Arsenic Induced Miotic Arrest Associated Apoptosis

砷诱导的缩瞳抑制相关的细胞凋亡

• 批准号: 6687343
• 负责人: J CHRISTOPHER STATES
• 金额: $ 26.87万
• 依托单位: UNIVERSITY OF LOUISVILLE
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6687343
• 关键词: Chinese; aneuploidy; antisense nucleic acid; apoptosis; arsenic; basal cell carcinoma; cell growth regulation; chemical carcinogenesis; cyclins; flow cytometry; gene mutation; human genetic material tag; human tissue; p53 gene /protein; phosphorylation; squamous cell carcinoma; ultraviolet radiation

DESCRIPTION (provided by applicant): Arsenic is a natural contaminant of drinking water in many parts of the world, is a known human carcinogen and is #1 on the EPA list of hazardous chemicals. Cancers most often associated with chronic arsenism are squamous and basal cell carcinomas of the skin. How arsenic causes cancer is unknown. However, the National Research Council Report on Arsenic in Drinking Water concluded that the most likely mode of action is induction of numerical and structural chromosomal abnormalities. Arsenite, the carcinogenic form of arsenic found in drinking water, disrupts mitosis causing an anaphase delay and induces aneuploidy in normal diploid human fibroblasts and peripheral blood lymphocytes, and mitotic arrest associated apoptosis (MAAA) in p53 deficient human fibroblasts. The sensitivity of p53 deficient human cells to arsenite induced MAAA suggests that the mechanism of arsenite carcinogenesis is different than sunlight induced skin carcinogenesis in which p53 mutation is an early and common event. The hypothesis to be investigated is that p53 relieves the arsenite-induced anaphase block by activation of the G2 checkpoint response which inactivates cyclin B/cdc2 and derepresses the mitotic exit network and allow the cells to escape arsenite induced MAAA. It is the prevention of apoptosis in arsenic intoxicated cells that allows genetic instability (aneuploidy) after mitotic disruption. Identification of the cellular factors that interact with p53 or the p53 regulated genes to prevent mitotic arrest associated apoptosis and to allow cells to proceed through mitosis with a delay will provide valuable information regarding the mode of action of arsenite. The specific aims proposed are: 1.) Determine activation of the G2 checkpoint pathway in p53(+) and p53(-) cells arrested by arsenite in mitosis; 2.) Test by overexpression and targeted knockdown of G2 checkpoint proteins the role of G2 checkpoint activation in the escape from arsenite induced anaphase block; 3.) Test whether arsenic associated skin tumors are p53 wild type or mutant. The results of these studies will identify players mediating release from arsenite induced mitotic arrest, and will provide valuable information on the mechanism of arsenic induced carcinogenesis, clues to the usefulness of arsenite as a chemotherapeutic agent and valuable information on the mode of action of mitosis disrupting drugs in killing human cells.

描述（由申请人提供）：砷是世界许多地区饮用水的天然污染物，是一种已知的人类致癌物，并且在 EPA 危险化学品清单中名列第一。最常与慢性砷中毒相关的癌症是皮肤鳞状细胞癌和基底细胞癌。砷如何导致癌症尚不清楚。然而，国家研究委员会关于饮用水中砷的报告得出的结论是，最可能的作用方式是诱导染色体数量和结构异常。亚砷酸盐是饮用水中发现的砷的致癌形式，它会破坏有丝分裂，导致后期延迟，并诱导正常二倍体人成纤维细胞和外周血淋巴细胞的非整倍性，以及 p53 缺陷的人成纤维细胞中的有丝分裂停滞相关的细胞凋亡 (MAAA)。缺乏 p53 的人类细胞对亚砷酸盐诱导的 MAAA 的敏感性表明，亚砷酸盐致癌的机制不同于阳光诱导的皮肤癌，其中 p53 突变是一种早期且常见的事件。待研究的假设是p53通过激活G2检查点反应来缓解亚砷酸盐诱导的后期阻滞，G2检查点反应使细胞周期蛋白B/cdc2失活并去抑制有丝分裂出口网络并允许细胞逃避亚砷酸盐诱导的MAAA。砷中毒细胞中细胞凋亡的预防导致有丝分裂破坏后遗传不稳定（非整倍体）。鉴定与 p53 或 p53 调节基因相互作用以防止有丝分裂停滞相关的细胞凋亡并允许细胞延迟进行有丝分裂的细胞因子将提供有关亚砷酸盐作用模式的有价值的信息。提出的具体目标是： 1.) 确定在有丝分裂中被亚砷酸盐抑制的 p53(+) 和 p53(-) 细胞中 G2 检查点通路的激活； 2.) 通过 G2 检查点蛋白的过表达和靶向敲低来测试 G2 检查点激活在逃避亚砷酸盐诱导的后期阻滞中的作用； 3.) 测试砷相关皮肤肿瘤是p53野生型还是突变型。这些研究的结果将鉴定介导亚砷酸盐诱导的有丝分裂停滞释放的参与者，并将提供关于砷诱导致癌机制的有价值的信息、亚砷酸盐作为化疗剂的有用性的线索以及关于有丝分裂破坏的作用模式的有价值的信息杀死人体细胞的药物。