Role of Protein (S14)in Normal and Neoplastic Mammary

蛋白质 (S14) 在正常和肿瘤乳腺中的作用

• 批准号: 6721367
• 负责人: WILLIAM B KINLAW
• 金额: $ 24.49万
• 依托单位: DARTMOUTH COLLEGE
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-01 至 2006-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6721367
• 关键词: DNA binding protein; MCF7 cell; apoptosis; athymic mouse; breast neoplasms; carcinogenesis; cell differentiation; cell proliferation; cyclins; fatty acid biosynthesis; fatty acid synthase; gel mobility shift assay; gene deletion mutation; gene expression; gene targeting; genetic promoter element; genetically modified animals; lactation; lipid metabolism; liver cells; mammary epithelium; neoplastic cell; nuclear proteins; nucleoproteins; oncogenes; protein metabolism; protein structure function; transcription factor

Abundant expression of enzymes of fatty acid synthesis occurs for each cycle of lactation and in a subset of aggressive breast cancers. S14 is a hormonally-inducible nuclear protein expressed only in tissues actively synthesizing lipids for use as a fuel (lactating mammary, liver, adipose), and is required for induction of genes coding lipogenic enzymes in response to hormonal and dietary signals. S14 is expressed in human mammary epithelium only during lactation, and we find it is critical for lipid metabolism, growth, and survival of mammary epithelial and lipogenic breast cancer cells. Genes coding S14 and Cyclin D1, a mammary oncogene that is also key for normal mammary development, both reside on the l lq13 cancer amplicon. In addition to S14 gene amplification, we find S14 overexpression in the majority of tumors, as is the case for cyclin D1. S14 expression correlates with that of a key lipogenic enzyme (acetyl-CoA carboxylase) in tumors, and is induced by progestin in breast cancer cells in concert with fatty acid synthase (FAS). This proposal is focused on the hypothesis that increased fatty acid synthesis in both lactating and malignant mammary cells is mediated by S14 and that this is critical for cell proliferation. We propose four specific aims: First, to define the impact of S14 expression on growth and metabolism of cells derived from normal mammary epithelium and from breast cancer. S14 expression and antisense genes will be introduced into HC11 lactating mouse mammary epithelial- and human breast cancer cells. Lipid synthesis, expression of lipogenic enzymes and their mRNAs, and growth/cell cycle effects will be analyzed in tissue culture and in xenografts in nude mice. Second, to define the functional interaction of S14 arid a key transcription factor (SREBP1c) that induces S14 and other genes for lipid synthesis and is also required for survival of lipogenic breast cancer cells. Regulation of FAS gene transcription by S14 and SREBP1c will be assessed by deletion analysis, and protein-DNA interactions will be identified. Third, to determine whether S14 drives mammary lipogenesis in vivo, and whether it acts as an oncogene, either alone or in cooperation with cyclin Dl. MMTV-S14 transgenic mice will be assessed metabolically and for tumorigenesis. In addition, MMTV-S14 mice will be crossed with a MMTV-cyclin D1 strain to determine if metabolism and/or virulence of cyclin D 1-induced tumors are influenced by S14. Fourth, to assess the role of S14 in mammary metabolism and development in mice with mammary-specific S14 gene disruption. These studies will provide a comprehensive view of the role of this novel nuclear protein in both normal mammary physiology and in breast cancer, and are likely to reveal a new class of therapeutic targets.

每个哺乳周期和一部分侵袭性乳腺癌中都会出现脂肪酸合成酶的大量表达。 S14 是一种激素诱导型核蛋白，仅在积极合成用作燃料的脂质的组织（哺乳期乳房、肝脏、脂肪）中表达，并且是诱导编码脂肪生成酶的基因响应激素和饮食信号所必需的。 S14 仅在哺乳期在人类乳腺上皮中表达，我们发现它对于乳腺上皮和脂肪生成乳腺癌细胞的脂质代谢、生长和存活至关重要。编码 S14 和 Cyclin D1 的基因（一种乳腺癌基因，也是正常乳腺发育的关键）均位于 l lq13 癌症扩增子上。除了 S14 基因扩增之外，我们还发现大多数肿瘤中 S14 过度表达，细胞周期蛋白 D1 也是如此。 S14 的表达与肿瘤中关键的脂肪生成酶（乙酰辅酶 A 羧化酶）的表达相关，并且由乳腺癌细胞中的孕激素与脂肪酸合酶 (FAS) 协同诱导。该提案的重点是这样的假设：泌乳和恶性乳腺细胞中脂肪酸合成的增加是由 S14 介导的，这对于细胞增殖至关重要。我们提出了四个具体目标：首先，确定 S14 表达对正常乳腺上皮和乳腺癌细胞生长和代谢的影响。 S14 表达和反义基因将被引入 HC11 哺乳小鼠乳腺上皮癌细胞和人乳腺癌细胞中。将在组织培养物和裸鼠异种移植物中分析脂质合成、脂肪生成酶及其 mRNA 的表达以及生长/细胞周期效应。其次，确定 S14 和关键转录因子 (SREBP1c) 的功能相互作用，该转录因子诱导 S14 和其他基因进行脂质合成，并且也是脂肪生成乳腺癌细胞存活所必需的。将通过缺失分析评估 S14 和 SREBP1c 对 FAS 基因转录的调节，并鉴定蛋白质-DNA 相互作用。第三，确定S14是否在体内驱动乳腺脂肪生成，以及它是否单独或与细胞周期蛋白D1协同作用作为癌基因。将评估 MMTV-S14 转基因小鼠的代谢和肿瘤发生情况。此外，MMTV-S14 小鼠将与 MMTV-细胞周期蛋白 D1 品系杂交，以确定细胞周期蛋白 D 1 诱导的肿瘤的代谢和/或毒力是否受到 S14 的影响。第四，评估 S14 在乳腺特异性 S14 基因破坏的小鼠乳腺代谢和发育中的作用。这些研究将全面了解这种新型核蛋白在正常乳腺生理学和乳腺癌中的作用，并可能揭示一类新的治疗靶点。