Searching for Genetic Basis for Metastasis of Differentiated Thyroid Cancer

 描述(申请人提供)：甲状腺癌是最常见的内分泌恶性肿瘤。大多数患者的病程都很缓慢，但由于担心远处转移等更具侵袭性的疾病，他们仍然接受了过于激进的标准治疗，具有讽刺意味的是，这种治疗对那些真正侵袭性的甲状腺癌并不真正有效。更好地了解远处转移的遗传基础对于 更准确的风险分层和更有效的治疗，但这一努力受到以下因素的限制 临床样本的缺乏。我们的研究小组之前已经建立了一种方法，利用睡美人(SB)转座子为基础的随机插入突变来研究癌症遗传学。使用这种方法，我们最近建立了一个晚期甲状腺癌的小鼠模型，该模型有较高的远处转移发生率。在这里提出的研究中，我们将使用这个模型来回答一个关于转移表型如何起源于原发DTC的基本问题，并检验这一假设，即转移特征是在原发肿瘤中的一个细胞亚群中形成的，这些新获得的突变为远处转移提供了选择优势(克隆选择模型)。这个问题将主要通过比较原发肿瘤和转移灶中的Sb插入位置来解决。第一个目的是在原发灶中建立唯一的克隆SB插入位点作为其分子标志后，分离原发灶的克隆起源，然后通过研究其表达谱来确定该克隆是否获得了任何有利于转移的新表型。第二个目的是在人群水平上分析原发癌和转移性癌中的SB插入位点，以确定是否存在任何转移性病变的共同插入位点(MET-CIS)，这表明转移病变中新获得的突变和表型，或者在有显著转移的原发肿瘤中富含的CI(PREMET-CIS)，这将提示原发肿瘤发生变化时易发生转移的基因/途径。同样在第三个目标中，我们将试图通过在晚期人类甲状腺癌样本中寻找与转移相关的基因来验证目标#2中发现的与转移相关的基因，并在体外和体内测试它们的致癌和转移特性。这些实验的结果将成为未来转化为转移性甲状腺癌分子标记和治疗靶点的研究的基础。

 DESCRIPTION (provided by applicant): Thyroid cancer is the most common endocrine malignancy. Most of the patients have an indolent course, but for fear of more aggressive diseases such as distant metastasis, have nonetheless been treated with over-aggressive standard treatment, which ironically is not really effective towards those truly aggressive forms of thyroid cancer. Better understanding of the genetic basis of distant metastasis is essential for more accurate risk stratification and more effective treatment, but this effort has been limited by the lack of clinical samples. Our research group has previously established a method to use Sleeping Beauty (SB) transposon- based random insertional mutagenesis for study of cancer genetics. Using this method, we have recently created a mouse model of advanced thyroid cancer with a high incidence for distant metastasis. In the research proposed here, we will use this model to answer a fundamental question regarding how metastatic phenotypes originate from the primary DTC and test the hypothesis that the metastatic traits take shape in a subpopulation of cells in the primary tumor from newly acquired mutations which offer selection advantage for distant metastasis (clonal selection model). This question will mainly be addressed by comparing the SB insertion sites in the primary tumors and the metastatic lesions. The first aim attempts to isolate the clonal origin of a metastatic lesion in the primary tumor, after establishing unique clonal SB insertion sites in the metastatic lesion as its molecular signature, and then determine if this clone has acquired any novel phenotypes that favor metastasis by studying its expression profile. The second aim will analyze the SB insertion sites at the population level in both primary and metastatic DTC to decide if there are any common insertion sites (CIS) specific for metastatic lesion (met-CIS), which would indicate newly acquired mutations and phenotypes in the metastatic lesions, or CISs enriched in primary tumors with significant metastasis (premet-CIS), which would suggest genes/pathways predisposing to metastasis when altered in the primary tumor. Also in third aim, we will try to validate the genes associated with metastasis found in the aim #2 by looking for their alterations in advanced human thyroid cancer samples, and test their oncogenic and metastatic properties in vitro and in vivo. The results of these experiments will be the basis of the future translationa research to develop molecular markers and treatment targets for metastatic thyroid cancer.