声波刺猬信号通路通过诱导 snail 表达维持间变性甲状腺癌的癌症干细胞自我更新。
The sonic hedgehog signaling pathway maintains the cancer stem cell self-renewal of anaplastic thyroid cancer by inducing snail expression.
机构信息
Departments of General Surgery (K.B.H., X.X.) and Anatomy and Cell Biology (M.E.D., J.Y., Y.W., X.X.), Rush Medical College (A.J.W.), Chicago, Illinois 60612; Division of Endocrinology and Metabolism (D.L., M.X.), Department of Medicine, the Johns Hopkins University School of Medicine, Baltimore, Maryland 21287; and Department of Surgery (R.A.P.), NorthShore University Health System, Evanston, Illinois 60201.
出版信息
J Clin Endocrinol Metab. 2014 Nov;99(11):E2178-87. doi: 10.1210/jc.2014-1844. Epub 2014 Jul 31.
CONTEXT
Cancer stem cells (CSCs) have been recently identified in thyroid neoplasm. Anaplastic thyroid cancer (ATC) contains a higher percentage of CSCs than well-differentiated thyroid cancer. The signaling pathways and the transcription factors that regulate thyroid CSC self-renewal remain poorly understood.
OBJECTIVE
The objective of this study is to use two ATC cell lines (KAT-18 and SW1736) as a model to study the role of the sonic hedgehog (Shh) pathway in maintaining thyroid CSC self-renewal and to understand its underlying molecular mechanisms.
DESIGN
The expression and activity of aldehyde dehydrogenase (ALDH), a marker for thyroid CSCs, was analyzed by Western blot and ALDEFLUOR assay, respectively. The effect of three Shh pathway inhibitors (cyclopamine, HhAntag, GANT61), Shh, Gli1, Snail knockdown, and Gli1 overexpression on thyroid CSC self-renewal was analyzed by ALDEFLUOR assay and thyrosphere formation. The sensitivity of transfected KAT-18 cells to radiation was evaluated by a colony survival assay.
RESULTS
Western blot analysis revealed that ALDH protein levels in five thyroid cancer cell lines (WRO82, a follicular thyroid cancer cell line; BCPAP and TPC1, two papillary thyroid cancer cell lines; KAT-18 and SW1736, two ATC cell lines) correlated with the percentage of the ALDH(High) cells as well as Gli1 and Snail expression. The Shh pathway inhibitors, Shh and Gli1 knockdown, in KAT-18 cells decreased thyroid CSC self-renewal and increased radiation sensitivity. In contrast, Gli1 overexpression led to increased thyrosphere formation, an increased percentage of ALDH(High) cells, and increased radiation resistance in KAT-18 cells. Inhibition of the Shh pathway by three specific inhibitors led to decreased Snail expression and a decreased number of ALDH(High) cells in KAT-18 and SW1736. Snail gene knockdown decreased the number of ALDH(High) cells in KAT-18 and SW1736 cells.
CONCLUSIONS
The Shh pathway promotes the CSC self-renewal in ATC cell lines by Gli1-induced Snail expression.
背景
癌症干细胞（CSCs）最近在甲状腺肿瘤中被发现。间变性甲状腺癌（ATC）比分化良好的甲状腺癌含有更高比例的 CSCs。调节甲状腺 CSC 自我更新的信号通路和转录因子仍知之甚少。
目的
本研究旨在使用两种 ATC 细胞系（KAT-18 和 SW1736）作为模型，研究 sonic hedgehog（Shh）通路在维持甲状腺 CSC 自我更新中的作用，并了解其潜在的分子机制。
设计
通过 Western blot 和 ALDEFLUOR 测定分别分析醛脱氢酶（ALDH）的表达和活性，ALDH 是甲状腺 CSCs 的标志物。通过 ALDEFLUOR 测定和甲状腺球体形成分析三种 Shh 通路抑制剂（环巴胺、HhAntag、GANT61）、Shh、Gli1、Snail 敲低和 Gli1 过表达对甲状腺 CSC 自我更新的影响。通过集落存活测定评估转染的 KAT-18 细胞对辐射的敏感性。
结果
Western blot 分析显示，在五种甲状腺癌细胞系（WRO82，滤泡性甲状腺癌细胞系；BCPAP 和 TPC1，两种乳头状甲状腺癌细胞系；KAT-18 和 SW1736，两种 ATC 细胞系）中，ALDH 蛋白水平与 ALDH（High）细胞的百分比以及 Gli1 和 Snail 表达相关。KAT-18 细胞中的 Shh 通路抑制剂、Shh 和 Gli1 敲低降低了甲状腺 CSC 的自我更新能力并增加了辐射敏感性。相比之下，Gli1 过表达导致 KAT-18 细胞中甲状腺球体形成增加、ALDH（High）细胞的百分比增加和辐射抗性增加。三种特异性抑制剂抑制 Shh 通路导致 KAT-18 和 SW1736 中 Snail 表达减少和 ALDH（High）细胞数量减少。Snail 基因敲低减少了 KAT-18 和 SW1736 细胞中 ALDH（High）细胞的数量。
结论
Shh 通路通过 Gli1 诱导的 Snail 表达促进 ATC 细胞系中的 CSC 自我更新。
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