The role of wild-type KRAS in the context of tumor profession and metastasis

 描述(由申请人提供)：KRAS是胰腺癌(&gt；90%)、结直肠癌(&gt；40%)和肺癌(&gt；16%)的主要致癌基因；这三种癌症导致23%的癌症发病率和43%的癌症。自然，一致的努力集中在开发针对致癌KRAS的治疗方法--抑制KRAS的表达、膜结合、效应信号通路等。然而，在过去的30年里，成功的程度有限。尽管这些过去的策略由于各种原因而失败，但一个共同点是它们既针对野生型(WT)，也针对致癌形式的KRAS。我们最近的出版物报道，在人类样本和小鼠模型中，致癌KRAS存在时WT-KRAS等位基因丢失增加与胰腺癌转移有关。我们还证明了WT-KRAS在胰腺癌细胞中的恢复表达在体外和体内都降低了癌细胞的侵袭力。这些发现挑战了对KRAS功能的经典观点，并促使我们假设在突变KRAS存在的情况下，WT-KRAS可能在转移中作为肿瘤抑制基因。到目前为止，很少有人关注WT-KRAS在癌症中的作用。为了验证我们的假设，在目标1中，我们将研究突变的胰腺癌细胞中wt-kras等位基因的丢失 KRAS会增加肿瘤负担和/或体内转移。在目标2中，我们将研究WT-Kras表达的恢复是否会在体内抑制胰腺肿瘤的进展和转移。目的建立Krasmt/wt和Krasmt/-型胰腺癌细胞的差异分子图谱，并研究这些差异表达基因的翻译价值。本文的创新之处包括：1)我们将采用体内多重荧光标记系统，对携带突变的Kras的胰腺癌细胞进行差异性标记，包括加或不加WT-Kras。我们将在小鼠体内追踪这些差异荧光标记的癌细胞，以视觉和定量的方式随着肿瘤的进展而转移。2)Aim 1和Aim 2的互补设计(评估WT-Kras在体内对肿瘤进展和转移的丢失或修复)将严格检验我们关于WT-Kras参与转移的假设。3)Aim 3中差异表达基因的鉴定不仅为Krasmt/wt和Krasmt/-胰腺癌细胞的表型差异提供了分子机制，也为下一代区分WT和突变KRAS信号的KRAS靶向治疗提供了潜在的预后标志物和新的基因靶点。尽管我们不能确定一种新的治疗方法区分WT和突变的KRAS的能力将是KRAS靶向治疗的灵丹妙药。然而，WT-KRAS在癌症转移中的潜在作用必须得到解决，并可能对未来的癌症研究和患者护理产生深远的影响。

 DESCRIPTION (provided by applicant): KRAS is a major oncogene for pancreatic (>90%), colorectal (>40%), and lung cancers (>16%); three cancer types that are responsible for 23% of cancer incidence and 43% cancer. Naturally, concerted efforts have focused on developing therapies against oncogenic KRAS- inhibition of KRAS expression, membrane association, effector signaling pathways, etc. However, success has been limited over the past 30 years. Although these past strategies have failed for diverse reasons, one commonality is that they target both the wild-type (WT) and oncogenic forms of KRAS. Our recent publication reported that increased loss of the WT-KRAS allele in the presence of oncogenic KRAS is associated with pancreatic cancer metastasis in both human samples and mouse modeling. We have also demonstrated that restoration of WT-KRAS expression in pancreatic cancer cells reduced cancer cell invasiveness in vitro and in vivo. These findings challenge the canonical view of KRAS functions and prompted us to hypothesize that the WT- KRAS may serve as a tumor-suppressor gene in metastasis in the presence of mutant KRAS. To-date, little attention has been bestowed on the function of WT-KRAS in the context of cancer. To test our hypothesis, in Aim 1, we will investigate if the loss of the WT-Kras allele in pancreatic cancer cells with mutant Kras would increase tumor burden and/or metastasis in vivo. In Aim 2, we will investigate if the restoration of WT-Kras expression will suppress pancreatic tumor progression and metastasis in vivo. Aim 3, we will generate differential molecular profiles between pancreatic cancer cells with Krasmt/wt and Krasmt/- genotypes and investigate the translational values of these differentially expression genes. The innovations here include: 1) We will employ in vivo multi-fluorescence labeling systems to differentially label pancreatic cancer cells that possess mutant Kras with or without WT-Kras. We will trace these differentially fluorescence-labeled cancer cells in mice as the tumors progress to metastasis, in both visual and quantitative manners. 2) The complementary designs of Aim 1 and Aim 2 (to evaluate the loss or restoration of WT-Kras on tumor progression and metastasis in vivo) will stringently test our hypothesis that the WT-Kras is involved in metastasis. 3) Finally, the identification of differentially expressed genes in Aim 3 wll not only provide the molecular mechanisms for the observed phenotypic differences between Krasmt/wt and Krasmt/- pancreatic cancer cells, but also potential prognostic markers and new gene targets for the next generation of KRAS target therapies that will distinguish between WT and mutant KRAS signaling. Although we cannot be certain that the ability for a new therapeutic to discriminate between WT and mutant KRAS will be the panacea for KRAS target therapies. Nevertheless, the potential role of WT-KRAS in cancer metastasis has to be addressed and may have profound impacts on future cancer research and patient care.