Role of microRNAs in genetic mouse models of pancreatic cancer

microRNA在胰腺癌遗传小鼠模型中的作用

• 批准号: 7614143
• 负责人: Murray Korc
• 金额: $ 24.34万
• 依托单位: DARTMOUTH COLLEGE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7614143
• 关键词: Affect; Alleles; Anchorage-Independent Growth; Animals; Apoptosis; Biological Markers; CDKN2A gene; Cancer Biology; Cancer Etiology; Cancer cell line; Cancerous; Carcinoma; Cell Line; Cell physiology; Cells; Cellular Assay; Cessation of life; Clinical; Collection; Development; Diagnosis; Dicer Enzyme; Disease Progression; Early Diagnosis; Enzymes; Epigenetic Process; Exhibits; Exploratory/Developmental Grant; Functional RNA; Gene Expression; Gene Targeting; Generations; Genes; Genetic; Genotype; Heterogeneity; Human; In Situ Hybridization; In Vitro; Incidence; Individual; Intraepithelial Neoplasia; Knock-in Mouse; Lesion; Link; Malignant Neoplasms; Malignant neoplasm of pancreas; Mediating; MicroRNAs; Modeling; Molecular; Molecular Profiling; Mus; Mutate; Mutation; Northern Blotting; Pancreas; Pancreatic Ductal Adenocarcinoma; Pancreatic Intraepithelial Neoplasia; Patients; Plasmids; Porifera; Process; Regulation; Regulator Genes; Regulatory Pathway; Reporting; Resistance; Role; Signal Pathway; Specimen; Staging; Subfamily lentivirinae; Suggestion; System; TP53 gene; Testing; Therapeutic; Therapeutic Agents; Time; Transgenes; Transgenic Animals; Transgenic Organisms; Tumor Suppressor Genes; Tumor Tissue; United States; Ursidae Family; base; cancer cell; cell type; chemotherapy; combinatorial; genetic manipulation; genome-wide; human DICER1 protein; locked nucleic acid; loss of function; loss of function mutation; mortality; mouse model; neoplastic cell; new therapeutic target; novel; novel therapeutics; outcome forecast; overexpression; pancreatic tumorigenesis; public health relevance; research study; response; tool; tumor; tumorigenesis; tumorigenic

DESCRIPTION (provided by applicant): Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer death in the United States. Because of its stubborn resistance to chemotherapy, there is an urgent need to develop novel therapeutic strategies for this deadly cancer. Numerous studies have revealed an important etiological contribution of activated mutations of K-ras and loss of function mutations of p16, p53 and Smad4. Mouse models that combine mutations in these genes have permitted their study specifically in the context of the pancreas thanks to the Cre/LoxP system. However, the potential role of other regulatory pathways, either with respect to the development of PDAC and/or in relation to the genesis of its marked chemoresistance, has not been thoroughly investigated. MicroRNAs (miRNAs) are a new class of short non-coding RNA genes [10-12], which act as post- transcriptional negative regulators of gene expression [13]. MiRNA-mediated regulation of tumorigenesis is emerging as a new paradigm in the field of cancer biology. The large number of predicted target genes for each miRNA suggests that miRNAs could provide a novel and global mechanism to modulate gene expression comparable to genome-wide epigenetic and transcriptional changes associated with cancer. Moreover, several reports indicate that specific miRNAs exhibit functions reminiscent of tumor suppressors and oncogenes. In addition, global decreases in miRNA activity by loss of Dicer or other enzymes required for miRNA processing result in enhanced tumorigenic potential, reflecting on the overall role of miRNAs in mediating tumor suppressive functions. Our preliminary studies and reports from other groups have linked a subset of miRNAs to PDAC based on: 1) their differential expression in pancreatic cell lines and/or in clinical specimens and/or 2) their interaction with signaling pathways etiologically relevant such as K-Ras, p16 and p53. Thus, miRNAs could serve as useful biomarkers for early detection, diagnosis and/or prognosis, advance our understanding of the molecular mechanisms of tumorigenesis, and serve as novel therapeutic targets. Based on these observations, our overall hypothesis is that miRNAs exert a crucial role in the initiation and progression of PDAC and that combinatorial therapy with current therapeutic agents and synthetic modulators of this novel class of regulatory RNAs may provide an effective strategy to increase patient response to treatment. We have established several transgenic murine strains that bear conditional mutations in K-ras and/or p16 genes, the most frequently mutated genes in PDAC, and we propose to conduct a functional analysis of miRNAs aimed at assessing: 1) The effect of decreased global miRNA activity in disease progression by crossing a conditional loss of function dicer1floxed/floxed animal to cancer-prone animals bearing mutated alleles of K-ras and/or p16 genes. 2) The contribution of individual miRNAs to pancreatic tumorigenesis in vitro by manipulating levels of miRNA expression/activity in murine and human pancreatic cancer cell lines. PUBLIC HEALTH RELEVANCE: Pancreatic ductal adenocarcinoma (PDAC) is a deadly malignancy in which mortality virtually equals incidence, yet for which there are no satisfactory therapeutic treatments. Emerging evidence suggests a pivotal role of microRNAs in cancer biology. We hypothesize that combinatorial therapy of current chemotoxic compounds and synthetic modulators of this novel class of regulatory RNAs may provide an effective strategy to increase patient response to treatment. In this proposal, we will investigate the etiological contribution of microRNAs to PDAC and conduct a preliminary assessment of their potential therapeutic application.

