NOVEL MUTATOR PHENOTYPES IMPORTANT IN HUMAN COLON CANCER

描述：该计划的目标是阐明 DNA错配修复（MMR）功能的丧失导致人类结肠的发生 微卫星不稳定性（MSI）的癌症，特别强调 了解作为散发性非家族性疾病出现的MSI结肠癌（在 最小的非经典HNPCC）。在此期间完成的大量工作的基础上， 在最初的供资期间，这一延续将侧重于了解 引起hMLH1启动子异常甲基化的机制，以及 将利用MSI结肠癌中存在的特定DNA修复缺陷， 开发针对这些肿瘤的新的诊断和治疗策略。 有五个具体目标。首先，为了确定hMLH1的甲基化是否是 由于顺式或反式的畸变，以及潜在的 细胞缺陷是显性或隐性的。第二，为了确定hMLH1 甲基化是结肠癌的起始或进展事件， 它与其它基因的甲基化串联或独立发生。三是 开发循环甲基化hMLH1 DNA的检测方法，作为以下疾病的诊断试验： 散发性MSI结肠癌的早期检测。第四，确定什么 ICR191的衍生物具有杀死MSI结肠癌的最佳选择性 无论是在细胞培养中还是在体内。第五，开发一种新的检测方法， 识别具有生殖系MMR突变的个体，通过增加基因组 它们培养的淋巴细胞的不稳定性， 等位基因，从而产生MMR缺陷和MNNG抗性。

DESCRIPTION: The goal of this program has been to elucidate mechanisms by which loss of DNA mismatch repair (MMR) function leads to genesis of human colon cancers with microsatellite instability (MSI), with particular emphasis on understanding MSI colon cancers that arise as sporadic non-familial disease (at a minimum, non-classical HNPCC). Based on extensive work accomplished during the initial funding period, this continuation will focus on understanding mechanisms that give rise to aberrant methylation of the hMLH1 promoter, and will exploit the specific DNA repair defect present in MSI colon cancers to develop new diagnostic and therapeutic strategies that target these tumors. There are 5 specific aims. First, to determine whether methylation of hMLH1 is due to an aberration that works in cis or in trans, and whether the underlying cellular defect is dominant or recessive. Second, to determine if the hMLH1 methylation is an initiation or progression event in colon cancer, and whether it occurs in tandem or independent of methylation of other genes. Third, to develop an assay for circulating methylated hMLH1 DNA as a diagnostic test for early detection of sporadic MSI colon cancer. Fourth, to determine what derivatives of ICR191 have optimal selectivity for killing MSI colon cancers both in cell culture and in vivo. Fifth, to develop a novel assay for recognizing individuals with germ line MMR mutations, by increasing genomic instability in their cultured lymphocytes that induces loss of the wild-type allele, thus generating MMR deficiency and MNNG resistence.