Either Kras activation or Pten loss similarly enhance the dominant-stable CTNNB1-induced genetic program to promote granulosa cell tumor development in ovary and testis

Stable activation of the WNT signaling effector beta-catenin (CTNNB1(ex3) in ovarian granulosa cells results in the formation of premalignant lesions that develop into granulosa cell tumors (GCTs) spontaneously later in life. Loss of the tumor suppressor gene Pten accelerates GCT formation in the CTNNB1 strain. Conversely, expression of oncogenic KRASG12D causes the dramatic arrest of proliferation, differentiation and apoptosis in granulosa cells, and consequently, small abnormal follicle-like structures devoid of oocytes accumulate in the ovary. Because of the potent anti-proliferative effects of KRASG12D in granulosa cells, we sought to determine if KRASG12D would block precancerous lesion and tumor formation in follicles of the CTNNB1 mutant mice. Unexpectedly, transgenic Ctnnb1;Kras mutant mice developed early-onset GCTs leading to premature death in a manner similar to theCtnnb1;Pten mutant mice. Moreover, the GCTs in the Ctnnb1;Kras mutant mice exhibited increased GC proliferation, decreased apoptosis and impaired differentiation. Microarray and RT-PCR analyses revealed that ovaries from mice expressing dominant-stable CTNNB1 with either Pten loss or KRAS activation were unpredictably similar. Specifically, gene regulatory processes induced by CTNNB1 were mostly enhanced by either KRAS activation or Pten loss in remarkably similar patterns and degree. Furthermore, the concomitant activation of CTNNB1 and KRAS in Sertoli cells resulted in the development of granulosa cell tumors of the testis. RT-PCR studies showed a partial overlap in gene regulatory processes associated with tumor development in the ovary and testis. Together, these results suggest that KRAS activation and Pten loss induce GCT development from premalignant lesions via highly similar molecular mechanisms. four samples: average of two wild type samples (previously submitted as GSM403220 and GSM403221), beta-Catenin constitutively active mutant, beta-Catenin;Pten double mutant, and beta-Catenin;Kras(G12D) double mutant卵巢颗粒细胞中WNT信号通路效应因子β-连环蛋白（beta-catenin，CTNNB1(ex3)）的稳定激活，可诱导癌前病变形成，该病变会在小鼠晚年自发进展为颗粒细胞瘤（GCTs）。肿瘤抑制基因PTEN的缺失会加速CTNNB1突变小鼠品系中GCT的形成。与之相反，致癌突变KRASG12D的表达会显著阻滞颗粒细胞的增殖、分化与凋亡，进而导致卵巢中积累大量不含卵母细胞的异常小型滤泡样结构。鉴于KRASG12D在颗粒细胞中具有强效的抗增殖作用，本研究旨在探究KRASG12D是否能够阻滞CTNNB1突变小鼠卵泡内的癌前病变与肿瘤形成。出乎意料的是，双转基因Ctnnb1;Kras突变小鼠会提早出现GCT，并因此过早死亡，其表型与Ctnnb1;Pten突变小鼠相似。此外，Ctnnb1;Kras突变小鼠的GCTs表现出颗粒细胞增殖增强、凋亡减少以及分化受损的特征。微阵列（Microarray）与逆转录聚合酶链反应（RT-PCR）分析显示，同时表达显性稳定CTNNB1且伴随PTEN缺失或KRAS激活的小鼠卵巢，其转录谱存在出人意料的相似性。具体而言，由CTNNB1诱导的基因调控过程，在KRAS激活或PTEN缺失的情况下均得到显著增强，且增强模式与程度高度相似。进一步研究发现，在支持细胞（Sertoli cells）中同时激活CTNNB1与KRAS，会诱导睾丸出现颗粒细胞瘤。RT-PCR实验结果显示，卵巢与睾丸中与肿瘤发生相关的基因调控过程存在部分重叠。综上，上述结果表明，KRAS激活与PTEN缺失可通过高度相似的分子机制，从癌前病变诱导GCT的发生发展。本数据集共包含4组样本：两组野生型样本（此前提交编号为GSM403220与GSM403221）的均值、β-连环蛋白组成型激活突变样本、β-连环蛋白;PTEN双突变样本，以及β-连环蛋白;Kras(G12D)双突变样本。