描述（由申请人提供）：胰腺导管腺癌（PDAC）是美国第四大癌症死亡原因。由于其对化疗具有顽固的抵抗力，因此迫切需要为这种致命的癌症开发新的治疗策略。大量研究揭示了 K-ras 激活突变和 p16、p53 和 Smad4 功能丧失突变的重要病因学贡献。得益于 Cre/LoxP 系统，结合了这些基因突变的小鼠模型使得他们能够在胰腺的背景下进行专门的研究。然而，其他调控途径的潜在作用，无论是与 PDAC 的发展和/或与其显着化学耐药性的起源有关，尚未得到彻底研究。 MicroRNA (miRNA) 是一类新的短非编码 RNA 基因 [10-12]，充当基因表达的转录后负调节因子 [13]。 miRNA 介导的肿瘤发生调节正在成为癌症生物学领域的新范例。每个 miRNA 的大量预测靶基因表明，miRNA 可以提供一种新颖的全局机制来调节基因表达，类似于与癌症相关的全基因组表观遗传和转录变化。此外，一些报告表明特定的 miRNA 表现出类似肿瘤抑制基因和癌基因的功能。此外，由于 Dicer 或 miRNA 加工所需的其他酶的丧失，导致 miRNA 活性整体降低，导致致瘤潜力增强，反映了 miRNA 在介导肿瘤抑制功能中的总体作用。我们的初步研究和其他小组的报告已将一部分 miRNA 与 PDAC 联系起来，基于：1）它们在胰腺细胞系和/或临床样本中的差异表达和/或 2）它们与病因相关的信号通路（如 K-Ras、p16 和 p53）的相互作用。因此，miRNA可以作为早期检测、诊断和/或预后的有用生物标志物，增进我们对肿瘤发生分子机制的理解，并作为新的治疗靶点。基于这些观察，我们的总体假设是，miRNA 在 PDAC 的起始和进展中发挥着至关重要的作用，并且与当前治疗药物和此类新型调节 RNA 的合成调节剂的组合治疗可能提供有效的策略来提高患者对治疗的反应。我们已经建立了几种转基因鼠品系，它们在 K-ras 和/或 p16 基因（PDAC 中最常见的突变基因）中携带条件突变，并且我们建议对 miRNA 进行功能分析，旨在评估： 1) 通过将条件性功能丧失的dicer1floxed/floxed 动物与携带 K-ras 突变等位基因的易患癌症的动物杂交，整体 miRNA 活性降低对疾病进展的影响 和/或p16基因。 2) 通过操纵小鼠和人类胰腺癌细胞系中 miRNA 的表达/活性水平，单个 miRNA 对体外胰腺肿瘤发生的贡献。公共健康相关性：胰腺导管腺癌 (PDAC) 是一种致命的恶性肿瘤，死亡率几乎等于发病率，但尚无令人满意的治疗方法。新的证据表明 microRNA 在癌症生物学中发挥着关键作用。我们假设当前化学毒性化合物和此类新型调节RNA的合成调节剂的组合疗法可能提供有效策略来提高患者对治疗的反应。在本提案中，我们将研究 microRNA 对 PDAC 的病因学贡献，并对其潜在的治疗应用进行初步评估。