Apoptotic Response to DNA Damage Initiated by PUMA

描述（由申请人提供）：细胞凋亡，或程序性细胞死亡，是保护细胞免受DNA损伤的基本生物学过程。参与调节细胞凋亡的基因缺陷在肿瘤中经常被发现。在哺乳动物细胞中，DNA损伤引起的细胞凋亡是由Bcl-2家族蛋白通过线粒体调控的。然而，DNA损伤引发细胞凋亡的机制仍有待进一步研究。我们最近的研究发现了一种名为PUMA的新型Bcl-2家族蛋白，它似乎在细胞死亡中起着重要作用。PUMA的诱导引发了人类癌细胞快速而深刻的凋亡反应。PUMA通过其他Bcl-2家族蛋白包括Bax、Bcl-2和Bcl-XL发挥作用。PUMA是p53的直接靶点，而p53在DNA损伤应答中起着核心作用。化疗药物，如DNA损伤剂阿霉素，也可以以p53依赖的方式诱导PUMA。此外，通过同源重组，结肠癌细胞中PUMA的缺失导致p53和阿霉素的凋亡反应明显降低。在此基础上，我们提出验证PUMA介导DNA损伤诱导的人癌细胞凋亡启动假说：目的1 .明确PUMA介导的人癌细胞凋亡启动机制；目标2。来确定

DESCRIPTION (provided by applicant): Apoptosis, or programmed cell death, is a fundamental biological process to protect cells from DNA damage. Defects in the genes involved in regulating apoptosis are frequently found in tumors. In mammalian cells, apoptosis induced by DNA damage is regulated through mitochondria by the Bcl-2 family of proteins. However, the mechanism by which DNA damage initiates apoptosis remains to be fully characterized. Our recent studies identified a novel Bcl-2 family protein called PUMA, which appears to play an important role in cell death. Induction of PUMA triggered a rapid and profound apoptotic response in human cancer cells. PUMA functions through other Bcl-2 family proteins including Bax, Bcl-2 and Bcl-XL. PUMA is a direct target of p53, which plays a central role in DNA damage response. PUMA can also be induced by chemotherapeutic drugs, such as the DNA damaging agent adriamycin, in a p53-dependent manner. Furthermore, deletion of PUMA in colon cancer cells by homologous recombination led to a markedly decreased apoptotic response to p53 and adriamycin. Based on these observations, we propose to test the hypothesis that PUMA mediates initiation of DNA damage-induced apoptosis in human cancer cells: Aim l. To define the mechanism of PUMA-mediated apoptosis initiation in human cancer cells; Aim 2. To determine if PUMA is activated through the p53-regulated DNA damage response pathway; Aim 3. To investigate if the apoptotic response to DNA damage is abrogated in PUMA-deficient cells.