Functional and Clinical Analysis of Rak in Breast Cancer Suppression

Rak抑制乳腺癌的功能和临床分析

• 批准号: 7210323
• 负责人: Shiaw-Yih Lin
• 金额: $ 26.33万
• 依托单位: UNIVERSITY OF TX MD ANDERSON CAN CTR
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-12-05 至 2011-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7210323
• 关键词: 6q21; Cancer cell line; Cell Cycle Arrest; Cell Cycle Checkpoint; Cell Line; Cell Nucleus; Cells; Chromosome abnormality; Chromosomes; Clinical; Core Facility; DNA; DNA Damage; DNA damage checkpoint; Data; Development; Epigenetic Process; Epithelial Cells; Genome Stability; Genomic Instability; Genomics; Genotoxic Stress; Human; Knock-out; Loss of Heterozygosity; Maintenance; Malignant Neoplasms; Mammary Neoplasms; Mammary gland; Mediating; Mutation; Nuclear; Nucleic Acids; Numbers; Pathologic; Patients; Play; Polymerase Chain Reaction; Process; Prognostic Marker; Proliferating; Protein Analysis; Proteins; Radiation; Receptor Protein-Tyrosine Kinases; Research Personnel; Role; Sampling; Signal Transduction; Spectral Karyotyping; Telomerase; Testing; Therapeutic; Time; Tissues; Tumor Bank; Tumor Suppressor Genes; base; cell immortalization; chromatin immunoprecipitation; comparative genomic hybridization; improved; in vivo; intracellular protein transport; irradiation; malignant breast neoplasm; metaplastic cell transformation; mouse model; novel; prevent; programs; promoter; protein localization location; response; small hairpin RNA; therapeutic target; transmission process; tumor; tumorigenesis

DESCRIPTION (provided by applicant): Loss of cell cycle checkpoint control and acquisition of the ability to proliferate indefinitely constitute 2 of the fundamental changes required for the development of cancer. Rak, a non-receptor tyrosine kinase identified through our enhanced retroviral mutation screen as a repressor of hTERT function, has been implicated in cellular immortalization. Our preliminary data indicates that Rak has additional functions in the transmission of DNA damage signals and is required for intact DNA damage checkpoints. Moreover, Rak is located on chromosome 6q21-23, a region that undergoes loss of heterozygosity in 30% of breast cancer cases. Rak expression is also significantly reduced in breast cancer tissues and cancer cell lines as analyzed by DNA arrays, real-time PCR, and protein analysis. Thus, we hypothesize that Rak may function as a tumor suppressor gene in breast cancer through dual functions: repressing cellular immortalization and maintaining genomic stability. This hypothesis will be tested in the following steps. (1) We will determine the role of Rak in preventing cellular immortalization by using normal human mammary epithelial cells that conditionally express small hairpin RNA against Rak, and we will investigate the mechanisms mediating Rak's function on hTERT expression. (2) We will use Rak-depleted cells to study the role of Rak in the response to genotoxic stress, maintenance of genomic integrity, and cellular transformation; for these studies, we will assess genomic instability by using comparative genomic hybridization (CGH) and spectral karyotyping (SKY) to visualize chromosomal aberrations; we will study how Rak may participate directly in transmitting DNA damage signals; and we will use a knockout mouse model to assess Rak's function in vivo in maintaining genomic integrity and suppressing tumor formation. (3) We will identify and characterize aberrations in Rak in samples from patients with breast cancer to determine if Rak serves as a prognostic marker or a therapeutic target in cancer. As a corollary, analyzing the function of Rak and its aberrations in patients with cancer will contribute to an improved understanding of the key pathologic alterations in cancer initiation and progression and to the development of novel, effective therapeutic approaches for cancer. Relevance: Rak plays a dual role in preventing cell immortalization and maintaining genomic stability. Our studies have identified Rak as a potentially important tumor suppressor gene in breast cancer. An analysis of the function of Rak and its network of interacting proteins will clarify the key pathologic alterations in cancer initiation and progression and eventually will aid in the development of novel, effective therapeutic approaches for breast cancer.

描述(由申请人提供)：失去细胞周期检查点控制和获得无限期增殖的能力构成了癌症发展所需的基本变化中的2个。RAK是一种非受体酪氨酸激酶，通过我们的增强型逆转录病毒突变筛查发现，它是hTERT功能的抑制因子，与细胞永生化有关。我们的初步数据表明，RAK在DNA损伤信号的传递中具有额外的功能，并且是完整的DNA损伤检查点所必需的。此外，RAK基因位于染色体6q21-23上，该区域在30%的乳腺癌病例中发生杂合性缺失。通过DNA阵列、实时荧光定量聚合酶链式反应和蛋白质分析，RAK在乳腺癌组织和癌细胞系中的表达也显著降低。因此，我们推测RAK可能通过抑制细胞永生化和维持基因组稳定性的双重功能在乳腺癌中发挥抑癌基因的作用。这一假设将在以下步骤中得到检验。(1)我们将通过有条件地表达抗RAK的小发夹状RNA的正常人乳腺上皮细胞来确定RAK在防止细胞永生化中的作用，并探讨RAK对hTERT表达的调节机制。(2)我们将使用RAK缺失的细胞来研究RAK在应对遗传毒性应激、维持基因组完整性和细胞转化中的作用；在这些研究中，我们将通过比较基因组杂交(CGH)和光谱核型分析(SKY)来评估基因组的不稳定性；我们将研究RAK如何直接参与传递DNA损伤信号；以及我们将使用敲除小鼠模型来评估RAK在体内维持基因组完整性和抑制肿瘤形成中的功能。(3)我们将从乳腺癌患者的样本中鉴定和鉴定RAK基因的异常，以确定RAK基因是否可以作为癌症的预后标志或治疗靶点。因此，分析RAK的功能及其在癌症患者中的异常将有助于更好地理解癌症发生和发展中的关键病理变化，并有助于开发新的、有效的癌症治疗方法。相关性：RAK在防止细胞永生化和维持基因组稳定性方面具有双重作用。我们的研究已经确定RAK基因是乳腺癌中一个潜在的重要抑癌基因。对RAK及其相互作用蛋白网络的功能分析将阐明癌症发生和发展中的关键病理变化，最终将有助于开发新的、有效的乳腺癌治疗方法。