Mechanisms Involved in Mammary Morphogenesis

乳腺形态发生的机制

• 批准号: 6989354
• 负责人: Joan Siefert Brugge
• 金额: $ 14.87万
• 依托单位: WHITEHEAD INSTITUTE FOR BIOMEDICAL RES
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-03-16 至 2009-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6989354
• 关键词: BCL2 gene /protein; acinar cell; apoptosis; carcinogenesis; carcinoma; cell line; gene induction /repression; histogenesis; mammary epithelium; mammary gland; neoplasm /cancer genetics; neoplastic growth

The filling of a hollow lumen within an intact glandular structure is a hallmark of early tumorigenesis. However the mechanisms involved in the formation of a glandular lumen and its filling during the development of carcinoma-in-situ are poorly understood. We have developed an in vitro three-dimensional (3D) culture model to investigate alterations in the architecture and growth properties of glandular epithelial structures (acini) during early stages of mammary carcinogenesis. We have found that formation of the lumen involves selective death of cells in the center of the acini. Filling of the luminal space, as provoked by oncogenes, requires not only induction of constitutive proliferation but also anti-apoptotic signals that allow cells to survive in the luminal space. We have identified the proapoptotic Bcl-2 protein Bim as critical mediator of apoptosis during lumen formation and found that its expression is regulated by oncogenes that escape death in the luminal space. Bim was also found to be induced and critically involved in apoptosis induced by detachment of monolayer cells from matrix (a process referred to as anoikis) and several lines of evidence suggest that matrix deprivation may be involved in luminal cell death during morphogenesis. This proposal describes plans to elucidate the mechanisms that regulate cell death induced by Bim during both lumen formation and anoikis, identify other proteins that collaborate with Bim to mediate cell death, and determine the mechanisms whereby oncogenes allow cells to escape cell death induced by these apoptotic mediators. This study should provide important information relating to events associated with the development of carcinoma-in-situ tumors in humans. These investigations should provide important information relating to events associated with the development of carcinoma-in-situ tumors in humans. Studies to examine the regulation of Bim during anoikis, lumen formation and oncogenesis will involve investigations of the mechanism involved in Bim induction and activation in both models, analysis of how Bim is downregulated or inactivated by oncogenes, and elucidation of the basis for protection of mammary epithelial cells from Bim-induced death operating in acinar cells that are attached to matrix. Identification of other proapoptotic proteins will involve affinity isolation techniques as well as strategies that induce loss of function of other pro-apoptotic proteins. We will use retroviral genetic screens to identify additional proteins that protect cells from detachment induced death or luminal clearing in acini. Lastly, we will examine whether the processes that we define in the immortalized MCF-10A cells are operative in primary human cells.

完整腺结构内的空心管腔的填充是早期肿瘤发生的标志。然而，对腺体腔形成及其在现场癌发展过程中填充涉及的机制知之甚少。我们已经开发了一种体外三维（3D）培养模型，以研究乳腺上皮结构（ACINI）的结构和生长特性的改变。 致癌作用。我们发现，管腔的形成涉及在acini中心的细胞选择性死亡。肿瘤基因引起的腔内空间的填充不仅需要诱导构型增殖，还需要抗凋亡信号，允许细胞在腔内空间中生存。我们已经确定促凋亡的Bcl-2蛋白BIM是管腔形成过程中细胞凋亡的关键介体，发现其表达受Oncogenes调节 那逃避了腔内空间中的死亡。还发现BIM是由单层细胞脱离基质（一种称为Anoikis的过程）引起的，并参与了凋亡，并且有几种证据表明，在形态发生过程中，基质剥夺可能与腔细胞死亡有关。该提案描述了阐明调节BIM在管腔形成和Anoikis期间BIM诱导的细胞死亡的机制的计划，请识别 与BIM合作以介导细胞死亡的其他蛋白质，并确定癌基因允许细胞逃脱这些凋亡介质引起的细胞死亡的机制。这项研究应提供与与人类癌肿瘤发展有关的事件有关的重要信息。这些研究应提供与与人类癌癌发展有关的事件有关的重要信息。 研究在ANOIKIS期间检查BIM的调节，管腔形成和肿瘤发生将涉及对BIM诱导和激活中涉及的机制进行研究，分析BIM如何被Oncogenes下调或灭活，并阐明对BIM诱导死亡的乳腺上皮细胞的基础，该基础是附着在Bim诱导的死亡中，该细胞附着在脂肪中，对脂肪诱导的生死亡量是依次的。鉴定其他促凋亡蛋白将涉及亲和力隔离技术以及诱导其他促凋亡蛋白功能丧失的策略。我们将使用逆转录病毒遗传筛选来鉴定额外的蛋白质，以保护细胞免受脱离诱导的死亡或腔内清除。最后，我们将检查我们在永生的MCF-10A细胞中定义的过程是否在原代人类细胞中可操作。