1H MRI based nanosensors for imaging tumor oxygenation

描述（由申请人提供）：肿瘤缺氧似乎与肿瘤增殖、恶性进展和对治疗的抗性密切相关，因此它已成为肿瘤生理学和癌症治疗中的中心问题。定量测量肿瘤氧合的能力对癌症诊断和预后具有重要价值。拟议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pO 2报告纳米探针，并使用它们来探索肿瘤微环境对联合化疗的反应。这一创新概念适用于快速临床翻译。具体目标1。（1-6个月）合成和表征pO 2纳米探针：在1-6个月，将通过超声乳化法合成HMDSO纳米乳液用作pO 2纳米探针，并通过动态光散射表征。聚乙二醇衍生物表面活性剂将用于增加纳米探针外渗到肿瘤中的血池保留时间。具体目标2。（7-12个月）测试纳米探针随时间推移和在可变pH条件下在血浆中的稳定性，并获得作为温度函数的pO 2校准曲线：接下来，将在各种pH条件下测试合成的纳米乳液的稳定性。将通过测量用不同O2水平的气体鼓泡的样品的自旋-晶格弛豫速率，获得生理相关范围内不同温度下的pO 2校准曲线。具体目标3。(72小鼠，13-20个月）为了将HMDSO纳米探针静脉内递送至携带人前列腺（PC 3）和乳腺（MCF 7）肿瘤异种移植物的裸鼠，并通过MRI测量肿瘤摄取和清除：获得校准曲线后，将通过1H磁共振光谱法研究不同粒径的纳米探针的肿瘤摄取和清除，以鉴定在两种人类肿瘤中具有最佳摄取和时间过程的颗粒。在裸鼠中植入的异种移植物。还将通过尼罗红染色评估体内微分布。具体目标4。(48小鼠，21-24个月）检测通过气体干预和血管靶向剂CA 4P对肿瘤氧合的调节，并评估联合化疗在小鼠中的人前列腺（PC 3）和乳腺（MCF 7）肿瘤异种移植物中的功效：最后，pO 2纳米探针将用于研究植入裸鼠中的两种人肿瘤异种移植物中的肿瘤氧动力学和对高氧的反应。将研究由节拍环磷酰胺组成的联合化疗对肿瘤氧合参数（如基线pO 2、HF 5和对高氧反应）的影响，以确定与长期结局相关的早期变化。将使用ANOVA对不同给药组与对照组进行统计学比较。 公共卫生相关性：大多数组织的有效功能都需要氧气，缺氧会导致快速的细胞功能障碍和损伤。该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，该方法可以很容易地应用于临床。虽然我们研究肿瘤，但这里开发的技术在广泛的疾病状态中具有潜在的应用，并且也可以应用于研究组织中的基本生理学和氧消耗。

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.