Persistent SIX2 expression as a first hit mechanism in Wilms tumorigenesis

SIX2 持续表达是肾母细胞瘤发生中的第一击机制

• 批准号: 9248187
• 负责人: Harold Newton Lovvorn
• 金额: $ 3.36万
• 依托单位: VANDERBILT UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-12-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9248187
• 关键词: Persistent; SIX2; expression; first; hit

DESCRIPTION (provided by applicant): Wilms tumor (WT) is a pediatric renal malignancy thought to arise from persistence and aberrant differentiation of embryonic kidney stem cells. Precisely how nephron progenitors escape pathways of epithelial commitment and conversion, mechanisms that potentially represent "first hits" in Wilms tumorigenesis, have not been clarified. WT blastema, the putative malignant analogue of these nephron progenitors, retains expression of the transcriptional regulator, SIX2, which in mouse development promotes self-renewal of the cap mesenchyme (CM) and prevents premature epithelial differentiation. Our previous work has shown that SIX2, normally absent in the adult kidney, is persistently expressed across a broad spectrum of human WT. Putting together these observations of SIX2 activity in development and disease, the fundamental question arises whether this gene provides a mechanism for the CM and its progeny to self-perpetuate in the WT sequence. The purpose of developing this mouse model is to test the hypothesis that persistent expression of SIX2 in the CM impairs epithelial differentiation, and promotes retention of this progenitor population and development of nephrogenic rests, the putative precursor lesion of WT. We have two aims: 1) To generate and validate a tetracycline-regulated transgenic mouse line that allows temporal control of SIX2 expression in the embryonic kidney, and 2) To characterize the phenotype of persistent SIX2 expression in the embryonic and adult kidney. A founder transgenic mouse line will be engineered to express SIX2 persistently under the control of a tetracycline response element (TRE-RFP-2A-SIX2). Once validated, this mouse will be crossed with the ROSA26-M2-rtTA line, which provides global and constitutive expression of rtTA (Tet-On). Doxycycline will be administered to dams at e15.5 to activate SIX2 transgene expression, and its effects on CM differentiation and persistence will be evaluated. Persistence of CM cells within the post-natal kidney resembling nephrogenic rests is the anticipated phenotype. These pilot studies will lay the foundation for future, more definitive investigation targeting persisten SIX2 expression to the CM only. These future studies will use the CM-specific CITED1-Cre-ERT2 mouse engineered previously in our laboratory.

描述（由申请人提供）：Wilms肿瘤（WT）是一种儿科肾脏恶性肿瘤，认为是由于胚胎肾脏干细胞的持久性和异常分化而引起的。尚未尚未阐明肾上腺祖细胞如何逃脱上皮承诺和转化的途径，即可能代表威尔姆斯肿瘤发生中“首先命中”的机制。 WT BLASTEMA是这些肾单位祖细胞的假定恶性类似物，保留了转录调节剂Six2的表达，在小鼠发育中，它促进了帽间质（CM）的自我更新，并防止早产上皮分化。我们以前的工作表明，通常在成年肾脏中缺乏的六个持续在人类WT中持续表达。将这些对六个活性在发育和疾病中的观察汇总在一起时，基本问题出现了该基因是否为CM及其后代提供了一种在WT序列中进行自我的机制。开发该小鼠模型的目的是检验以下假设：CM在CM中的持续表达会损害上皮分化，并促进该祖细胞种群的保留和肾原性的发展，这是WT的假定前体病变。我们有两个目的：1）生成和验证四环素调节的转基因小鼠系，该系列允许对胚胎肾脏中的Six2表达进行时间控制，而2）表征胚胎和成人肾脏中持续的SIX2表达的表型。创始人的转基因小鼠系将被设计为在四环素响应元件（TRE-RFP-2A-SIX2）的控制下持续表达六2。一旦验证，该鼠标将与Rosa26-M2-RTTA线交叉，该线提供RTTA（TET-ON）的全局和本构表达。强力霉素将以E15.5的高度施用，以激活Six2转基因表达，并将评估其对CM分化和持久性的影响。在产后肾脏中类似于肾原性休息的CM细胞的持久性是预期的表型。这些试点研究将为未来，更明确的调查奠定基础，该研究仅针对CM持续六个表达。这些未来的研究将使用以前在我们实验室中设计的CM特异性引用的1-CRE-ERT2小鼠。