Searching for Genetic Basis for Metastasis of Differentiated Thyroid Cancer

 描述（由申请人提供）：甲状腺癌是最常见的内分泌恶性肿瘤。大多数患者都有一个惰性的过程，但由于担心更积极的疾病，如远处转移，仍然接受了过度积极的标准治疗，具有讽刺意味的是，这对那些真正具有侵略性的甲状腺癌形式并不真正有效。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，但这一努力受到限制， 缺乏临床样本。本课题组建立了一种基于睡美人转座子的随机插入突变方法，用于肿瘤遗传学研究。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，具有很高的远处转移率。在这里提出的研究中，我们将使用这个模型来回答一个基本问题，即转移表型如何起源于原发性DTC，并测试转移性状在原发性肿瘤中的细胞亚群中形成的假设，这些细胞亚群来自新获得的突变，这些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性肿瘤和转移性病变中的SB插入部位来解决。第一个目标是在转移性病变中建立独特的克隆SB插入位点作为其分子标记后，尝试分离原发性肿瘤中转移性病变的克隆起源，然后通过研究其表达谱来确定该克隆是否获得了有利于转移的任何新表型。第二个目的是在群体水平上分析原发性和转移性DTC中的SB插入位点，以确定是否存在任何转移性病变特异性的共同插入位点（CIS）（met-CIS），这将指示转移性病变中新获得的突变和表型，或在具有显著转移的原发性肿瘤中富集的CIS（premet-CIS），这将表明当在原发性肿瘤中改变时易发生转移的基因/途径。同样在第三个目标中，我们将尝试通过在晚期人类甲状腺癌样本中寻找与转移相关的基因的改变来验证目标2中发现的与转移相关的基因，并在体外和体内测试其致癌和转移特性。这些实验的结果将是未来开发转移性甲状腺癌分子标记物和治疗靶点的基础。

 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.