p53 Acetylation as a Mechanism in Chemoprevention by Aspirin

p53 乙酰化作为阿司匹林化学预防的机制

基本信息

批准号：
7751188
负责人：
Jayarama B Gunaje
金额：
$ 7.43万
依托单位：
TEXAS TECH UNIVERSITY HEALTH SCIS CENTER
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-07-17 至 2011-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7751188
关键词：
Abnormal DNA Repair Acetylation Affect Aflatoxins Agreement Alkylating Agents Antineoplastic Agents Apoptosis Apoptosis Regulator Aspirin Attention Binding Biological Assay Breast Breast Cancer Cell Camptothecin Cancer cell line Cardiovascular Diseases Cell Cycle Cell Cycle Arrest Cell Cycle Progression Cell Death Cell Survival Cells Chemoprevention Chemopreventive Agent Chemosensitization Cisplatin Clinical Clinical Research Colon Carcinoma DNA Damage Degenerative polyarthritis Development Dose Down-Regulation Doxorubicin Drug usage Electrophoretic Mobility Shift Assay Epidemiology Epithelial Epithelial Cells Exposure to Flow Cytometry Fluorouracil Food Gene Expression Gene Targeting Genes Genetic Transcription Headache Hepatocyte Heterocyclic Amines Human Hydrocarbons In Vitro Injury Intake Kinetics Leucovorin Literature Lung Lysine MCF7 cell Malignant Neoplasms Mass Spectrum Analysis Measures Mediating Messenger RNA Minor Mitochondria Modeling Molecular Nitrosamines Normal Cell Outcome Oxidation-Reduction Oxidoreductase Pathway interactions Patients Pattern Peptide Hydrolases Peripheral Blood Mononuclear Cell Pharmaceutical Preparations Pilot Projects Preventive Property Prostaglandin-Endoperoxide Synthase Prostate Protein p53 Proteins Proto-Oncogenes Reaction Reporting Resistance Reverse Transcriptase Polymerase Chain Reaction Running Site Staging Stress TP53 gene Time Tissues Transferase Tumor Suppressor Proteins base cancer cell cancer therapy carcinogenesis cell type cigarette smoking cytotoxic design environmental chemical improved irinotecan neoplastic cell novel oncoprotein p21 pre-clinical preclinical study prevent promoter prophylactic protective effect research study response transcription factor treatment strategy tumor

项目摘要

DESCRIPTION (provided by applicant): A vast amount of epidemiological, preclinical and clinical studies have revealed aspirin as a promising chemopreventive agent, particularly in epithelial carcinogenesis. Despite the wide attention inhibition of cyclooxygenases has received, it is clear that aspirin elicits a myriad of molecular effects that counteract the carcinogenic episodes. Since aspirin's protective effect was mainly observed in epithelial cell types which are more resistant to chemotherapeutic efforts, an urgent need exists to dissect and identify the primary targets and cancer preventive pathways affected by aspirin. In preliminary studies, we have obtained the first and strong evidence for a dose- and time-dependent acetylation of p53 tumor suppressor protein by aspirin in MDA-MB-231 human breast cancer cells, several cancer cells belonging to different tumor types and also in normal liver cells. In MDA-MB-231 cells, aspirin induced the levels of p53 target genes namely p21CIP1, a protein involved in cell cycle arrest, and Bax, a proapoptotic protein; however, p21 induction was transient (1-12h); where as, induction of Bax was sustained (24 h). Interestingly, in DNA damaged cells (induced by camptothecin), aspirin treatment (24 h) inhibited the p21 induction, while the Bax induction was unaffected. Built on these findings, the central hypothesis of this R03 pilot project is that aspirin-induced multi-site acetylation of p53 alters its transcription factor function by shifting the gene expression spectrum from those that elicit cell cycle arrest / prosurvival properties to those that promote and drive cell death. Since deletion of p21 gene has been previously shown to increase the sensitivity of cells towards apoptosis, our observation that aspirin inhibits p21 suggests a potential mechanism by which it may exert anti-cancer effects in DNA damaged cells. The studies proposed in this application will determine the mechanisms by which aspirin regulates apoptosis in DNA damaged cells via inhibition of p21. We will use MDA-MB-231 and MCF-7 breast cancer cells as well as normal human Peripheral Blood Mononuclear Cells in our study. The experiments in Aim 1 will investigate the molecular basis of aspirin-mediated inhibition of p21 using real time RT-PCR, electrophoretic mobility shift assays, and run on transcription assays. We will also identify aspirin-induced acetylation sites on p53. In Aim II, we will determine the ability of aspirin to augment apoptosis in cells exposed to DNA damaging drugs by clonogenic cell survival assays and flow cytometry. In addition to camptothecin, all studies will be extended to include doxorubicin and cisplatin, to determine if aspirin also modulates p21 / Bax expression by these DNA damaging drugs. These studies will provide a novel mechanism by which aspirin may exert anticancer effects in DNA damaged cells via acetylation of p53, induction of Bax and inhibition of p21.

