The Role of Fragile Sites in RET/PTC Rearrangement

脆弱位点在 RET/PTC 重排中的作用

• 批准号: 7048029
• 负责人: YUH-HWA WANG
• 金额: $ 28.42万
• 依托单位: UNIV OF MED/DENT NJ-R W JOHNSON MED SCH
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-13 至 2006-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7048029
• 关键词: DNA; genes; human; neoplasm /cancer; role

DESCRIPTION (provided by applicant): Chromosomal rearrangements are .common in many types of human cancer and play an important role in carcinogenesis. However, the mechanisms of rearrangement in cancer cells remain poorly understood, thyroid cancer represents an excellent model to study these mechanisms because of a common occurrence of chromosomal rearrangements involving the RET gene, called RETIPTC, and well-established association with DMA damage induced by ionizing radiation. However, radiation exposure accounts only for a small portion of all thyroid tumors, offering a chance to study the role of other factors in the generation of rearrangements. The proposed study aims to test directly if DMA fragility participates in the generation of chromosomal rearrangements in human cells. Our preliminary results showed that fragile site-inducing chemicals can induce breaks in the RET gene, and the rearrangement can be generated under fragile-site inducing conditions. To further investigate this, .we will first examine whether one or more chromosomal regions involved in RETIPTC in thyroid cells are part of fragile sites. Specifically, we will determine directly the physical relationship between the fragile sites and the RET, H4, and ELE1 genes. We will also find the frequency of DMA breaks in these regions after treatment with fragile site-inducing chemicals. Then, we will test whether fragile site expression can lead directly to the generation of RETIPTC rearrangements in human thyroid cells. We will test directly the induction of RET/PTC1 and RET/PTC3 rearrangements in human HTori-3 thyroid cells after chemical induction of fragile sites, and after inactivation of ATR or BRCA1, which has been shown to increase fragile site expression dramatically. Finally, we will determine whether two characteristic features of fragile sites, late DNA replication and secondary structure formation, exist in the regions involved in RETIPTC rearrangements, contributing to the DNA breakage in these areas. These studies will determine whether fragile sites participate in the generation of RETIPTC rearrangement in thyroid cells and allow to explore the mechanisms of fragility in these regions. This will extend our understanding of the molecular mechanisms of chromosomal rearrangements in cancer cells, and may eventually lead to the development of novel therapeutic or preventive measures for malignant tumors developing thro.ugh the mechanism of chromosomal rearrangements.

描述（由申请人提供）：染色体重排在许多类型的人类癌症中很常见，并在致癌作用中起重要作用。然而，癌细胞中重排的机制仍然知之甚少，甲状腺癌是研究这些机制的极好模型，因为涉及RET基因的染色体重排（称为RETIPTC）的常见发生，以及与电离辐射诱导的DMA损伤的良好关联。然而，辐射暴露仅占所有甲状腺肿瘤的一小部分，这为研究其他因素在重排产生中的作用提供了机会。这项拟议的研究旨在直接测试DMA脆性是否参与人类细胞中染色体重排的产生。我们的初步研究结果表明，脆性位点诱导化学品可以诱导断裂的RET基因，重排可以在脆性位点诱导条件下产生。为了进一步研究这一点，我们将首先检查甲状腺细胞中涉及RETPTC的一个或多个染色体区域是否是脆性位点的一部分。具体来说，我们将直接确定脆性位点与RET、H4和ELE 1基因之间的物理关系。我们还将发现用脆性位点诱导化学物质处理后这些区域中DMA断裂的频率。然后，我们将测试脆性位点表达是否可以直接导致人甲状腺细胞中RETPTC重排的产生。我们将直接测试在化学诱导脆性位点后以及ATR或BRCA 1失活后，人HTori-3甲状腺细胞中RET/PTC 1和RET/PTC 3重排的诱导，ATR或BRCA 1已显示显著增加脆性位点表达。最后，我们将确定是否脆性位点的两个特征，晚期DNA复制和二级结构的形成，存在于参与RETIPTC重排的区域，有助于在这些地区的DNA断裂。这些研究将确定脆性位点是否参与甲状腺细胞中RETPTC重排的产生，并允许探索这些区域的脆性机制。这将加深我们对癌细胞中染色体重排的分子机制的理解，并可能最终导致通过染色体重排机制发展的恶性肿瘤的新的治疗或预防措施的开发。