The Wnt/β-catenin pathway regulates self-renewal of cancer stem-like cells in human gastric cancer
The Wnt/β-catenin pathway regulates self-renewal of cancer stem-like cells in human gastric cancer
复制标题
DOI：
10.3892/mmr.2012.802
复制
发表时间：
2012-05-01
影响因子：
3.4
通讯作者：
Zhu, Xiaohan
中科院分区：
文献类型：
--
作者：
Cai, Chen;Zhu, Xiaohan
肿瘤干细胞(CSCs)具有自我更新和启动肿瘤的能力。靶向在CSC自我更新中活跃的关键信号通路是癌症治疗的一种方法。Wnt/β-catenin通路在多种人类癌症和CSCs中的异常激活已被描述，但该途径在胃CSCs中的作用尚未见报道。在我们的研究中，我们研究了Wnt/β-catenin途径是否在胃CSCs中发挥重要作用。首先，我们使用肿瘤球体培养从人胃癌细胞系MKN-45中分离出癌症干细胞(CSLC)。我们使用以下三个标准来检测肿瘤球细胞是否为CSLC：i)我们发现CSC标记物CD44在肿瘤球细胞中的表达明显高于贴壁细胞；ii)与贴壁细胞相比，漂浮的肿瘤球细胞具有更强的自我更新能力；iii)体内异种移植研究表明，在相同数量的肿瘤球细胞中，肿瘤细胞比贴壁细胞产生更大的肿瘤。此外，我们还研究了规范的Wnt信号通路在CSLCs中的作用机制(S)。Western blotting和实时定量聚合酶链式反应(Real-Time-PCR)显示，随着Wnt通路的抑制/激活，β-catenin和c-myc、细胞周期蛋白D1和Axin 2的表达水平下调/上调。DKK-1阻断的途径使MKN-45肿瘤细胞的自我更新能力降低，而氯化锂激活的途径促进了CSLCs的自我更新。综上所述，我们的研究结果提示，Wnt/β-catenin通路对于人胃癌CSLCs的自我更新是必不可少的。
Cancer stem cells (CSCs) possess the ability of self-renewal and tumor initiation. Targeting key signaling pathways that are active in CSC self-renewal is one approach to cancer therapy. Abnormal activation of the Wnt/beta-catenin pathway has been described in a wide variety of human cancers and in CSCs; however, the role of this pathway in gastric CSCs has not been reported. In our study, we investigated whether the Wnt/beta-catenin pathway plays an important role in gastric CSCs. First, we isolated cancer stem-like cells (CSLCs) from the human gastric cancer cell line MKN-45 using tumorsphere cultures. We tested whether tumorsphere cells were CSLCs using the following three criteria: i) We identified that the expression of the CSC marker CD44 was significantly greater in tumorsphere cells compared to adherent cells; ii) compared with adherent cells, the floating tumorsphere cells had greater self-renewing capacity; iii) in vivo xenograft studies showed that tumorsphere cells generate larger tumors than adherent cells at the same number. In addition, we studied the mechanism(s) by which the canonical Wnt signaling pathway acts in CSLCs. Western blotting and real-time PCR showed that the expression levels of beta-catenin and c-myc, cyclin d1 and axin 2 were downregulated/upregulated with the inhibition/activation of the Wnt pathway. The pathway blocked by DKK-1 caused a higher reduction in the self-renewing capacity of MKN-45 tumorsphere cells and the pathway activated by lithium chloride improved the self-renewal of CSLCs. In conclusion, our data suggested that the Wnt/beta-catenin pathway is essential for the self-renewal of CSLCs in human gastric cancer.