描述（由申请人提供）：大量流行病学、临床前和临床研究表明阿司匹林是一种有前途的化学预防剂，特别是在上皮癌发生方面。尽管环加氧酶的抑制作用受到了广泛关注，但阿司匹林显然会引发多种分子效应，从而抵消致癌作用。由于阿司匹林的保护作用主要在对化疗更有抵抗力的上皮细胞类型中观察到，因此迫切需要剖析和确定受阿司匹林影响的主要靶点和癌症预防途径。在初步研究中，我们获得了第一个有力的证据，证明阿司匹林对 MDA-MB-231 人乳腺癌细胞、属于不同肿瘤类型的几种癌细胞以及正常肝细胞。在 MDA-MB-231 细胞中，阿司匹林诱导 p53 靶基因的水平，即 p21CIP1（一种参与细胞周期停滞的蛋白质）和 Bax（一种促凋亡蛋白质）；然而，p21 诱导是短暂的（1-12 小时）；其中，Bax 的诱导持续（24 小时）。有趣的是，在 DNA 损伤细胞（由喜树碱诱导）中，阿司匹林治疗（24 小时）抑制了 p21 诱导，而 Bax 诱导不受影响。基于这些发现，该 R03 试点项目的中心假设是阿司匹林诱导的 p53 多位点乙酰化通过将基因表达谱从引发细胞周期停滞/促存活特性的基因转移到促进和促进细胞增殖的基因表达谱来改变其转录因子功能。驱动细胞死亡。由于 p21 基因的缺失先前已被证明会增加细胞对细胞凋亡的敏感性，因此我们对阿司匹林抑制 p21 的观察表明，它可能通过其在 DNA 受损细胞中发挥抗癌作用的潜在机制。本申请中提出的研究将确定阿司匹林通过抑制 p21 调节 DNA 损伤细胞凋亡的机制。我们将在我们的研究中使用 MDA-MB-231 和 MCF-7 乳腺癌细胞以及正常人外周血单核细胞。目标 1 中的实验将使用实时 RT-PCR、电泳迁移率变动分析以及转录分析来研究阿司匹林介导的 p21 抑制的分子基础。我们还将鉴定 p53 上阿司匹林诱导的乙酰化位点。在目标 II 中，我们将通过克隆细胞存活测定和流式细胞术确定阿司匹林增强暴露于 DNA 损伤药物的细胞凋亡的能力。除喜树碱外，所有研究都将扩展到阿霉素和顺铂，以确定阿司匹林是否也通过这些 DNA 损伤药物调节 p21/Bax 表达。这些研究将提供一种新的机制，阿司匹林可以通过 p53 的乙酰化、Bax 的诱导和 p21 的抑制来在 DNA 损伤的细胞中发挥抗癌作用。