P53 AND ESTROGEN IN PCNA EXPRESSION OSTEOSARCOMA CELLS

PCNA 表达骨肉瘤细胞中的 P53 和雌激素

• 批准号: 2903068
• 负责人: GOKUL M. DAS
• 金额: $ 18.65万
• 依托单位: CANCER THERAPY AND RESEARCH CENTER
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-08-01 至 2000-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2903068
• 关键词: antisense nucleic acid; cell growth regulation; cell proliferation; estrogen receptors; estrogens; gene expression; gene induction /repression; genetic promoter element; genetic transcription; hormone regulation /control mechanism; neoplastic cell; osteosarcoma; p53 gene /protein; tissue /cell culture; transfection; tumor antigens

The objective of the proposed study is to analyze the cross-talk between the tumor suppressor protein p53 and estrogen signaling pathways in human osteosarcoma cells. The p53 gene is the most frequently altered gene in various human cancers. Inactivation of p53 is considered to be an important step in the development of osteosarcomas. Estrogens are important in the development and functioning of the osteoblast lineage and estrogens stimulate proliferation of osteosarcoma cells. However, consequence of estrogen action in the presence and in the absence of functional wild type p53 is not clear. Although it is known that p300/CBP is a coactivator for both p53-mediated and estrogen receptor-mediated gene regulation, the relationship between p53 and estrogen functions remains unknown. We propose to investigate the functional interrelationship between pathways of p53-mediated and estrogen-mediated gene regulation and its relevance to cell proliferation and perturbation of cell cycle, using PCNA gene expression in osteosarcoma cells as a model. PCNA is a critical component of the cellular DNA replication and DNA repair machineries. PCNA expression in osteosarcoma cells is regulated by p53. Our results show that the PCNA gene is estrogen-inducible. Furthermore, preliminary experiments have revealed a major role for p300/CBP in mediating regulation of PCNA expression by p53. Based on earlier studies and preliminary data, we hypothesize that there is significant cross-talk between p53 and estrogen signaling pathways in regulating PCNA expression. To test this hypothesis, we will analyze the mechanisms by which p300/CBP, a coactivator for both p53 and estrogen receptor, regulates p53-mediated PCNA gene expression. We propose to determine the role of p53-CBP pathway in estrogen-induced PCNA expression and proliferation of osteosarcoma cells. Since the relative amount of PCNA is important in specifying its interaction with other proteins important for the cell cycle, it is also hypothesized that PCNA expression is differentially regulated by coordinated action of p53 and estrogen in different stages of the cell cycle. To test this hypothesis, PCNA transcriptional regulation by p53 and estrogen during the cell cycle will be analyzed. The proposed study will provide important information on the role of estrogen in proliferation and cell cycle checkpoint function in the presence and in the absence of functional p53. It will also provide a paradigm for analyzing cross-talk between steroid hormones and p53 in regulating gene expression in both normal and abnormal cellular processes such as oncogenesis.

拟议的研究的目的是分析人骨肉瘤细胞中肿瘤抑制蛋白p53和雌激素信号通路之间的串扰。 p53基因是各种人类癌症中最常见的基因。 p53的灭活被认为是骨肉瘤发展的重要步骤。 雌激素在成骨细胞谱系和雌激素的发育和功能中很重要，刺激骨肉瘤细胞的增殖。 然而，在存在的情况下，在没有功能性野生型p53的情况下，雌激素作用的结果尚不清楚。 尽管众所周知，p300/cbp是p53介导的和雌激素受体介导的基因调控的共激活因子，但p53和雌激素功能之间的关系仍然未知。 我们建议使用骨肉瘤细胞中的PCNA基因表达来研究p53介导的和雌激素介导的基因调节和与细胞增殖和细胞周期扰动的相关性之间的功能相互关系。 PCNA是细胞DNA复制和DNA修复机器的关键组成部分。 骨肉瘤细胞中的PCNA表达受p53调节。 我们的结果表明，PCNA基因是雌激素诱导的。 此外，初步实验揭示了p300/cbp在p53调节PCNA表达中的主要作用。基于较早的研究和初步数据，我们假设p53和雌激素信号通路之间在调节PCNA表达时存在明显的串扰。 为了检验这一假设，我们将分析p300/cbp（p53和雌激素受体的共激活因子）调节p53介导的PCNA基因表达的机制。 我们建议确定p53-CBP途径在雌激素诱导的PCNA表达和骨肉瘤细胞增殖中的作用。 由于PCNA的相对量对于指定其与细胞周期重要的其他蛋白质相互作用很重要，因此也可以假设，PCNA表达受到细胞周期不同阶段的p53和雌激素的协调作用的差异调节。为了检验该假设，将分析PCNA在细胞周期中对P53和雌激素的转录调节。 拟议的研究将提供有关雌激素在存在和不存在功能性p53的情况下在增殖和细胞周期检查点功能中的作用的重要信息。 它还将提供一个范式，用于分析类固醇激素和p53之间在正常和异常细胞过程（例如肿瘤发生）中调节基因表达的串扰。