NRASG12V mediates self renewal in AML [RNA-Seq]

Mutant RAS oncoproteins activate signaling molecules that drive oncogenesis in multiple human tumors including acute myelogenous leukemia (AML). However, the specific function of these pathways in AML is unclear. To elucidate the downstream functions of activated NRAS in AML, we employed a murine model of AML harboring Mll-AF9 and NRASG12V. We found that NRASG12V enforced leukemia self-renewal gene expression signatures and was required to maintain an MLL-AF9 and MYB-dependent gene expression program. In a multiplexed analysis of RAS-dependent signaling intermediates, the leukemia stem cell compartment was preferentially sensitive to RAS withdrawal. Use of RAS-pathway inhibitors showed that NRASG12V maintained leukemia self-renewal through mTOR and MEK pathway activation, implicating these pathways as potential targets for cancer stem cell-specific therapies. Primary NRASG12V-Mll-AF9 AML cells were treated in vitro for 24 hours with Ras-pathway inhibitors. RNA was extracted from these cells and submitted for RNA sequencing.

突变型RAS癌蛋白可激活信号分子，进而驱动包括急性髓系白血病（acute myelogenous leukemia, AML）在内的多种人类肿瘤发生发展。然而，此类通路在急性髓系白血病中的具体功能仍未明确。
为阐明激活型NRAS在急性髓系白血病中的下游功能，我们采用了携带Mll-AF9与NRASG12V突变的急性髓系白血病小鼠模型。研究发现，NRASG12V可强化白血病自我更新相关基因的表达特征，且对于维持MLL-AF9与MYB依赖的基因表达程序必不可少。
在针对RAS依赖型信号通路中间分子的多重分析中，白血病干细胞（leukemia stem cell）亚群对RAS撤除表现出优先敏感性。通过使用RAS通路抑制剂开展实验，我们发现NRASG12V可通过激活mTOR与MEK通路维持白血病自我更新能力，提示上述通路可作为癌症干细胞（cancer stem cell）特异性治疗的潜在靶点。
我们对原代NRASG12V-Mll-AF9急性髓系白血病细胞进行了24小时的体外RAS通路抑制剂处理，随后提取上述细胞的总RNA，并提交进行RNA测序（RNA sequencing）。