A novel mutation in the T8 microsatellite of 3-UTR CDK2-AP1 gene in MSI CRC

描述（申请人提供）：。本应用程序的目的是确定最近发现的在微卫星不稳定（MSI）结直肠癌（CRC）中细胞周期蛋白依赖性激酶-2-相关蛋白1 （CDK2-AP1）基因3'- utr poly(T)8中的del T突变的频率和作用。目前的文献认为有两种途径导致侵袭性结直肠癌。微卫星稳定（MSS）途径是最常见的途径，在大约80%的CRC病例中可见，其中未观察到微卫星序列改变。另一种途径是MSI途径，在剩余的20%的CRC病例中可以解释，其特征是帧移位突变和微卫星DNA的碱基对替换。CDK2-AP1在RC病因学中是一种已知的生长抑制因子。我们之前报道过CDK2-AP1在人MS - RC细胞系中的表达显著降低（Yuan et al., 2003），其诱导导致细胞增殖减少，细胞凋亡增加（Kent et al., 2004）。最近，我们在25%的MSI CRC细胞系（12个中的3个）中检测到CDK2-AP1基因3'-UTR poly (T)8中的del T与DK2-AP1表达降低有关（Yuan et al., 2005）。在Ruggiero同时进行的一项研究中，他描述了人类MSI CRC中CEACAM1基因3'-UTR区域的类似多聚T(8)改变，这加强了我们的项目。基于我们之前发表的研究结果，我们假设：1)CDK2-AP1基因3'-UTR多聚(T)8中的del T是MSI CRC中常见的改变，2)观察到del T是体细胞改变，与CDK2-AP1表达减少有关。在这个拟议的项目中，我们将通过完成以下具体目标来验证我们的假设：具体目标1:a)我们将确定人类MSI CRC中CDK2-AP1基因3'-UTR的poly (T)8中del T的频率；b)为了进一步确定这种改变是体细胞突变还是种系突变，我们将把鉴定出的阳性CRC样本与正常组织对进行比较。特异性目的2：我们将描述这种del T改变在人MSI CRC中CDK2-AP1表达降低中的作用。完成我们提出的特异性目标将促进我们对MMR缺陷CRC中CDK2-AP1表达降低的机制的了解。在本初步研究完成后，将进一步确定大量CRC患者的del T改变，以确定高危人群。

DESCRIPTION (provided by applicant): . The objective of this application is to define the frequency and role of a recently discovered del T alternation in poly(T)8 in the 3'-UTR of the Cyclin Dependent Kinase-2- Associated Protein-1 (CDK2-AP1) gene in Microsatellite unstable (MSI) colorectal cancer (CRC). Current literature recognizes two pathways lead to invasive CRC. Microsatellite stable (MSS) pathway is the most common pathway, seen in approximately 80% of CRC cases, in which no microsatellite sequence alterations were observed. The other pathway is MSI pathway, explained in the remaining 20% of CRC cases, characterized by frame shift mutations and base-pair substitutions of the microsatellite DNA. CDK2-AP1 is a known growth suppressor in the etiology of RC. We previously reported that the CDK2-AP1 expression has been significantly decreased in human MS RC cell lines (Yuan et al., 2003) and its induction resulted in decreased cell proliferation and increased apoptosis (Kent et al., 2004). Recently, we detected a frequent, novel single alteration, del T in poly (T)8 of the 3'-UTR of the CDK2-AP1 gene in 25% of MSI CRC cell lines (3 of 12), is associated with decreased DK2-AP1 expression (Yuan et al., 2005). In a concurrent study by Ruggiero, described a similar poly T(8) alteration in 3'-UTR region of the CEACAM1 gene in human MSI CRC, strengthens our project. Based on our previously published findings, we hypothesize: 1). del T in a poly (T)8 of the 3'-UTR of the CDK2-AP1 gene is a frequent alteration in MSI CRC, 2) observed del T is a somatic alteration, associated with decreased expression of CDK2-AP1. In this proposed project, we will test our hypothesis by completion of he following Specific Aims: Specific Aim 1: a) We will determine the frequency of the del T in a poly (T)8 of he 3'-UTR of the CDK2-AP1 gene in human MSI CRC; b) To further determine this alteration is a somatic or a germline mutation, we will compare the identified positive CRC sample with normal tissue pairs. Specific Aim 2: We will characterize the role of this del T alteration in decreased expression of CDK2-AP1 in human MSI CRC. Completion of our proposed Specific Aims will advance our knowledge about the mechanism of decreased CDK2-AP1 expression in MMR deficient CRC. At the completion of this proposed pilot study, will urther determine del T alteration in a large number of CRC patients to identify high risk population.