Wilms肿瘤是婴幼儿泌尿生殖系统最常见的恶性实体肿瘤，其中仅三分之一明确是由WT1基因突变所致且多为预后良好型；且70%的Wilms肿瘤伴有Igf2过表达的表观遗传特点。目前只有WT1基因敲除Igf2上调表达的小鼠Wilms肿瘤模型。近年临床数据表明Six1基因突变可能是预后不良型Wilms肿瘤的主要原因。本课题组研究发现，Six1基因敲除猪早期胎儿出现肾祖细胞分化受到抑制和间充质-上皮转化过程受阻等Wilms肿瘤发生倾向。本研究拟利用CRISPR/Cas9技术构建Six1基因敲除同时上调表达Igf2基因的巴马小型猪模型；证实Six1基因敲除诱发Wilms肿瘤的可能性，并揭示预后不良型Wilms肿瘤发生的分子机制；利用细胞培养和分子手段探讨Six1基因在Wilms肿瘤发生和肾脏发育调节中的相关信号通路。该项目可以为临床上预后不良型Wilms肿瘤的预防、治疗和靶向药物筛选提供大动物模型。

Wilms tumor is a childhood kidney tumor. Only one third of the Wilms tumors were confirmed to be resulted from WT1 gene mutation and this type of tumors are not high risk. The epigenetic character with biallelic expression of Igf2 was observed in approximate 70% Wilms tumors. Until now, there are only mouse model with WT1 knocked-out and Igf2 over-expressed for Wilms tumor. The recent clinic data shown that Six1(sine oculis homeobox 1) pathway might underlie the high risk type Wilms tumors. In our previous study, the trends of Wilms tumor formation, such as the suppression of the nephrogenic progenitor differentiation and the block of mesenchymal-epithelial transition, were observed in kidney of Day 75 Six1-/- pig fetuses. In this project, the CRISPR/Cas9 technology will be used to produce transgenic cloned Bama miniature pig model with Six1 gene knocked-out and Igf2 over-expressed. The feasibility to induce Wilms tumor via Six1 gene deletion will be evaluated. The roles and molecular mechanisms of Six1 gene in Wilms tumorigenesis will be investigated. In addition, the Wilms tumor related signal pathway and the kidney development related signal pathway will be studied via cell culture and molecular technologies in vitro. This study will provide an effective large animal model for the prevention and targeted therapy of high risk type Wilms tumor with poor prognosis.