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: 6350303
• 负责人: Edward Victor Prochownik
• 金额: $ 21.05万
• 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/6350303
• 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、细胞周期进程和细胞凋亡。 三种主要的 myc 蛋白，c-myc、N-myc 和 L-myc，也与伯基特氏淋巴瘤和艾滋病相关淋巴瘤、乳腺癌、神经母细胞瘤和肺癌等恶性肿瘤的发病机制有关。 关于这些蛋白质的功能相似性知之甚少。我们已经证明 c-、N- 和 L-myc 在调节 c-myc 响应启动子的能力上有所不同。 c-myc 的过度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 会产生耐药性。 在缺乏 p53 的细胞中，c-myc 过度表达也会产生基因组不稳定。 在特定目标 I 中，我们将比较 c-、N- 和 L-myc 通过 c-myc-/- 成纤维细胞中 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，嵌合和突变型 myc 蛋白将用于绘制负责赋予造血细胞药理学敏感性或耐药性的结构域。 在特定目标 III 中，我们将确定半胱氨酸蛋白酶（“Caspase”）在 c-、N- 和 L-myc 介导的细胞凋亡中的作用。 最后，在特定目标 IV 中，我们将再次使用突变型 myc 蛋白来绘制负责向缺乏 p53 的造血细胞赋予基因组不稳定性的区域。我们将询问单个 c-myc 调节基因的过度表达是否足以产生基因组不稳定。将检查细胞周期蛋白及其激酶的异常情况。 我们还将询问除了c-myc之外的能够诱导非预定S期的基因是否可以替代c-myc来诱导四倍体。 还将测试用于诱导四倍体的两种不同模型。 上述研究应该为 myc 癌蛋白在赋予造血细胞的表型方面如何彼此不同提供新的见解。