Effects of mutation of the LH/CG- receptor on its signaling activity

在睾丸肿瘤患者中发现LH/CG-R存在生殖系和体细胞激活突变，提出了其（突变的LH/CG-R）潜在致瘤作用的问题。 两名患者的激活突变Asp 578 Gly突变发展间质细胞瘤，而体细胞Asp 578 His激活突变被确定在一些睾丸肿瘤患者。 迄今为止，动物研究未能建立携带LH/CG-R的雄性或雌性转基因创始小鼠品系，其Asp 578 His突变指示生殖系和体细胞突变之间的固有差异。 为了探讨两种突变之间的生物学效应的差异，通过稳定转染两种突变的人受体LH/CG-R-Asp 578 Gly和LH/CG-R-Asp 578 His来建立MA-10 Leydig细胞模型。利用cDNA微阵列和系统生物学方法对基因表达谱进行检测，通过系统聚类和多维尺度分析，可以区分野生型和两种突变体。 LH/CG-R Asp 578 Gly突变改变了54个基因的表达，而LH/CG-R Asp 578 His突变改变了49个基因的表达。 通过比较两种突变体与野生型，发现132个基因差异表达。确定了每种突变特有的新调控途径; LH/CG-R-Asp 578 Gly表达细胞中有9个网络，LH/CG-R-Asp 578 His表达细胞中有12个网络。 进一步的分析表明c-Myc和c-Src分别是与Asp 578 Gly和Asp 578 His突变体相关的关键调节因子。 这两个因素的参与，证实了分子和功能测定。 这些结果为LH/CG-R突变在睾丸肿瘤发生中的作用开辟了一个新的维度，并提供了新的解释。

Discovery of the presence of LH/CG-R with germline and somatic activating mutations in patients with testicular tumor raised the question of its (mutated LH/CG-R) potential tumorigenic effect . Two patients with the activating mutation Asp578Gly mutation developed Leydig cell neoplasia, while a somatic Asp578His activating mutation was identified in a number of testicular tumor patients. Animal studies have so far failed to establish lines of male or female transgenic founder mice carrying LH/CG-R with the Asp578His mutation indicative of inherent differences between the germline and the somatic mutations. To explore the difference in the biological effects between the two mutations, a MA-10 Leydig cell model was established by stable transfection with the two mutant human receptors, LH/CG-R-Asp578Gly and LH/CG-R-Asp578His. Examination of gene expression profiles using cDNA microarray and a systems biological approach, hierarchical clustering and multi-dimensional scaling analysis , the wild type and the two mutants could be distinguished . The expression of 54 genes was altered by the presence of LH/CG-R Asp578Gly mutation, while 49 genes were changed in the presence of the LH/CG-R Asp578His mutation. By comparing both mutants to the wild type, 132 genes were found to be differentially expressed. Novel regulatory pathways unique to each mutation were identified; 9 networks in LH/CG-R-Asp578Gly expressing cells, and 12 in LH/CG-R-Asp578His expressing cells. Further analyses showed c-Myc and c-Src to be the key regulators associated with Asp578Gly and Asp578His mutants, respectively. The involvement of these two factors was confirmed by molecular and functional assays. The results open a new dimension and provide a novel explanation for the role of LH/CG-R mutation in testicular tumorigenesis.