Non-invasive molecular MR spectroscopic imaging of histone deacetylase activity

描述（由申请人提供）：对癌症潜在机制的深入了解正在导致针对个体患者量身定制的新型靶向治疗的发展。然而，对这些疗法的反应往往导致肿瘤停滞。因此，生物学相关的药物剂量和对治疗的早期反应是使用间接或侵入性指标确定的。因此，迫切需要一种评估药物递送和靶部位分子反应的非侵入性方法。我们的长期目标是开发和实施基于非侵入性磁共振（MR）的分子成像方法，可以检测新型靶向癌症治疗的作用和反应。本应用的目的是临床前测试和实现一种直接的、无创的、19F MR光谱标记组蛋白去乙酰化酶（HDAC）活性，作为体内对HDAC抑制剂（HDAC）分子反应的特定指标。第二个目标是确定与HDAC抑制相关的下游代谢生物标志物。我们提议测试氟化赖氨酸衍生物Boc-Lys-TFA-OH （BIT）。我们已经证实BLT在体外被HDAC切割。从细胞提取物的MR光谱（MRS）研究中，我们还确定了HDAC治疗后细胞内BLT水平显著升高，并与HDAC抑制相关。在处理过的细胞提取物中，磷胆碱（PC）和总胆碱（tCho）水平也较高。因此，我们认为较高的细胞BLT水平和较高的tCho水平可以作为HDAC抑制的分子标记。为了在体内实现这一目标，我们提出：证实BLT作为HDAC抑制的MRS药效学标志物。我们将使用灌注的活细胞来模拟细胞内和细胞外BLT信号无法区分的体内情况。BLT水平将通过高分辨率MRS监测，并与对照和HDAC处理细胞中的HDAC活性相关。具体目标2。利用磁共振波谱成像技术监测HDAC在肿瘤体内的抑制作用。我们将使用局部19F光谱成像来监测BLT水平，1H光谱成像来测量对照组和治疗组肿瘤的tCho水平。MR数据将与HDAC活性、下游信号和肿瘤大小相关。未来将这种方法应用于临床，将允许对hdaci治疗进行无创纵向定位监测。通过告知药物输送和分子对治疗的反应，无创和在目标部位，这项技术因此有望改善病人的护理。的相关性。hdac是一种新型抗癌药物，目前正处于临床试验阶段，具有良好的效果。然而，适当的药物剂量和早期反应往往难以评估。这项工作的目标是开发一种无创的基于核磁共振成像的方法来检测靶部位对HDACIs的反应。因此，将这种方法引入临床使用将转化为改善患者护理。

DESCRIPTION (provided by applicant): Greater understanding of the underlying mechanisms of cancer is leading to development of novel targeted therapies tailored to individual patients. However, response to these therapies often results in tumor stasis. Consequently, the biologically relevant drug dose and early response to treatment are determined using indirect or invasive indicators. A noninvasive method of assessing drug delivery and molecular response at the target site is therefore critically needed. Our long-term goal is to develop and implement noninvasive magnetic resonance (MR)-based molecular imaging methods that can detect the action of and response to novel targeted cancer treatments. The goal of this application is to pre-clinically test and implement a direct, noninvasive, 19F MR spectroscopic marker of histone deacetylase (HDAC) activity, as a specific indicator of molecular response to HDAC inhibitors (HDACIs) in vivo. A secondary goal is to identify downstream metabolic biomarkers associated with HDAC inhibition. We propose to test the fluorinated lysine derivative Boc-Lys-TFA-OH (BIT). We have confirmed that BLT is cleaved in vitro by HDAC. From MR spectroscopy (MRS) studies of cell extracts we have also determined that intracellular BLT levels are significantly higher following HDACI-treatment and correlate with HDAC inhibition. Phosphocholine (PC) and total choline (tCho) levels are also higher in treated cell extracts. We therefore suggest that higher cellular BLT levels together with higher tCho levels can serve as molecular markers of HDAC inhibition. To implement this in vivo we propose: Specific Aim 1. To confirm BLT as an MRS pharmacodynamic marker of HDAC inhibition. We will use perfused live cells to model the in vivo situation in which intracellular and extracellular BLT signals are indistinguishable. BLT levels will be monitored by high resolution MRS and correlated with HDAC activity in control and HDACI-treated cells. Specific Aim 2. To monitor HDAC inhibition in tumors in vivo using magnetic resonance spectroscopic imaging. We will use localized 19F spectroscopic imaging to monitor BLT levels and 1H spectroscopic imaging to measure tCho levels in control and treated tumors. The MR data will be correlated with HDAC activity, downstream signaling and tumor size. Future translation of this method to the clinic will allow for noninvasive longitudinal localized monitoring of HDACI-treatment. By informing on drug delivery and molecular response to treatment, noninvasively and at the target site, this technique therefore promises to improve patient care. Relevance. HDACIs are novel anti-cancer agents currently in clinical trials with promising results. However, appropriate drug dose and early response are often difficult to assess. The goal of this work is to develop a noninvasive MRS-based imaging method for detecting response to HDACIs at the target site. The introduction of this method into clinical use will therefore translate into improved patient care.