P53 AND ESTROGEN IN PCNA EXPRESSION OSTEOSARCOMA CELLS

PCNA 表达骨肉瘤细胞中的 P53 和雌激素

基本信息

批准号：
6376981
负责人：
GOKUL M. DAS
金额：
$ 21.55万
依托单位：
UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
依托单位国家：
美国
项目类别：
财政年份：
1999
资助国家：
美国
起止时间：
1999-08-01 至 2004-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/6376981
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

项目摘要

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.

本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改变的基因。 p53的失活被认为是骨肉瘤发展的重要一步。雌激素对于成骨细胞谱系的发育和功能很重要，并且雌激素刺激骨肉瘤细胞的增殖。然而，在存在和不存在功能性野生型p53的情况下雌激素作用的后果尚不清楚。尽管已知 p300/CBP 是 p53 介导和雌激素受体介导的基因调节的共激活因子，但 p53 和雌激素功能之间的关系仍不清楚。我们建议以骨肉瘤细胞中 PCNA 基因表达为模型，研究 p53 介导和雌激素介导的基因调控途径之间的功能相互关系及其与细胞增殖和细胞周期扰动的相关性。 PCNA 是细胞 DNA 复制和 DNA 修复机制的关键组成部分。骨肉瘤细胞中 PCNA 的表达受 p53 调节。我们的结果表明 PCNA 基因是雌激素诱导型的。此外，初步实验揭示了 p300/CBP 在介导 p53 对 PCNA 表达的调节中发挥着重要作用。基于早期的研究和初步数据，我们假设 p53 和雌激素信号通路在调节 PCNA 表达方面存在显着的串扰。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剂）调节 p53 介导的 PCNA 基因表达的机制。我们建议确定 p53-CBP 通路在雌激素诱导的 PCNA 表达和骨肉瘤细胞增殖中的作用。由于 PCNA 的相对量对于确定其与细胞周期中重要的其他蛋白质的相互作用非常重要，因此还假设 PCNA 表达受到 p53 和雌激素在细胞周期不同阶段的协调作用的差异调节。为了检验这一假设，我们将分析细胞周期中 p53 和雌激素对 PCNA 转录的调节。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。它还将为分析类固醇激素和 p53 之间的串扰来调节正常和异常细胞过程（例如肿瘤发生）中的基因表达提供范例。