性，而用流式细胞术和荧光染色法评估细胞凋亡。通过免疫印迹和 ELISA 测定法评估细胞周期和凋亡相关蛋白的表达以及信号通路的激活状态。
XN 降低 RPMI8226 细胞的活力比 U266 细胞更有效。它通过下调细胞周期蛋白 D1 和增加 p21 表达来阻止细胞周期进程。XN 处理的 RPMI8226 细胞中明显的凋亡诱导与线粒体和外在途径的启动有关，如 p53、Bax 和 Bcl-2 蛋白表达的改变、procaspase 8 和 9 的裂解以及 caspase-3 活性的升高所示。凋亡过程可能通过 ROS 过度产生和 MAPK（ERK 和 JNK）激活介导，因为 N-乙酰半胱氨酸或这些激酶的特异性抑制剂可防止 XN 诱导的 caspase-3 活性，从而防止凋亡。此外，XN 降低了研究细胞中 sIL-6R 和 VEGF 的产生。
ERK 和 JNK 信号通路参与了 XN 诱导的 MM 细胞毒性。
对 XN 作用的分子机制的深入了解可用于开发治疗多发性骨髓瘤的治疗策略。
