State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Exp Hematol. 2010 Mar;38(3):191-201. doi: 10.1016/j.exphem.2009.12.005. Epub 2010 Jan 4.
Eriocalyxin B (EriB) is a natural diterpenoid purified from Isodon eriocalyx var. laxiflora and possesses strong antileukemic activity. In this study, we further investigated its effect and mechanism of action in human lymphoma.
In vitro, a series of B- and T-lymphoma cells were treated with EriB. Cell apoptosis was analyzed using flow cytometric assay. Expression of proteins related to apoptosis and cell signal transduction were assessed using Western blot. In vivo antitumor activity of EriB was examined in murine xenograft B- and T-lymphoma models, with in situ cell apoptosis detected by terminal deoxytransferase-catalyzed DNA nick-end labeling assay.
EriB significantly inhibited lymphoma cell proliferation and induced apoptosis in association with caspase activation. Antiapoptotic Bcl-2 family members Bcl-2 and Bcl-xL were downregulated, with proapoptotic member Bax stable or upregulated, resulting in reduced Bcl-2/Bax and Bcl-xL/Bax ratios. Meanwhile, multiple signal transduction pathways were involved in lymphoma cell apoptosis in response to EriB, including inhibition of nuclear factor (NF)-kappaB and AKT pathways, and the activation of extracellular signal-related kinase (ERK) pathway. AKT inactivation was related to increased expression of cyclin-dependent kinase inhibitor P21, decreased expression of antiapoptotic phosphorylated form of Bad, and NF-kappaB activator IkappaB kinase alpha/beta. ERK activation corresponded to reactive oxygen species production and could be blocked by antioxidant dithiothreitol. In murine xenograft lymphoma models, EriB remarkably inhibited tumor growth and induced in situ tumor cell apoptosis.
These findings broaden the value of EriB as a promising candidate targeting apoptosis cascade in treatment of hematological malignancies.
从秀丽艾纳香中分离得到的天然二萜类化合物埃里卡林 B（EriB）具有很强的抗白血病活性。本研究进一步探讨了其在人淋巴瘤中的作用和机制。
在体外，用一系列 B 和 T 淋巴瘤细胞处理 EriB。用流式细胞术分析细胞凋亡。用 Western blot 检测与细胞凋亡和细胞信号转导相关的蛋白表达。用原位末端脱氧核苷酸转移酶催化的 DNA 缺口末端标记法检测埃里卡林 B 在小鼠异种移植 B 和 T 淋巴瘤模型中的体内抗肿瘤活性。
EriB 显著抑制淋巴瘤细胞增殖，并与半胱天冬酶激活诱导细胞凋亡有关。抗凋亡 Bcl-2 家族成员 Bcl-2 和 Bcl-xL 下调，促凋亡成员 Bax 稳定或上调，导致 Bcl-2/Bax 和 Bcl-xL/Bax 比值降低。同时，EriB 诱导淋巴瘤细胞凋亡涉及多种信号转导通路，包括核因子（NF）-kappaB 和 AKT 通路的抑制，以及细胞外信号相关激酶（ERK）通路的激活。AKT 失活与细胞周期蛋白依赖性激酶抑制剂 P21 的表达增加、抗凋亡磷酸化 Bad 表达减少以及 NF-kappaB 激活剂 IkappaB 激酶 alpha/beta 有关。ERK 激活与活性氧的产生有关，抗氧化剂二硫苏糖醇可阻断其激活。在小鼠异种移植淋巴瘤模型中，EriB 显著抑制肿瘤生长并诱导原位肿瘤细胞凋亡。
这些发现拓宽了 EriB 作为一种有前途的候选药物的价值，可靶向治疗血液恶性肿瘤中的凋亡级联反应。
