Molecular Pathogenesis of Ovarian Endometrioid Adenocarc

卵巢癌（OvCa）是女性癌症相关发病率和死亡率的主要原因，然而关于其发病机制仍有许多有待了解。 与其他癌症一样，OvCas被认为是通过多步骤过程产生的，其中体细胞突变和克隆选择的重复循环产生具有越来越积极的生长特性的变体后代。 在癌症中突变的基因通常编码在保守信号通路中起作用的蛋白质。 分子遗传学分析表明，OvCa的不同组织学亚型（例如，浆液性、透明细胞性、粘液性和类浆液性）可代表不同疾病实体，OvCa前体病变可能是亚型特异性的。 因此，更清楚地了解OvCa的发病机制可能更容易通过集中在不同的OvCa类型的细胞信号传导通路的缺陷的分子遗传学研究。 卵巢类囊腺癌（OEA）与子宫类囊腺癌有许多共同的分子遗传学特征，包括编码β-连环蛋白（β-cat）的CTNNB 1基因的频繁突变，β-连环蛋白是高度保守的Wnt信号通路的关键组分。先前的研究表明，虽然Wnt/β-cat/Tcf通路可能在相当大比例的OEAs中存在缺陷，但在OvCa的其他组织学亚型中很少发生改变。本申请描述了专注于定义Wnt途径缺陷有助于特定类型OvCa（即卵巢样腺癌）的发展和行为的分子机制的研究。 为此，我们提出了四个具体目标：1）完成对一大组原发性OEAs中已知调节Wnt/beta-cat/Tcf信号通路的蛋白质编码基因的全面突变分析; 2）表征在已知通路缺陷的OEAs中由beta-cat/Tcf信号通路转录激活的候选下游基因的表达; 3）检查子宫内膜异位症病变的光谱（推定的OEA前体），以确定β-cat/Tcf途径基因中的缺陷，并确定突变体β-cat的表达是否导致源自子宫内膜异位症的永生化细胞的恶性转化，和4）确定所选择的β-cat/Tcf-活化基因对于RK 3E细胞或与卵巢癌相关的人细胞（表达端粒酶的永生化卵巢表面上皮细胞，或源自子宫内膜异位的细胞系）中的突变型β-cat的肿瘤转化是否是必需的和/或足够的。

Ovarian carcinoma (OvCa) is a major cause of cancer- associated morbidity and mortality for women, yet much remains to be learned about its pathogenesis. Like other cancers, OvCas are thought to arise through a multi-step process in which repeated cycles of somatic mutation and clonal selection produce variant progeny with increasingly aggressive growth properties. The genes mutated in cancer frequently encode proteins that function in conserved signaling pathways. Molecular genetic analyses suggest that the different histologic subtypes of OvCa (e.g., serous, clear cell, mucinous, and endometrioid) may represent distinct disease entities and that OvCa precursor lesions may be subtype specific. Hence, a clearer understanding of OvCa pathogenesis might be more readily attained by focusing molecular genetic studies on distinct OvCa types for defects in cell signaling pathways. The ovarian endometrioid adenocarcinomas (OEAs) share a number of molecular genetic features with uterine endometrioid adenocarcinomas, including frequent mutations of the CTNNB1 gene which encodes beta-catenin (beta-cat), a critical component of the highly conserved Wnt signaling pathway. Previous studies suggest that although the Wnt/beta-cat/Tcf pathway may be defective in a substantial percentage of OEAs, it is only rarely altered in other histologic subtypes of OvCa. This application describes studies that are focused on defining the molecular mechanisms by which Wnt pathway defects contribute to the development and behavior of a specific type of OvCa, namely endometrioid adenocarcinomas. Toward this end, four specific aims are proposed: 1) To complete a comprehensive mutational analysis of genes encoding proteins known to regulate the Wnt/beta-cat/Tcf signaling pathway in a large group of primary OEAs; 2) To characterize expression of candidate downstream genes transcriptionally activated by the beta-cat/Tcf signaling pathway in OEAs with known pathway defects; 3) To examine a spectrum of endometriosis lesions (putative OEA precursors) for defects in beta-cat/Tcf pathway genes, and to determine whether expression of mutant beta-cat results in malignant transformation of immortalized cells derived from endometriosis, and 4) To determine if selected beta-cat/Tcf- activated genes are necessary and/or sufficient for neoplastic transformation by mutant beta-cat in RK3E cells or human cells with relevance to ovarian cancer (immortalized ovarian surface epithelial cells expressing telomerase, or cell lines derived from endometriosis).