Molecular Biology of Lung Cancer among Puerto Ricans

摘要：个体癌症潜在突变的差异可以极大地影响最佳治疗选择，并且越来越清楚的是，不同种族的人群在哪些突变驱动他们的肺癌方面存在显着差异。肺癌是波多黎各（PR）男性的主要癌症杀手，也是PR女性的第二大杀手。尽管如此，关于PR中驱动肺癌的分子机制知之甚少。例如，最近的研究表明，拉丁美洲人群中的表皮生长因子受体（EGFR）突变率明显高于白人和非洲裔美国人。该信息很重要，因为EGFR突变在临床上是可靶向的。本申请提出建立约100例PR肺癌患者的肺癌分子数据库。本文所述的工作将具体解决PR肺癌患者在美国大陆白色人群中最常突变的基因中具有不同突变模式的假设。实验将评估KF 1AS、TP 53、EGFR、BF 1AF、CDKN 1C和RBI的改变。如果这一假设得到证实，它可能会极大地影响PR肺癌患者的基因检测和治疗建议，因为这些突变中的许多都可以在临床上靶向。也许最重要的是，这些努力将创建一个重要的数据和组织库，这将有利于未来对PR男性主要癌症杀手的研究。该提案还将探索视网膜母细胞瘤（RB 1）通路在肺癌中的作用。RBI是第一个被发现的肿瘤抑制基因，但它作为肿瘤抑制基因的效力仍然只有部分解释。在令人兴奋的新实验中，我们发现了pRb（RB 1基因的蛋白产物）在调节细胞间相互作用中的作用。这是一个新的作用，因为pRb主要是已知的细胞周期调节剂。发现pRb是调节钙粘蛋白表达所必需的，钙粘蛋白是参与细胞粘附的粘附连接结构的组分。由于pRb缺失导致的钙粘蛋白表达异常导致细胞粘附连接中断和粘附特性受损。比较Rb+/+和Rb-/-细胞的表达微阵列显示，pRb影响广泛的细胞粘附相关基因的转录，包括各种整合素和钙粘蛋白。重要的是，对实验室可用的基因表达数据集的检查表明，这些pRb调节的细胞粘附基因的子集的表达水平与肺腺癌（AC）的总生存率密切相关。这表明异常的细胞粘附相关基因表达，可能是由于pRb失活（直接或作为CDKN 2A沉默的结果），可能与AC的分子病因学有关。这项申请有三个具体目标。第一个目标将集中于使用肿瘤来源的DNA创建对应于约100个PR NSCLC（非小细胞肺癌）患者的分子数据库。首先，我们将鉴定非小细胞肺癌中常见突变基因中存在的突变（包括KRAS、TP 53、EFGR、RBI、B-RAF和ALK融合体^。此外，我们将通过测量CDKN 2A启动子甲基化和CDKN 2A基因重排来监测RBI通路的失调。第二个目标将利用来自相同的~100名患者的肿瘤来源的mRNA进行基于微阵列的基因表达分析。我们将使用聚类方法来绘制突变模式（在目标1中观察到）与表达谱（在目标2中观察到）之间的相关性。我们假设CDKN 2A/RB 1途径的遗传改变可能与Rb调节的细胞粘附基因的失调密切相关。最后，第三个目标将侧重于基本的|pRb如何在细胞和分子水平影响细胞与细胞粘附的生物学。具体而言，这一目标是集中在表征的分子机制，pRb促进细胞粘附从其核的位置。我们将在目标3中检验的假设是pRb通过以涉及小Rho GTdR ae 1的方式调节细胞膜处粘附连接的组装和稳定来影响细胞粘附。

Abstract: Differences in the mutations underlying an individual's cancer can dramatically affect the best treatment choice and it is becoming clear that different ethnic populations differ significantly in which mutations drive their lung cancers. Lung cancer is the leading cancer killer among Puerto Rican (PR) men and second killer among PR women. Despite this fact, little is known regarding the molecular mechanisms driving lung cancer among PRs. For example, recent work has shown that the rate of epidermal growth factor receptor (EGFR) mutations in Latin American populations is significantly higher than Whites and African Americans^. This information is important as EGFR mutations are targetable in the clinic. This application proposes to establish a lung cancer molecular database on ~100 PR lung cancer patients. The work described herein will specifically address the hypothesis that PR lung cancer patients have a different pattern of mutations in genes that are most commonly mutated in the White, mainland US population. Experiments will assess alterations in KFiAS, TP53, EGFR, BFiAF, CDKN1C and RBI. If this hypothesis is verified, it could dramatically affect genetic testing and treatment recommendations for PR lung cancer patients since many of these mutations can be targeted clinically¿. Perhaps most importantly, these efforts will create a significant data and tissue repository that will benefit future research on the leading cancer killer of PR men. This proposal will also probe the role of the retinoblastoma {RB1) pathway in lung cancer. RBI was the first tumor suppressor gene to be discovered, and yet its potency as a tumor suppressor remains only partially explained. In exciting new experiments, we have uncovered a role for pRb (the protein product of the RB1 gene) in the regulation of cell-to-cell interactions^. This is a novel role since pRb is predominantly known as a cell-cycle regulator. pRb is found to be required for the regulated expression of cadherins, which are components of the adherens junction structures involved in cellular adhesion. Abnormal cadherin expression due to pRb loss resulted in cells with disrupted adherens junctions and impaired adhesive properties. Expression microarrays comparing Rb+/+ and Rb-/- cells show that pRb impacts the transcription of a wide repertoire of cell adhesion-related genes, including various integrins and cadherins. Importantly, the examination of publically available gene expression datasets demonstrates that the expression levels of a subset of these pRb-regulated cell adhesion genes strongly correlates with overall survival in lung adenocarcinoma (AC). This suggests that aberrant cell adhesion-related gene expression, possibly due to pRb inactivation (directly or as a result of CDKN2A silencing), could be related to the molecular etiology of AC. This application has three specific aims. The first aim will focus on creating a molecular database corresponding to ~100 PR NSCLC (non-small-cell lung cancer) patients using tumor-derived DNA. First, we will identify the mutations present in genes commonly mutated genes in NSCLC (including KRAS, TP53, EFGR, RBI, B-RAF- and ALK fusions^. In addition, we will monitor deregulation of the RBI pathway by measuring CDKN2A promoter methylation and CDKN2A gene rearrangements. The second aim will utilize tumor-derived mRNA from the same ~100 patieints for microarray-based gene expression analysis. We will use clustering approaches to draw correlations between the mutation patterns (observed in Aim 1) with expression profiles (observed in Aim 2). We hypothesize that genetic alterations of the CDKN2A/RB1 pathway may be found to correlate well with the deregulation of Rb-regulated cell adhesion genes. Finally, the third aim will focus on the basic | biology of how pRb affects cell-to-cell adhesion at the cellular and molecular levels. Specifically, this aim is focused on the characterization of the molecular mechanisms by which pRb promotes cell adhesion from its nuclear position. The hypothesis that we will test in Aim 3 is that pRb impinges on cell adhesion by regulating the assembly and stabilization of adherens junctions at the cell membrane in a manner that involves the small Rho GTPase Rae 1.