In Vivo Bioimaging Model to Study Inducible Drug Resistance in Cancer

研究癌症诱导耐药性的体内生物成像模型

• 批准号: 8250403
• 负责人: SUSAN E KANE
• 金额: $ 33.41万
• 依托单位: BECKMAN RESEARCH INSTITUTE/CITY OF HOPE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2014-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8250403
• 关键词: ABCB1 gene; Acute; Affect; Animal Model; Animals; Antineoplastic Agents; Biological Models; Breast; Breast Cancer Model; Cancer Patient; Chemicals; Cis-Acting Sequence; Clinical; Development; Drug Kinetics; Drug resistance; Elements; Engineering; Evaluation; Event; Firefly Luciferases; Gene Expression; Genes; Genetic Crosses; Genetic Recombination; Genomics; Health; Human; Image; Imaging technology; In Situ; Intestines; Kidney; Kinetics; Knock-in Mouse; Knowledge; Ligands; Link; Liver; Longitudinal Studies; Malignant Neoplasms; Mammary Gland Parenchyma; Measurement; Measures; Mediating; Messenger RNA; Modeling; Monitor; Multi-Drug Resistance; Mus; Normal tissue morphology; Organ; Outcome; Pharmaceutical Preparations; Pharmacotherapy; Physiological; Regulation; Reporter; Reporter Genes; Research; Resistance; Role; Signal Transduction; Stimulus; System; Technology; Time; Tissues; Trans-Activators; Transcriptional Regulation; Transgenic Model; Translations; Work; Xenobiotics; bioimaging; cancer therapy; chemotherapy; homologous recombination; in vivo; insight; mRNA Stability; malignant breast neoplasm; molecular imaging; novel; novel strategies; overexpression; recombinase; response; tool; tumor; tumor progression; tumorigenesis; uptake

DESCRIPTION (provided by applicant): Transcriptional regulation represents the major mechanism of controlling gene expression, yet we have little direct knowledge of how genes are regulated in the whole body, due largely to an inability to observe and measure changes in gene expression under real physiological conditions and in real time. For similar reasons, it has not been possible to study directly the effects of given cancer therapies on their target(s), if mediated at the transcriptional level. However, the recent revolution in molecular imaging has yielded novel tools for performing noninvasive, in vivo imaging of gene expression. A biologically relevant application of imaging technology is to target, by homologous recombination, a reporter gene into the genomic locus of an endogenous gene so that the regulated expression of that gene can be monitored non-invasively, in real time, and in response to internal and external signals. We have established such a system using the mouse mdr1a locus as a proof of principle and as a biologically important gene. Multidrug resistance (MDR) remains a serious impediment to curative chemotherapy in cancer patients. One mechanism of MDR is the enhanced expression of the MDR1 gene. MDR1 overexpression has been associated with drug resistance in many human cancers, but its contribution to clinical outcomes remains unresolved. Systematic longitudinal studies to determine MDR1's role in resistance are difficult, if not impossible, to perform in humans and an adequate animal model to study such questions has not previously been available. The role of MDR1 in drug pharmacokinetics is well established, but the regulation of MDR1 in normal organs involved in drug uptake and clearance is poorly understood. In our preliminary studies: 1) We have engineered mdr1a+/fLUC mice that have firefly luciferase (fLUC) targeted to the mdr1a gene's genomic locus in a way that makes in-frame expression of fLUC conditional on Cre-mediated recombination. 2) We have shown that expression of fLUC under the control of the endogenous mdr1a gene locus is a faithful in vivo reporter for mdr1a expression in the basal, steady state. 3) We have also demonstrated that fLUC can be used to monitor induction of mdr1a gene expression in response to xenobiotic stimuli. We now propose to use this non-invasive model system to study mdr1a gene expression in the in vivo setting. We will also extend the model to be able to study both the cis-acting and trans-acting factors that control mdr1a gene expression at the transcriptional, post-transcriptional and translational level. Aim 1 is to determine if mdr1a is induced in normal organs in a tissue-specific fashion. Aim 2 is to determine if mdr1a is induced during breast cancer progression and/or treatment. Aim 3 is to determine if specifi trans-acting and cis-acting factors are required for mdr1a induction in specific tissues. PUBLIC HEALTH RELEVANCE: Multidrug resistance remains a serious impediment to curative chemotherapy in cancer patients. One mechanism of multidrug resistance is the enhanced expression of the mdr1 gene. Mdr1 overexpression has been associated with drug resistance in many human cancers, but its contribution to clinical drug resistance remains unresolved. Our work makes it possible to study the regulation of mdr1 in situ, in real time, and in response to developmental, physiological, or environmental signals. Project results will provide greater insights into mechanisms by which mdr1 is turned on during cancer progression and drug treatment, thus potentially leading to novel approaches to avoiding such events in humans.

描述（申请人提供）：转录调控是控制基因表达的主要机制，但我们对基因在整个机体中如何调控的直接了解很少，很大程度上是由于无法观察和测量真实生理条件下基因表达的变化。条件和实时。出于类似的原因，如果在转录水平上介导，则不可能直接研究给定癌症疗法对其靶点的影响。然而，最近分子成像的革命产生了用于执行非侵入性体内基因表达成像的新工具。成像技术的生物学相关应用是通过同源重组将报告基因靶向内源基因的基因组位点，以便可以非侵入性地实时监测该基因的调节表达，并响应内部和外部信号。我们使用小鼠 mdr1a 基因座作为原理证明和生物学上重要的基因建立了这样一个系统。多药耐药性（MDR）仍然是癌症患者治疗性化疗的严重障碍。 MDR 的机制之一是 MDR1 基因的表达增强。 MDR1 过度表达与许多人类癌症的耐药性有关，但其对临床结果的贡献仍未解决。在人类身上进行系统性纵向研究来确定 MDR1 在耐药性中的作用即使不是不可能，也是很困难的，而且之前还没有足够的动物模型来研究此类问题。 MDR1 在药物药代动力学中的作用已得到充分证实，但 MDR1 在参与药物摄取和清除的正常器官中的调节却知之甚少。在我们的初步研究中：1) 我们设计了 mdr1a+/fLUC 小鼠，将萤火虫荧光素酶 (fLUC) 靶向 mdr1a 基因的基因组位点，使 fLUC 的框内表达以 Cre 介导的重组为条件。 2）我们已经证明，在内源性 mdr1a 基因位点控制下的 fLUC 表达是基础稳定状态下 mdr1a 表达的忠实体内报告者。 3）我们还证明，fLUC 可用于监测 mdr1a 基因表达对外源刺激的反应。我们现在建议使用这种非侵入性模型系统来研究体内 mdr1a 基因表达。我们还将扩展该模型，使其能够研究在转录、转录后和翻译水平上控制 mdr1a 基因表达的顺式作用和反式作用因子。目标 1 是确定 mdr1a 是否在正常器官中以组织特异性方式诱导。目标 2 是确定在乳腺癌进展和/或治疗过程中是否会诱导 mdr1a。目标 3 是确定特定组织中 mdr1a 诱导是否需要特定的反式作用和顺式作用因子。公共卫生相关性：多重耐药性仍然是癌症患者治疗性化疗的严重障碍。多药耐药性的机制之一是 mdr1 基因的表达增强。 Mdr1 过度表达与许多人类癌症的耐药性有关，但其对临床耐药性的贡献仍未解决。我们的工作使得实时原位研究 mdr1 对发育、生理或环境信号的调节成为可能。项目结果将提供对 mdr1 在癌症进展和药物治疗过程中开启机制的更深入了解，从而有可能带来避免人类发生此类事件的新方法。