C-, N-, AND L-MYC EFFECTS ON HEMATOPOIETIC CELLS

C-、N- 和 L-MYC 对造血细胞的影响

• 批准号: 6628149
• 负责人: Edward Victor Prochownik
• 金额: $ 22.1万
• 依托单位: CHILDREN'S HOSP PITTSBURGH/UPMC HLTH SYS
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-04-01 至 2004-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6628149
• 关键词: DNA damage; antineoplastics; apoptosis; cell cycle proteins; cell growth regulation; cell line; cell proliferation; cell transformation; chimeric proteins; chromosome aberrations; cysteine endopeptidases; drug resistance; fibroblasts; flow cytometry; gene expression; hematopoietic stem cells; interleukin 3; molecular oncology; neoplasm /cancer genetics; oncogenes; oncoproteins; p53 gene /protein; phosphoprotein phosphatase; protein structure function; western blottings

Myc oncoproteins are involved in proliferation, differentiation, cell cycle progression, and apoptosis. The three major myc proteins, c-myc, N-myc, and L-myc, are also implicated in the pathogenesis of malignancies such as Burkitt's and AIDS-related lymphomas, breast cancer, neuroblastoma, and lung cancer. Little is known regarding the functional similarities of these proteins. We have shown that c-, N-, and L-myc differ in their ability to modulate c-myc-responsive promoters. Overexpression of c-myc is associated with increased sensitivity of hematopoietic cells to chemotherapeutic drugs whereas N-myc and L-myc produce resistance. In cells lacking p53, c-myc overexpression also produces genomic instability. In Specific Aim I, we will compare the abilities of c-, N-, and L-myc to restore normal levels of proliferation and transformation by c-myc-dependent oncogenes in c-myc-/- fibroblasts. In Specific Aim II, chimeric and mutant myc proteins will be used to map the domains responsible for imparting pharmacologic sensitivity or resistance to hematopoietic cells. In Specific Aim III, we will determine the role of cysteine proteases ("Caspases") in apoptosis mediated by c-, N-, and L-myc. Finally, in Specific Aim IV, we will again use mutant myc proteins to map the regions responsible for imparting genomic instability to hematopoietic cells lacking p53. We will ask if the overexpression of individual c-myc-regulated genes, is sufficient to produce genomic instability. Abnormalities of cyclins and their kinases will be examined. We will also ask if genes other than c-myc, which can induce unscheduled S-phase can substitute for c-myc in the induction of tetraploidy. Two different models for the induction of tetraploidy will also be tested. The above studies should provide new insights into how myc oncoproteins differ from one another with respect to the phenotypes they impart to hematopoietic cells.

Myc癌蛋白参与增殖、分化、细胞周期进程和凋亡。 三种主要的myc蛋白，c-myc、N-myc和L-myc，也涉及恶性肿瘤的发病机制，例如伯基特氏和AIDS相关的淋巴瘤、乳腺癌、神经母细胞瘤和肺癌。 关于这些蛋白质的功能相似性知之甚少。我们已经表明，c-，N-，和L-myc不同的能力，以调节c-myc响应启动子。 c-myc的过表达与造血细胞对化疗药物的敏感性增加有关，而N-myc和L-myc产生耐药性。 在缺乏p53的细胞中，c-myc过表达也会产生基因组不稳定性。 在特定目标I中，我们将比较c-、N-和L-myc在c-myc-/-成纤维细胞中通过c-myc依赖性癌基因恢复正常增殖和转化水平的能力。 在特定目标II中，嵌合和突变myc蛋白将用于绘制负责赋予造血细胞药理学敏感性或抗性的结构域。 在特定目标III中，我们将确定半胱氨酸蛋白酶（“半胱氨酸蛋白酶”）在c-，N-和L-myc介导的细胞凋亡中的作用。 最后，在《特定目的IV》中，我们将再次使用突变myc蛋白质来绘制负责赋予缺乏p53的造血细胞基因组不稳定性的区域。我们将询问单个c-myc调节基因的过表达是否足以产生基因组不稳定性。将检测细胞周期蛋白及其激酶的表达。 我们还将询问除了c-myc以外的可以诱导非预定S期的基因是否可以替代c-myc诱导四倍体。 还将测试用于诱导四倍体的两种不同模型。 上述研究应提供新的见解如何myc癌蛋白彼此不同的表型，他们赋予造血细胞。