Zhang Yong, Wen Yu-Lin, Ma Ji-Wei, Ye Jie-Cheng, Wang Xiao, Huang Jian-Xian, Meng Chao-Yue, Xu Xiao-Ze, Wang Shao-Xiang, Zhong Xue-Yun
Department of Pathology, Medical School of Jinan University, Guangzhou, Guangdong 510632, P.R. China.
Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou, Guangdong 510632, P.R. China.
Int J Oncol. 2017 Jan;50(1):101-110. doi: 10.3892/ijo.2016.3780. Epub 2016 Nov 23.
Cancer stem cells (CSCs) in glioma are often responsible for relapse and resistance to therapy. The purpose of the present study was to confirm the self-renewal and migration inhibitory effects of tetrandrine (Tet), which is a compound extracted from the dried root of Stephania tetrandra S. Moore, toward glioma stem-like cells (GSLCs) and to examine the associated molecular mechanisms. Using a neurosphere culture technique, we enriched the GSLC population from the human glioblastoma cell lines U87 and U251. Cells were analyzed using cell counting kit-8 (CCK-8), western blotting, flow cytometry, transwell assay and immunofluorescence staining. GSLCs displayed properties of neural stem cells, including elevated expression of the cancer stem cell marker ALDH1 and β-catenin. We found that Tet treatment decreased sphere formation in GSLCs in a dose-dependent manner using tumor spheroid formation assay. The GSK3β inhibitor BIO maintained sphere formation and migration capacity in GSLCs, whereas the β-catenin/TCF transcription inhibitor ICG-001 decreased sphere formation and the migration capacity of GSLCs. The proportion of apoptotic GSLCs also increased in response to ICG-001 treatment. These results indicate that β-catenin activity is vital in maintaining neural stem cell traits of GSLCs. Tet inhibits cell viability, neurosphere formation and migration of GSLCs in vitro. Importantly, Tet treatment significantly repressed the nuclear translocation and expression of β-catenin and induced apoptosis in GSLCs, as indicated in part by the upregulation of Bax, the cleavage of PARP and the downregulation of Bcl-2. The present study demonstrates that the inhibition of β-catenin in CSCs by Tet could be an effective strategy for the treatment of glioma.
胶质瘤中的癌症干细胞（CSCs）通常是复发和治疗耐药的原因。本研究的目的是证实粉防己碱（Tet）对胶质瘤干细胞样细胞（GSLCs）的自我更新和迁移抑制作用，并探讨相关的分子机制。粉防己碱是从防己干燥根中提取的一种化合物。我们使用神经球培养技术从人胶质母细胞瘤细胞系U87和U251中富集GSLC群体。使用细胞计数试剂盒-8（CCK-8）、蛋白质免疫印迹法、流式细胞术、Transwell实验和免疫荧光染色对细胞进行分析。GSLCs表现出神经干细胞的特性，包括癌症干细胞标志物醛脱氢酶1（ALDH1）和β-连环蛋白的表达升高。我们发现，使用肿瘤球形成实验，Tet处理以剂量依赖的方式减少了GSLCs中的球形成。糖原合成酶激酶3β（GSK3β）抑制剂BIO维持了GSLCs中的球形成和迁移能力，而β-连环蛋白/TCF转录抑制剂ICG-001降低了GSLCs的球形成和迁移能力。ICG-001处理后，凋亡的GSLCs比例也增加。这些结果表明，β-连环蛋白活性对于维持GSLCs的神经干细胞特性至关重要。Tet在体外抑制GSLCs的细胞活力、神经球形成和迁移。重要的是，Tet处理显著抑制了β-连环蛋白的核转位和表达，并诱导了GSLCs的凋亡，部分表现为Bax上调、聚ADP核糖聚合酶（PARP）裂解和Bcl-2下调。本研究表明，Tet抑制CSCs中的β-连环蛋白可能是治疗胶质瘤的有效策略。
