Zhao Ran, Choi Bu Young, Wei Lixiao, Fredimoses Mangaladoss, Yin Fanxiang, Fu Xiaorong, Chen Hanyong, Liu Kangdong, Kundu Joydeb Kumar, Dong Zigang, Lee Mee-Hyun
Department of Pathophysiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China.
China-US (Henan) Hormel Cancer Institute, Zhengzhou, China.
Br J Pharmacol. 2020 May;177(10):2303-2319. doi: 10.1111/bph.14981. Epub 2020 Apr 10.
Overexpression or aberrant activation of the T-lymphokine-activated killer cell-originated protein kinase (TOPK) promotes gene expression and growth of solid tumours, implying that TOPK would be a rational target in developing novel anticancer drugs. Acetylshikonin, a diterpenoid compound isolated from Lithospermum erythrorhizon root, exerts a range of biological activities. Here we have investigated whether acetylshikonin, by acting as an inhibitor of TOPK, can attenuate the proliferation of colorectal cancer cells and the growth of patient-derived tumours, in vitro and in vivo.
Targets of acetylshikonin, were identified using kinase profiling analysis, kinetic/binding assay, and computational docking analysis and knock-down techniques. Effects of acetylshikonin on colorectal cancer growth and the underlying mechanisms were evaluated in cell proliferation assays, propidium iodide and annexin-V staining analyses and western blots. Patient-derived tumour xenografts in mice (PDX) and immunohistochemistry were used to assess anti-tumour effects of acetylshikonin.
Acetylshikonin directly inhibited TOPK activity, interacting with the ATP-binding pocket of TOPK. Acetylshikonin suppressed cell proliferation by inducing cell cycle arrest at the G1 phase, stimulated apoptosis, and increased the expression of apoptotic biomarkers in colorectal cancer cell lines. Mechanistically, acetylshikonin diminished the phosphorylation and activation of TOPK signalling. Furthermore, acetylshikonin decreased the volume of PDX tumours and reduced the expression of TOPK signalling pathway in xenograft tumours.
Acetylshikonin suppressed growth of colorectal cancer cells by attenuating TOPK signalling. Targeted inhibition of TOPK by acetylshikonin might be a promising new approach to the treatment of colorectal cancer.
T淋巴细胞激活的杀伤细胞源蛋白激酶（TOPK）的过表达或异常激活会促进实体瘤的基因表达和生长，这表明TOPK可能是开发新型抗癌药物的合理靶点。乙酰紫草素是从紫草根部分离出的一种二萜类化合物，具有多种生物学活性。在此，我们研究了乙酰紫草素作为TOPK抑制剂，在体外和体内能否抑制结肠癌细胞的增殖以及患者来源肿瘤的生长。
使用激酶谱分析、动力学/结合分析、计算对接分析和基因敲除技术来确定乙酰紫草素的作用靶点。通过细胞增殖试验、碘化丙啶和膜联蛋白V染色分析以及蛋白质免疫印迹法评估乙酰紫草素对结肠癌生长的影响及其潜在机制。利用小鼠体内患者来源的肿瘤异种移植模型（PDX）和免疫组织化学方法来评估乙酰紫草素的抗肿瘤作用。
乙酰紫草素直接抑制TOPK活性，与TOPK的ATP结合口袋相互作用。乙酰紫草素通过诱导细胞周期停滞在G1期来抑制细胞增殖，刺激细胞凋亡，并增加结肠癌细胞系中凋亡生物标志物的表达。从机制上讲，乙酰紫草素减少了TOPK信号的磷酸化和激活。此外，乙酰紫草素减小了PDX肿瘤的体积，并降低了异种移植肿瘤中TOPK信号通路的表达。
乙酰紫草素通过减弱TOPK信号来抑制结肠癌细胞的生长。乙酰紫草素对TOPK的靶向抑制可能是一种有前景的治疗结肠癌的新方法。
