上皮细胞间质样转化对人甲状腺肿瘤干细胞发生的诱导作用

Epithelial-mesenchymal transition induces cancer stem cell generation in human thyroid cancer cells in vitro

目的论证上皮细胞间质样转化（EMT）能否诱导人甲状腺肿瘤干细胞（CSC）的发生。方法转染缺氧诱导因子（HIF）-1αeDNA诱导甲状腺癌细胞发生EMT，并以Western印迹法、免疫荧光、Transwell及四甲基偶氮唑蓝（MTr）等技术验证EMT分子特征及行为特征的变化，应用荧光激活的流式细胞分选（FACS）技术对比EMT属性变化对细胞株中干细胞分选效率的影响，并鉴定所分选细胞的“干性”分子特征及自我更新和克隆形成能力。结果转染HIF-1α成功诱导人甲状腺癌FTCl33细胞完成EMT：E一钙黏蛋白上调，波形蛋白下调，β-连环蛋白核易位，细胞体现出显著增强的体外侵袭和增殖能力。另外，EMT后的FTCl33细胞中CSC的分选效率明显升高（0．70％比0．03％，P〈0．05）。所分选细胞具有“干性”分子标志，并体现出了典型的自我更新及体外致瘤能力。结论HIF-1α能够诱导人甲状腺癌细胞完成EMT，进而促使CSC发生。

Objective Epithelial-mesenchymal transition （EMT） has been implicated in the initiation and conversion of early stage tumors into invasive malignancies and is associated with the ＂sternness＂ of cancer cells. The present study was designed to identify whether EMT induces cancer stem cell generation and tumor progression in human thyroid cancer cells in vitro. Methods FTC133 cells, as EMT-negative cells, were used for EMT induction by hypoxia-inducible factor-lot （HIF-la） transfection. And EMT features were then examined by Western blot, immunofluorescent staining, invasion and proliferation assays. Moreover, stem-like side population （SP） cells were sorted with flow cytometry from FTC133 cells before and after EMT. The proportion of SP was compared and sternness, self-renewal and tumorigenecity in vitro were identified in SP cells. Results Overexpression of HIF-loL induced FTC133 cells to undergo EMT. And it down-regulated epithelial marker E-eadherin, up-regulated mesenchymal marker vimentin and caused nucleus translocation of [3-catenin and highly invasive and metastatic properties. Most importantly, the induction of EMT promoted proportion of stem-like side population cells （0. 70% vs 0. 03%, P 〈 0. 05 ） with higher sphere formation and clone forming capability in contrast to non-side population cells. Conclusions EMT can induce cancer stem cell generation and tumor progression in thyroid cancers. Further understanding the role of EMT and cancer stem cells in cancer progression may reveal new preventive and therapeutic targets for thyroid cancers.