(PQ1) The role of cell-to-cell variation in the penetrance of heritable mutant RAS hypodermal neoplasias

项目总结：我们的目标是回答这个问题：“什么分子 影响遗传癌症易感性个体疾病外显性的机制 吉恩？“我们计划从遗传学和细胞生物学的角度来回答这个问题。更确切地说， 我们计划确定哪些基因影响RAS驱动的肿瘤的外显性，然后 观察这些基因是如何改变基因表达和细胞分裂的刻板程序的 用定量光学显微镜直接观察基因表达和细胞分裂。 患有Noonan或Costello综合征的儿童出生时RAS基因突变最多 常见癌基因。这些人中的一些人，但不是所有人都会患上癌症。RAS驱动的癌症 是出了名的难以治疗。目前的抗HSP90临床试验显示出一些希望，但 毒品是有毒的。我们有证据表明，其他监护人可能是合适的目标 抑制以RAS为基础的癌症形成。我们有证据表明分子机制 影响RAS驱动的肿瘤外显率的是表观遗传的表达能力 更多或保持更多生物活性的蛋白质分子的单位基因。 在拟议的研究中，我们将研究具有RAS功能的同源线虫 导致不完全穿透性皮下肿瘤的等位基因。当这些动物继承了一个 他们唯一的RAS同源基因let-60的功能突变的获得，就像Noonan的孩子一样 综合症，他们中的一些人会发展成肿瘤。约90%的RAS癌基因携带蠕虫 将在发育过程中获得1-4个皮下肿瘤，以应对保守的癌症- 相关的EGF、Notch和WNT信号通路。在带有野生型RAS的蠕虫中，这些途径 通常会控制外阴的器官发生。肿瘤的最初表现 在开发过程中可靠地发生，一遍又一遍地发生 对于外阴发育来说。我们有一个系统，在这个系统中，我们确切地知道何时何地 这样我们就可以确切地看到细胞中发生了什么，这些细胞可能会变成肿瘤，也可能不会变成肿瘤。 我们将进行反向基因筛查，以确定影响肿瘤形成的基因。我们拭目以待 这些基因是如何改变一系列正常协调良好的基因表达事件的 通过测量发生在细胞中的基因表达来引起细胞增殖并改变细胞命运 活细胞。 我们特定的中心假设是，发生肿瘤的动物具有表观遗传学 伴侣表达的差异会导致翻译效率的提高，从而导致 更高的有效基因剂量的RAS获得的功能等位基因，反过来，导致 肿瘤的表现。我们在该方法中为这一假设提供了强有力的证据。

Project Summary: Our goal is to provide answers to the question: “What molecular mechanisms influence disease penetrance in individuals who inherit a cancer susceptibility gene?”. We plan to answer this question in terms of genetics and cell biology. More specifically, we plan to identify which genes influence the penetrance of RAS-driven neoplasia, and then observe how these genes alter the stereotyped program of gene expression and cell division by directly observing gene expression and cell division with quantitative light microscopy. Children with Noonan or Costello syndromes are born with mutations in RAS, the most common oncogene. Some, but not all of these individuals develop cancer. RAS-driven cancers are notoriously difficult to treat. Current anti-HSP90 clinical trials show some promise, but the drugs are toxic. We have evidence that other chaperones may be suitable targets for suppressing Ras-based cancer formation. We have evidence that the molecular mechanism that influences Ras-driven neoplasia penetrance is the epigenetically heritable ability to express more or maintain more biologically active molecules of protein per unit gene. In the proposed research, we will study isogenic C. elegans with a Ras gain of function allele that results in incompletely penetrant hypodermal neoplasia. When these animals inherit a gain of function mutation in their sole Ras homolog, let-60, just like children with Noonan syndrome, some of them will develop neoplasias. About 90% of Ras oncogene bearing worms will acquire 1-4 hypodermal neoplasias during development, in response to conserved, cancer- related EGF, Notch and WNT signaling pathways. In worms with wild-type Ras, these pathways would normally control organogenesis of the vulva. The initial manifestation of neoplasia happens reliably, at the same time during development, over and over – right when the signal for vulva development happens. We have a system wherein we know exactly where and when to look, so we can see exactly what happens in cells that may or may not become neoplastic. We will perform a reverse genetic screen to identify genes that affect neoplasia. We will watch how these genes change the series of normally well-coordinated gene expression events that cause cell proliferation and transform cell fate by measuring gene expression while it happens in living cells. Our specific central hypothesis is that animals that do develop neoplasias have epigenetic differences in chaperone expression that cause an increase in translation efficiency, resulting in a higher effective gene dosage of the Ras gain of function allele, and that in turn, results in the manifestation of neoplasia. We provide strong evidence for this hypothesis in the approach.