Role of MSK1, ERa and Brf1 in alcohol-associated breast cancer

MSK1、ERa 和 Brf1 在酒精相关乳腺癌中的作用

• 批准号: 8539582
• 负责人: Shuping Zhong
• 金额: $ 22.91万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-05 至 2015-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8539582
• 关键词: Affect; Alcohols; Animal Model; Breast; Breast Cancer Cell; Cancer cell line; Cell Culture Techniques; Cell Line; Cell Nucleolus; Cell Proliferation; Cells; Chemicals; Critical Pathways; DNA Polymerase III; Development; Diagnostic; Dietary Factors; Dominant-Negative Mutation; Estradiol; Estrogen Receptors; Estrogen receptor positive; Ethanol; Event; Gene Expression; Genes; Genetic Transcription; Histone H3; Human; Hypertrophy; In Situ; In Vitro; JUN gene; Knockout Mice; Lead; Ligands; Link; MCF7 cell; Malignant Neoplasms; Mammary Gland Parenchyma; Mediating; Mitogen-Activated Protein Kinases; Molecular; Neoplasms; Nude Mice; Pathologist; Pathway interactions; Phosphorylation; Play; Polymerase; Polymerase Gene; RNA Polymerase I; RNA Polymerase III; Repression; Research Design; Ribosomal RNA; Role; Serine; Signal Transduction; Signaling Molecule; Small Interfering RNA; Testing; Time; Transcription Factor TFIIIB; Transfer RNA; Tumor Tissue; Untranslated RNA; Wild Type Mouse; Work; alcohol response; cancer cell; cancer risk; cell transformation; chronic alcohol ingestion; feeding; in vivo; inhibitor/antagonist; knock-down; malignant breast neoplasm; mitogen and stress-activated protein kinase 1; mutant; neoplastic cell; novel; novel strategies; novel therapeutics; overexpression; public health relevance; response; small hairpin RNA; synthetic protein; tumor; tumor growth; tumorigenesis

DESCRIPTION (provided by applicant): Alcohol is the dietary factor, which is most consistently associated with breast cancer risk. This association involves the estrogen receptor (ER), which is over-expressed (ER+) in around 80% of breast cancer cases. Alcohol-association is more pronounced in ER(+) breast cancer cases than in ER(-) breast cancer cases, however, the molecular mechanism remains to be determined. Cancer cells have a consistent cytological feature of nucleolar hypertrophy, where rRNAs are synthesized by RNA polymerases (Pol) I and Pol III. Pathologists have been using enlarged nucleoli as a diagnostic indicator of cell transformation and neoplasia. It indicates that transformation in situ is tightly linked to the deregulation of RNA Pol I and III gene transcription, because the size of the nucleolus reflects the levels of rRNA synthesis. RNA Pol III is responsible for the synthesis of a variety of untranslated RNAs, including 5S rRNAs and tRNAs. Deregulation of RNA Pol III-dependent genes (Pol III genes) would serve to enhance the translational capacity of cells, which is required to promote cell transformation and tumor development. Alcohol-induced deregulation of Pol III genes may be fundamental to the development of breast cancer. Our previous studies demonstrated that MAP kinases modulated Brf1 and TBP expression and Pol III gene transcription and mediated phosphorylation of histone H3 (H3ph). Our recent studies have demonstrated that ethanol activates MAP kinase and induces Pol III gene transcription through enhanced TBP and c-Jun expression by using cell culture and an animal model. Preliminary results have revealed that alcohol induces Pol III gene transcription in both normal breast and breast cancer cell lines. However, the induction in breast cancer cells (5-6 fold) is higher than i normal breast cells (2.5 fold). Further analysis indicates that the induction is ER dependent. The ER ligand, E2 (17b-estradiol) causes an induction (< 2 fold) of these genes, whereas ethanol works with E2 to create an additional increase (12 fold) in Pol III gene transcription, resulting i cell proliferation and transformation. Alcohol activated MSK1 (mitogen- and stress-activated protein kinase 1), a downstream component of MAP kinases, which mediates phosphorylation of histone H3 (H3ph) at serine 10 (H3S10ph) and serine 28 (H3S28ph) and modulates gene expression and cell transformation. Thus, we hypothesize that alcohol activates MSK1, which mediates H3ph. H3ph in turn upregulates Brf1 expression and Pol III gene transcription to enhance the protein synthetic capacity of cells, which can eventually lead to ERa-dependent breast cancer. This implies that the induction by alcohol may be an early event, contributing to the development of ER(+) breast cancer. By using cell culture and animal models, we will determine: 1) if alcohol-activated MSK1 mediates Brf1 expression and Pol III gene transcription, which in turn causes phenotypic changes, and if inhibition of MSK1 by its chemical inhibitor and shRNA or using a MSK KO mouse blocks alcohol-induced cell transformation and Pol III gene transcription; 2) if alcohol-induced H3ph modulates Brf1 and Pol III gene expression and cell transformation; 3) if alteration of ERa and Brf1 expression affects transcription of Pol III genes and if blocking Brf1 expression by its shRNA inhibits tumor formation in nude mouse upon administration of alcohol or alcohol plus E2. These studies are designed to determine the molecular mechanism of alcohol- induced deregulation of Pol III genes in the development of ER+ breast cancer. Investigating the effects of MSK1 and Brf1 shRNAs on tumor formation may provide a new approach to inhibit tumor growth. Our overall objective is to investigate the role of MSK1 and Brf1 in the alcohol-induced response that may be critically important in ER+ breast cancer development.

