Mechanistic regulation of tumor specific forms of cyclin E in breast cancer

乳腺癌中肿瘤特定形式的细胞周期蛋白 E 的机制调节

• 批准号: 7882549
• 负责人: NIKKI A DELK
• 金额: $ 5.17万
• 依托单位: RICE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-05-01 至 2011-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7882549
• 关键词: Adverse effects; Area; Binding; Binding Proteins; Biochemical; Biological Assay; Breast; Breast Cancer Cell; Cancer cell line; Cell Cycle; Cell Cycle Deregulation; Cell Cycle Proteins; Cell Cycle Regulation; Cell Proliferation; Cells; Cellular Morphology; Characteristics; Colorectal Cancer; Complex; Cyclin E; Cyclin-Dependent Kinase Inhibitor; Cyclins; Cytology; Development; E protein; Endometrial; Enzymes; Epithelial; F-Box Proteins; Genetic; Genomic Instability; Hair Cells; In Vitro; Lead; Length; Lymphocyte; Malignant Neoplasms; Mammary gland; Mediating; Molecular Weight; Mutation; Neoplasm Metastasis; Normal Cell; Oncogenic; Ovarian; Pathway interactions; Phase; Phase Transition; Phenotype; Phosphotransferases; Process; Proliferating; Property; Protein Binding; Protein Isoforms; Proteins; Regulation; Regulatory Pathway; Signaling Molecule; Specificity; Testing; Transgenic Mice; Translations; Tumor Cell Line; cancer therapy; cancer type; cyclin G1; high throughput screening; human CDK2 protein; malignant breast neoplasm; neoplastic; neoplastic cell; novel; pancreatic neoplasm; treatment strategy; tumor; tumor specificity; ubiquitin-protein ligase

DESCRIPTION (provided by applicant): Cell cycle deregulation is a distinct characteristic of neoplastic versus normal cells. Therefore, understanding the mechanisms that govern the regulation of cell cycle proteins is integral to developing treatment strategies that specifically target tumor cells. Cyclin E, a cell cycle protein that mediates GO release and G1 to S phase transition, shows a unique tumor-specific deregulation associated with malignancy in breast, ovarian, and colorectal cancers. In particular, full length wild-type cyclin E is processed into lower molecular weight isoforms in many types of cancers. The low molecular weight (LMW) isoforms result from proteolytic cleavage or alternative translation of full length cyclin E. LMW cyclin E isoforms induce early G1 to S phase transition, prolonged S phase, genomic instability, increase cell proliferation, metastasis, and altered cell morphology and development in immortalized mammary epithelial and breast cancer cell lines and transgenic mice. LMW cyclin E-induced phenotypes are due in part to enhanced cyclin dependent kinase (Cdk)-2 binding, associated hyperactive kinase activity, and reduced sensitivity to Cdk inhibitors. Therefore, inhibiting LMW cyclin E activity and restoring proper cyclin E cell cycle regulation may potentially alleviate malignancy in multiple types of cancers. The E3 ubiquitin ligase specificity factor, Fbw7, is an F-box protein that binds to and mediates cyclin E degradation in normal cells, making Fbw7 a candidate protein to inhibit LMW cyclin E activity in tumor cells. Mutations at the Fbw7 locus have been correlated with some breast, endometrial, and pancreatic tumors and cell lines and wild type Fbw7 expression can restore cyclin E regulation in breast cells. However, the mechanism of Fbw7 regulation of full length versus LMW cyclin E isoforms in tumor cells remains to be elucidated. We hypothesize that LMW cyclin E isoforms have altered interaction with cyclin E binding proteins, including Fbw7, and interact with novel proteins, thereby rendering the LMW cyclin E isoforms oncogenic. We propose to determine the mechanism of Fbw7 regulation of full length versus LMW cyclin E isoforms including effects on cyclin E stability, kinase activity, and cell cycle regulation using immunohistochemisty, in vitro enzyme assays, and cytology. We also propose to perform a novel, high throughput screen to identify full length and LMW cyclin E interactors and characterize the cellular and biochemical properties of these cyclin E complexes. Elucidation of the signaling molecules or pathways that regulate cyclin E stability and function can lead to rational approaches to target aberrant cyclin E expression in tumors.

描述（由申请人提供）：细胞周期放松管制是肿瘤与正常细胞的独特特征。因此，了解控制细胞周期蛋白调节的机制对于开发专门针对肿瘤细胞的治疗策略不可或缺。 Cyclin E是一种介导GO释放的细胞周期蛋白，并将G1释放到S相变，显示出与乳腺癌，卵巢和结直肠癌的恶性肿瘤相关的独特肿瘤特异性管制。特别是，在许多类型的癌症中，全长野生型细胞周期蛋白E被处理成低分子量同工型。低分子量（LMW）同工型是由蛋白水解裂解或全长细胞周期蛋白的替代翻译引起的。LMW环蛋白E同工型诱导早期的G1对S相过渡，长时间的S相，基因组不稳定性，基因组不稳定性，细胞增殖，转移的细胞和发育及其乳腺癌和植物的乳化菌丝和跨性别的乳皮菌和变化。 LMW细胞周期蛋白E诱导的表型部分归因于增强的细胞周期蛋白依赖性激酶（CDK）-2结合，相关的多活化激酶活性以及对CDK抑制剂的敏感性降低。因此，抑制LMW细胞周期蛋白活性并恢复适当的细胞周期细胞周期调节可能会减轻多种类型的癌症的恶性肿瘤。 E3泛素连接酶特异性因子FBW7是一种F-box蛋白，可与正常细胞中的细胞周期蛋白结合并介导细胞周期蛋白E降解，使FBW7成为候选蛋白，可抑制肿瘤细胞中LMW细胞周期蛋白E活性。 FBW7基因座的突变与某些乳房，子宫内膜和胰腺肿瘤以及细胞系以及野生型FBW7表达相关，可以恢复乳腺细胞中的细胞周期蛋白E调节。然而，肿瘤细胞中FBW7调节全长与LMW细胞周期E同工型的机制尚待阐明。我们假设LMW细胞周期蛋白E同工型改变了与细胞周期蛋白结合蛋白（包括FBW7）的相互作用，并与新型蛋白质相互作用，从而使LMW Cyclin e同工型致癌。我们建议使用免疫组织化学，体外酶测定法和细胞学学确定FBW7调节全长与LMW细胞周期E同工型的机制，包括对细胞周期蛋白E稳定性，激酶活性和细胞周期调节的影响。我们还建议执行一种新型的高吞吐量筛选，以识别全长和LMW Cyclin E相互作用者，并表征这些细胞周期蛋白E复合物的细胞和生化特性。阐明调节细胞周期蛋白E稳定性和功能的信号分子或途径可以导致靶向肿瘤中异常细胞周期蛋白E表达的合理方法。