Novel effectors of Kras in oncogenesis, senescence and tumor progression

描述(申请人提供)：KRAS是最常发生突变的人类癌基因之一。在某些情况下，致癌的KRAS可以引发细胞衰老，而在另一些情况下，KRAS的表达会导致过度增殖。鉴于KRAS突变在人类癌症中的重要性，阐明调节这两种截然不同的结果的机制将有助于确定RAS驱动的癌症的新治疗方法。我们已经确定Wilms Tumor-1(WT1)作为致癌KRAS下游衰老和增殖的关键调节因子的一个新的角色。Wt1的缺失导致小鼠原代细胞和人类肿瘤细胞以致癌的KRAS依赖的方式衰老。此外，在肺癌的小鼠模型中，WT1的表达在化疗耐药肿瘤细胞中特异性上调。这些发现揭示了WT1作为KRAS下游遗传网络的关键调节因子的一个意想不到的作用，并表明Wt1在化疗耐药中发挥了关键作用。在这个提案中，我们将结合分子、遗传和生化方法来阐明观察到的致癌KRAS和WT1之间相互作用的机制基础。初步数据表明，WT1的至少部分作用是由RNA的转录后调控介导的。因此，这项提案将使用最先进的方法来分析Wt1在剪接和蛋白质翻译中的作用。此外，我们还将确定WT1在调节KRAS驱动的肺癌化疗耐药性中的作用。

DESCRIPTION (provided by applicant): KRAS is one of the most frequently mutated human oncogenes. In some settings oncogenic KRAS can trigger cellular senescence, whereas in others expression leads to hyperproliferation. Given the importance of KRAS mutation in human cancer, elucidating the mechanisms regulating these two drastically distinct outcomes would help identify novel therapeutic approaches in RAS-driven cancers. We have identified a novel role for Wilms tumor-1 (WT1) as a critical regulator of senescence and proliferation downstream of oncogenic KRAS. Loss of Wt1 leads to senescence in mouse primary cells and human tumor cells in an oncogenic KRAS- dependent manner. In addition, WT1 expression is specifically upregulated in chemoresistant tumor cells in a mouse model of lung cancer. These findings reveal an unexpected role for WT1 as a key regulator of the genetic network downstream of KRAS and suggest a key role for Wt1 in chemoresistance. In this proposal, we will use a combination of molecular, genetic and biochemical approaches to elucidate the mechanistic basis for the observed interaction between oncogenic KRAS and WT1. Preliminary data suggests that at least part of the role of WT1 is mediated by post-transcriptional regulation of RNAs. Thus, this proposal will use state-of- the-art approaches to analyze the role of Wt1 on splicing and protein translation. In addition, we will determine the role of WT1 in regulating chemotherapy resistance in KRAS-driven lung tumors.