Department of Clinical and Molecular Medicine, University of Rome La Sapienza, S Andrea Hospital, Rome, Italy.
J Cell Physiol. 2013 Aug;228(8):1720-6. doi: 10.1002/jcp.24300.
Epithelial-to-mesenchymal transition (EMT) is a process in which cells undergo a developmental switch from epithelial to mesenchymal phenotype. This process has been related to embryologic morphogenesis but also to cancer progression and metastasis. The aim of the current study was to investigate the expression of EMT-related markers in adherent and spheroid cell cultures derived from malignant pleural effusions (MPEs) of patients affected by lung adenocarcinoma. On the basis of efficient in vitro propagation, six cases of MPEs were selected and analyzed by immunocytochemistry staining for EMT markers and by RT-PCR for transcription factors known to orchestrate EMT. EMT markers immunostaining showed in spheroids a statistically significant correlation between the loss of E-cadherin immunoreactivity and overexpression of N-cadherin (P < 0.001). Likewise loss of EpCAM epithelial marker was coincident with Vimentin overexpression (P < 0.001). RT-PCR analysis of transcription factors Snail, Slug, and Twist showed a highly variable expression, although a general trend to increase was observed. Importantly, in some selected cases it was possible to establish a precise relationship between spheroid formation, EMT switch and increased upregulation of the marker related to cancer stemness such as ALDH positivity. Therefore, MPE-derived cell cultures, while recapitulating the heterogeneity of lung cancer, are a suitable system to study the mechanisms at the basis of EMT and to understand its relationship with the generation of cancer stem cells.
上皮-间充质转化（EMT）是细胞从上皮表型向间充质表型发生发育转变的过程。这个过程与胚胎形态发生有关，但也与癌症的进展和转移有关。本研究的目的是研究 EMT 相关标志物在来源于肺腺癌患者恶性胸腔积液（MPE）的贴壁细胞和球体培养物中的表达。基于有效的体外增殖，选择了 6 例 MPE 进行分析，通过免疫细胞化学染色检测 EMT 标志物，通过 RT-PCR 检测已知参与 EMT 调控的转录因子。免疫细胞化学染色显示，在球体中，E-钙黏蛋白免疫反应性的丧失与 N-钙黏蛋白的过度表达之间存在统计学显著相关性（P<0.001）。同样，上皮标志物 EpCAM 的丢失与波形蛋白的过度表达相一致（P<0.001）。转录因子 Snail、Slug 和 Twist 的 RT-PCR 分析显示表达高度可变，尽管观察到总体趋势是增加。重要的是，在一些选定的情况下，有可能在球体形成、EMT 转换和与癌症干细胞相关标志物（如 ALDH 阳性）的上调之间建立精确的关系。因此，MPE 来源的细胞培养物虽然再现了肺癌的异质性，但却是研究 EMT 基础机制以及理解其与癌症干细胞生成关系的合适系统。
