Growth Regulatory Mechanisms of KLF in Barrett's Epithelium

KLF 在 Barrett 上皮细胞中的生长调节机制

• 批准号: 7745464
• 负责人: NAVTEJ S BUTTAR
• 金额: $ 12.61万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-01-15 至 2011-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7745464
• 关键词: Acids; Acute; Adenocarcinoma; Adenoviruses; Animal Model; Animals; Apoptosis; Arachidonic Acids; Arts; Barrett Epithelium; Barrett Esophagus; Bile Reflux; Binding; Binding Sites; Biochemical; Caucasians; Caucasoid Race; Cell Culture Techniques; Cell Cycle; Cellular biology; Chronic; Clinic; Columnar Epithelium; Development; Dinoprostone; Down-Regulation; Environment; Epithelial Cells; Esophageal; Esophagus; Family; GC Rich Sequence; Gastroesophageal reflux disease; Gene Expression; Gene Expression Regulation; Gene Targeting; Genes; Glucocorticoids; Goals; Growth; Growth Factor; Injury; Knowledge; Kruppel protein; Malignant - descriptor; Malignant Neoplasms; Mediating; Membrane; Mentored Clinical Scientist Development Award (K08); Mentors; Metaplastic; Methodology; Molecular; Mucous Membrane; Mus; Neoplasms; Neoplastic Cell Transformation; Pathway interactions; Patients; Phospholipase A2; Phospholipids; Phosphorylation; Principal Investigator; Process; Production; Promoter Regions; Proteins; Reflux; Regulation; Regulator Genes; Regulatory Element; Risk; Role; Site; Sp1 Transcription Factor; Squamous Epithelium; TNFSF11 gene; Techniques; Testing; Transcription Factor AP-1; Transgenic Organisms; Tumor Suppressor Proteins; Up-Regulation; base; bile salts; career; cytokine; design; in vivo; male; member; neoplastic; novel; nuclear factor 1; outcome forecast; preclinical study; prevent; programs; promoter; skills; transcription factor; tumor; villin

Barrett's esophagus is a pre-neoplastic condition in which the normal squamous epithelium is replaced by metaplastic columnar epithelium in the lower esophagus as a result of chronic esophageal reflux injury. This reflux related injury has been implicated in the development of highly lethal adenocarcinoma in Barrett's mucosa which is one of the most rapidly increasing cancers. Thus, understanding the mechanisms of neoplastic transformation in Barrett's esophagus is of great importance. Contents of reflux activate PGE2 synthesis in Barrett's esophagus. We and others have noted that high levels of PGE2 promote neoplastic transformation in Barrett's esophagus. However, the details of the underlying molecular mechanisms remain unclear. The rate-limiting step in the PGE2 synthesis pathway is the release of arachidonic acid from the membrane phospholipids by phospholipase A2, particularly cPLA2-a (cytosolic PLA2-a). The promoter region of cPLA2-a has GC-rich regions to which the members of SP/KLF (stimulatory protein/ Kruppel like factors) family of transcription factors can bind. In preliminary studies, we made the following novel observations that 1) KLF11 acts as a represser of the cPLA2-a promoter activity and decreases PGE2 production, 2) KLF11 down-regulates the growth of malignant Barrett's epithelial cells, 3) the growth inhibitory effect of KLF11 is associated with up-regulation of the expression growth regulatory genes in malignant Barrett's epithelial cells, and 4) there is pronounced loss of KLF11 expression during the progression of neoplasia in Barrett's esophagus. Based on these observations, our CENTRAL HYPOTHESIS is that KLF11 behaves as a tumor suppressor by a dual mechanism involving inhibition of PGE2 synthesis by repressing cPLA2a promoter activity and also via regulation of genes involved in the cell cycle and apoptosis in Barrett's epithelium. To assess this we will use three specific aims. FIRST, we will examine the molecular mechanisms of KLF11-mediated inhibition of PGE2 pathway in Barrett's epithelium. SECOND, we will assess the PGE2 dependent and independent cellular mechanisms of the tumor suppressive role of KLF11 in Barrett's epithelium. THIRDLY, we will determine the in vivo relevance of KLF11 on the neoplastic transformation in Barrett's mucosa by using KLF- /- mice with reflux. This mechanistic, hypothesis-driven study will use state-of-the art methodology and has significant translational relevance. In this KO8 Mentored Clinical Scientist Development Award, I will acquire a comprehensive, in depth knowledge of molecular cell biology and biochemical techniques to mechanistically answer the pathophysiological questions. These skills will allow me to launch a productive independent investigative career. The mentoring environment at Mayo Clinic is conducive to successfully accomplish these goals.

巴雷特的食道是一种前塑性疾病，其中正常的鳞状上皮被取代 慢性食管反流损伤导致下食管下的柱状柱状上皮。这 反流相关的损伤与巴雷特的高致命腺癌的发展有关 粘膜是最快增加的癌症之一。因此，了解机制 巴雷特食管中的肿瘤转化非常重要。反流的内容激活PGE2 巴雷特食道的合成。我们和其他人指出，高水平的PGE2促进了肿瘤 巴雷特食管的转变。但是，基本分子机制的细节仍然存在 不清楚。 PGE2合成途径中的速率限制步骤是从 磷脂酶A2的膜磷脂，尤其是CPLA2-A（胞质PLA2-A）。发起人 CPLA2-A的区域具有富含GC的区域，SP/ KLF成员（刺激蛋白/ Kruppel） 因素）转录因子家族可能会结合。 在初步研究中，我们提出了以下新颖的观察结果，即1）klf11充当阻遏者 CPLA2-A启动子活性并降低PGE2的产生，2）KLF11下调的生长 恶性Barrett的上皮细胞，3）KLF11的生长抑制作用与上调有关 恶性Barrett上皮细胞中的表达生长调节基因，4） 在巴雷特食管中肿瘤进展过程中KLF11表达的丧失。基于这些 观察结果，我们的中心假设是KLF11通过双重抑制肿瘤 通过抑制CPLA2A启动子活性以及通过 调节Barrett上皮细胞周期中涉及的基因和凋亡。为了评估这一点，我们将使用 三个具体目标。首先，我们将检查KLF11介导的抑制的分子机制 Barrett上皮的PGE2途径。其次，我们将评估PGE2依赖和独立 KLF11在Barrett上皮的肿瘤抑制作用的细胞机制。第三，我们会的 通过使用KLF-来确定KLF11在Barrett粘膜中的肿瘤转化的体内相关性 / - 倒流的小鼠。这项机械性，假设驱动的研究将使用最先进的方法论，并具有 重大的翻译相关性。在这个KO8指导的临床科学家发展奖中，我将获得 对分子细胞生物学和生化技术的全面知识 机械地回答病理生理问题。这些技能将使我能够发起富有成效的 独立的调查生涯。梅奥诊所的指导环境有利于成功 实现这些目标。