1H MRI based nanosensors for imaging tumor oxygenation

描述(申请人提供)：肿瘤缺氧似乎与肿瘤增殖、恶性进展和治疗抵抗密切相关，因此它已成为肿瘤生理学和癌症治疗的中心问题。定量测量肿瘤氧合的能力对肿瘤的诊断和预后有重要价值。这项研究的总体目标是开发基于HMDSO的纳米乳剂作为基于质子磁共振成像的PO2报告纳米探针，并使用它们来探索联合化疗对肿瘤微环境的反应。这一创新的概念适用于快速临床翻译。具体目的1.(1-6个月)PO2纳米探针的合成与表征：在1-6个月内，将用超声乳化方法合成HMDSO纳米乳液作为PO2纳米探针，并用动态光散射进行表征。一种聚乙二醇衍生物表面活性剂将被用来增加血池保留时间，以使纳米探针渗入肿瘤。具体目标2.(7-12个月)测试纳米探针在血浆中随时间和不同pH条件下的稳定性，并获得随温度变化的pO2校准曲线：接下来，将测试合成的纳米乳液在各种pH条件下的稳定性。通过测量充入不同氧气水平气体的样品的自旋-晶格驰豫速率，可以得到生理范围内不同温度下的PO2校准曲线。具体目的3.(72只小鼠，13-20个月)将HMDSO纳米探针静脉注射到荷人前列腺癌(PC3)和乳腺癌(MCF7)的裸鼠体内，并通过核磁共振(MRI)测量肿瘤的摄取和清除：获得校准曲线后，将通过1H磁共振波谱研究不同颗粒尺寸的纳米探针的肿瘤摄取和清除，以确定在两种人肿瘤移植瘤中具有最佳摄取和时间过程的粒子。尼罗红染色也将评估体内的微观分布。具体目的4.(48只小鼠，21-24个月)检测GAS干预和血管靶向剂CA4P对肿瘤氧合的调节，并评价联合化疗对人前列腺癌(PC3)和乳腺癌(MCF7)裸鼠移植瘤的疗效：最后，将利用pO2纳米探针研究两种人前列腺癌(PC3)和乳腺癌(MCF7)裸鼠移植瘤的肿瘤氧动力学和对高氧的反应。由节律环磷酰胺组成的联合化疗的效果将被研究对肿瘤氧合参数，如基线pO2，hf5和对高氧的反应，以确定与长期结果相关的早期变化。使用方差分析对不同的治疗组和对照组进行统计比较。 与公共卫生相关：大多数组织需要氧气才能有效运作，低氧会导致快速的细胞功能障碍和损害。这项应用旨在开发一种使用纳米探针测量组织氧水平的新方法，该方法易于移植到临床上。虽然我们研究的是肿瘤，但这里开发的技术在各种疾病状态下都有潜在的应用，也可以应用于研究组织的基本生理学和氧气消耗。

DESCRIPTION (provided by applicant): Tumor hypoxia appears to be strongly associated with tumor propagation, malignant progression, and resistance to therapy and it has thus become a central issue in tumor physiology and cancer treatment. The ability to quantitatively measure tumor oxygenation could be of great value to cancer diagnosis and prognosis. The overall objective of the proposed research is to develop HMDSO based nanoemulsions as a proton magnetic resonance imaging based pO2 reporter nanoprobes and to use them to explore the tumor microenviromental response to combination chemotherapy. This innovative concept is suitable for rapid clinical translation. Specific Aim 1. (months 1-6) To synthesize and characterize pO2 nanoprobes: In months 1-6, HMDSO nanoemulsions will be synthesized for use as pO2 nanoprobes by ultrasonic emulsification method and characterized by dynamic light scattering. A polyethylene glycol derivative surfactant will be used to increase blood pool retention time for extravasation of the nanoprobes into tumors. Specific Aim 2. (months 7-12) Test nanoprobe stability in plasma over time and under variable pH conditions and obtain pO2 calibration curve as a function of temperature: Next, the stability of the synthesized nanoemulsions will be tested in a variety of pH conditions. pO2 calibration curves will be obtained for different temperatures in the physiologically relevant range by measurement of spin-lattice relaxation rates for samples bubbled with gases with different O2 levels. Specific Aim 3. (72 mice, months 13-20) To deliver HMDSO nanoprobes intravenously to nude mice bearing human prostate (PC3) and breast (MCF7) tumor xenografts and measure tumor uptake and clearance by MRI: Having obtained calibration curves, tumor uptake and clearance of nanoprobes will be studied by 1H magnetic resonance spectroscopy for different particle sizes to identify particles with optimal uptake and time course in two human tumor xenografts implanted in nude mice. In vivo microdistribution will also be assessed by Nile red staining. Specific aim 4. (48 mice, months 21-24) To detect the modulation of tumor oxygenation by gas intervention and vascular targeting agent CA4P and assess the efficacy of combination chemotherapy in human prostate (PC3) and breast (MCF7) tumor xenografts in mice: Finally, the pO2 nanoprobes will then be used to study tumor oxygen dynamics and response to hyperoxia in two human tumor xenografts implanted in nude mice. Effect of combination chemotherapy consisting of metronomic cyclophosphamide and will be studied on tumor oxygenation parameters such as baseline pO2, HF5 and response to hyperoxia with the view to identifying early changes that correlate with long- term outcome. Different treatment groups will be statistically compared to controls using ANOVA. PUBLIC HEALTH RELEVANCE: Oxygen is required for efficient function by most tissues and hypoxia leads to rapid cellular dysfunction and damage. This application aims to develop a novel method for measuring tissue oxygen levels using nanoprobes, which can be easily translated to the clinic. Although we study tumors, the technique developed here has potential applications in a wide range of diseased states and can be applied to study basic physiology and oxygen consumption in tissue as well.