Aberrant differentiation of Tsc2-deficient teratomas associated with activation of the mTORC1-TFE3 pathway.
Aberrant differentiation of Tsc2-deficient teratomas associated with activation of the mTORC1-TFE3 pathway.
复制标题
与MTORC1-TFE3途径的激活相关的TSC2缺陷型Teratomas的异常分化。
DOI：
10.3892/or.2015.4254
复制
发表时间：
2015-11
期刊：
影响因子：
4.2
通讯作者：
Hino O
中科院分区：
文献类型：
--
作者：
Kawano H;Ito Y;Kanai F;Nakamura E;Tada N;Takai S;Horie S;Kobayashi T;Hino O
肾细胞癌(RCC)的模型动物Eker大鼠在结节性硬化症2(TSC2)基因上存在胚系突变。杂合突变在野生型TSC2等位基因中二次攻击形成RCC，而纯合子突变是胚胎致死的。在本研究中，建立了一种新的细胞分化模型，通过从Eker大鼠体内获得TSC2缺陷的胚胎干细胞(ESCs)来研究TSC2突变相关的发病机制。Tsc2+/+、Tsc2+/−和Tsc2−/−ESCs均能产生三层胚层：中胚层、外胚层和内胚层。有趣的是，在来自不同−/−系的TSC2ESC畸胎瘤中，可重复地观察到上皮性肿瘤样异常导管结构。免疫组织化学分析表明，在p-S6和p-4EBP1阳性染色的基础上，在TSC2−/−畸胎瘤的异常导管中，哺乳动物靶标雷帕霉素复合体1(MTORC 1)信号被激活。在这些异常的导管中，上皮性标志物(即megalin和cubilin)的表达水平以及E-钙粘附素和β-catenin的胞浆定位与Eker大鼠肾细胞癌相似。此外，在异常导管和Eker大鼠肾小管癌细胞的胞核中还发现了一个受mTORC1调控的转录因子TFE3。作为胚胎干细胞分化的负调控因子，TFE3可能导致EKER大鼠和TSC2−/−畸胎瘤中与肿瘤发生相关的组织特异性分化缺陷。本研究表明，Eker大鼠来源的ESCs是一种新的实验工具，可用于分析与TSC2缺乏相关的分化缺陷和细胞类型特异性发病机制。
The model animal of renal cell carcinoma (RCC), the Eker rat, has a germline mutation in the tuberous sclerosis 2 (Tsc2) gene. Heterozygous mutants develop RCCs by second hit in the wild-type Tsc2 allele, whereas homozygous mutants are embryonic lethal. In the present study, a new cell differentiation model was developed to study the mechanism of Tsc2 mutation-associated pathogenesis by generating Tsc2-deficient embryonic stem cells (ESCs) from Eker rats. Tsc2+/+, Tsc2+/− and Tsc2−/− ESCs were all capable of generating three germ layers: mesoderm, ectoderm, and endoderm. Interestingly, epithelial tumor-like abnormal ductal structures were reproducibly observed in Tsc2−/− teratomas from different ESC lines. Immunohistochemical analysis revealed that mammalian target of rapamycin complex 1 (mTORC1) signaling was activated in abnormal ducts of Tsc2−/− teratomas, on the basis of positive staining for p-S6 and p-4EBP1. In these abnormal ducts, expression levels of epithelial markers (i.e., megalin and cubilin) and the cytoplasmic localization of E-cadherin and β-catenin were similar to those in Eker rat RCCs. Moreover, a transcription factor regulated by mTORC1, named TFE3, was located in the nuclei of abnormal ducts and Eker rat RCCs. As a negative regulator of ESC differentiation, TFE3 may result in tissue-specific differentiation defects related to tumorigenesis in Eker rats and Tsc2−/− teratomas. The present study suggests that ESCs derived from Eker rats constitute a novel experimental tool with which to analyze differentiation defects and cell-type specific pathogenesis associated with Tsc2 deficiency.