描述（由申请人提供）：酒精是饮食因素，与乳腺癌风险最相关。这种关联涉及雌激素受体（ER），其在约80%的乳腺癌病例中过度表达（ER+）。酒精相关性在ER（+）乳腺癌病例中比在ER（-）乳腺癌病例中更明显，然而，分子机制仍有待确定。癌细胞具有一致的核仁肥大的细胞学特征，其中rRNA由RNA聚合酶（Pol）I和Pol III合成。病理学家一直使用增大的核仁作为细胞转化和肿瘤形成的诊断指标。这表明原位转化与RNA Pol I和III基因转录的失调密切相关，因为核仁的大小反映了rRNA合成的水平。RNA Pol III负责合成多种非翻译RNA，包括5S rRNA和tRNA。RNA Pol III依赖性基因（Pol III基因）的失调将有助于增强细胞的翻译能力，这是促进细胞转化和肿瘤发展所必需的。酒精诱导的Pol III基因失调可能是乳腺癌发展的基础。我们以前的研究表明，MAP激酶调节Brf 1和TBP的表达和Pol III基因的转录，并介导组蛋白H3（H3 ph）的磷酸化。我们最近的研究表明，乙醇激活MAP激酶，并通过使用细胞培养和动物模型增强TBP和c-Jun表达诱导Pol III基因转录。初步结果显示，酒精诱导Pol III基因在正常乳腺和乳腺癌细胞系中的转录。然而，乳腺癌细胞中的诱导（5-6倍）高于正常乳腺细胞（2.5倍）。进一步的分析表明，诱导是ER依赖性的。ER配体E2（17 b-雌二醇）引起这些基因的诱导（< 2倍），而乙醇与E2一起作用以产生Pol III基因转录的额外增加（12倍），导致细胞增殖和转化。酒精激活的MSK 1（促分裂原和应激激活蛋白激酶1），MAP激酶的下游组分，介导组蛋白H3（H3 ph）在丝氨酸10（H3 S10 ph）和丝氨酸28（H3 S28 ph）的磷酸化，并调节基因表达和细胞转化。因此，我们假设酒精激活介导H3 ph的MSK 1。H3 ph反过来上调Brf 1表达和Pol III基因转录，以增强细胞的蛋白质合成能力，最终导致ER α依赖性乳腺癌。这意味着酒精诱导可能是早期事件，有助于ER（+）乳腺癌的发展。通过细胞培养和动物模型，我们将确定：1）酒精激活的MSK 1是否介导Brf 1表达和Pol III基因转录，从而导致表型变化，以及通过其化学抑制剂和shRNA或使用MSK KO小鼠抑制MSK 1是否阻断酒精诱导的细胞转化和Pol III基因转录; 2）酒精诱导的H3 ph是否调节Brf 1和Pol III基因表达和细胞转化;第三章如果ER α和Brf 1表达的改变影响Pol III基因的转录，并且如果通过其shRNA阻断Brf 1表达抑制了在给予酒精或酒精加E2这些研究旨在确定ER+乳腺癌发展中酒精诱导的Pol III基因失调的分子机制。研究MSK 1和Brf 1 shRNA对肿瘤形成的影响可能为抑制肿瘤生长提供新的途径。我们的总体目标是研究 MSK 1和Brf 1在酒精诱导的反应中可能对ER+乳腺癌的发展至关重要。