Oncogenic Hras-dependent epidermal growth is inhibited following RNAi-mediated depletion of Ctnnb1 and Mllt6

Genome-wide RNAi screens in mice identified Ctnnb1 and Mllt6 as physiological regulators of HrasG12V-dependent epidermal hyperplasia. To probe the consequences of Ctnnb1 and Mllt6 on HrasG12V-dependent oncogenic growth, we examined how their depletion impacts gene expression in the HrasoncoX2 epidermis. We performed RNA-seq analysis of FACS-purified embryonic epidermal cells, followed by network analysis of differentially regulated transcripts. Whether Ctnnb1 or Mllt6, knockdown markedly enhanced activity of genes restricting growth, and decreased expression of genes promoting epidermal proliferation. This contrasted with known transcriptional changes that typically follow epidermal expression of oncogenic Hras. Moreover, there was a significant overlap in genes whose expression was affected by Mllt6 and β-catenin, further implying a level of shared function. Transcriptional profiles of epidermal progenitors of embryonic day 18.5 animals of wild-type, HrasG12V, and HrasG12V depleted of Ctnnb1 or Mllt6 backgrounds.

小鼠全基因组RNA干扰（RNAi）筛选表明，Ctnnb1与Mllt6是介导HrasG12V依赖性表皮增生的生理性调控因子。为探究Ctnnb1与Mllt6对HrasG12V依赖性致癌生长的影响，我们检测了二者敲低对HrasoncoX2表皮细胞基因表达的调控效应。我们对荧光激活细胞分选（FACS）纯化的胚胎表皮细胞开展了RNA测序（RNA-seq）分析，随后对差异调控转录本进行了网络分析。无论是敲低Ctnnb1还是Mllt6，均能显著增强生长抑制基因的活性，并下调促进表皮增殖的基因的表达。该结果与致癌Hras在表皮中表达后通常出现的已知转录变化形成显著反差。此外，受Mllt6与β-连环蛋白（β-catenin）调控的基因存在显著表达重叠，进一步提示二者存在功能共通性。本数据集涵盖胚胎第18.5天的野生型、HrasG12V突变型，以及HrasG12V背景下敲低Ctnnb1或Mllt6的小鼠表皮祖细胞的转录谱。