Fluorescence lifetime tomography of tumor physiology in small animals

描述（由申请人提供）：本提案的目标是推进一种利用荧光寿命对比进行纵向、高通量小动物癌症成像的光学成像系统。我们将特别提出并验证一种新的时域（TD）基于寿命的断层扫描技术，用于两种重要的相关现象的全身成像，即肿瘤转移和血管生成。我们将首先使用荧光蛋白（FPs）在可见光谱（450nm - 650nm）中实现转移的全动物成像。FPs的终生成像将被应用于人类乳腺癌小动物模型的转移跟踪。与目前其他非侵入性技术相比，这将允许在早期阶段对活体小鼠的转移灶进行纵向量化。接下来，我们将使用具有不同寿命的近红外（NIR） （650nm - 850nm）荧光团来研究治疗期间的血管生成和药物递送。光学成像可以实现整个肿瘤体积的快速、深部组织（bbb1cm）成像，分辨率为mm级，可以在治疗干预下实现肿瘤生理的全局定量读数。光学成像还允许使用具有不同寿命的多个荧光团（寿命“多路复用”）同时跟踪肿瘤体积内的多个过程的独特机会。我们将验证生命周期多路复用，以同时跟踪血管生成和药物输送到肿瘤。为了实现这一目标，我们将使用一个针对血管系统的近红外荧光团和第二个具有不同寿命的近红外荧光团，该荧光团被标记为赫赛汀。赫赛汀是一种抗血管生成和治疗药物，靶向人表皮生长因子受体2 (HER2/neu)，该受体在人乳腺癌中过度表达。此外，近红外光谱的内在组织光学对比可以揭示肿瘤血容量和氧合的变化，表达FP的癌细胞可以揭示肿瘤的生长情况。通过在整个肿瘤体积中同时监测多种生理标志物，该技术将为赫赛汀治疗期间血管生成和药物传递之间的相互作用提供新的见解，并将允许验证和优化发展中的癌症药物。

DESCRIPTION (provided by applicant): The goal of this proposal is to advance an optical imaging system for longitudinal, high throughput small animal cancer imaging using fluorescence lifetime contrast. We will specifically advance and validate a novel time domain (TD) lifetime- based tomography technique for whole-body imaging of two important and related phenomena, namely tumor metastasis and angiogenesis. We will first enable whole animal imaging of metastasis using fluorescent proteins (FPs) in the visible spectrum (450nm - 650nm). Lifetime imaging of FPs will be applied to track metastasis in a small animal model of human breast cancer. This will allow longitudinal quantification of metastatic foci in living mice at earlier stages than currently possible with other non- invasive techniques. We will next employ near infra-red (NIR) (650nm - 850nm) fluorophores with distinct lifetimes to study angiogenesis and drug delivery during therapy. Optical imaging can enable rapid, deep tissue (> 1 cm) imaging of the entire tumor volume with mm-scale resolution, which can allow global quantitative readouts of tumor physiology under therapeutic intervention. Optical imaging also allows a unique opportunity for simultaneously tracking multiple processes within the tumor volume using multiple fluorophores with distinct lifetimes (lifetime "multiplexing"). We will validate lifetime multiplexing to track angiogenesis and drug delivery to tumors simultaneously. In order to achieve this, we will use a NIR fluorophore that targets vasculature and a second NIR fluorophore with distinct lifetime that is tagged to herceptin. Herceptin is an anti-angiogenic and therapeutic agent that targets the human epidermal growth factor receptor 2 (HER2/neu), which is over-expressed in human breast cancers. Additionally, NIR spectroscopy of intrinsic tissue optical contrast will reveal changes in tumor blood volume and oxygenation due to therapy, and FP expressing cancer cells will reveal tumor growth. By enabling simultaneous monitoring of multiple physiological markers in the entire volume of tumor, this technology will provide new insights into the interplay between angiogenesis and drug delivery during herceptin treatment, and will allow the validation and optimization of developmental cancer drugs. PUBLIC HEALTH RELEVANCE: Early detection and prevention using novel molecularly targeted cancer diagnostics and therapeutics is a key strategy to reduce cancer deaths. This proposal will advance a non-invasive, pre-clinical time domain fluorescence system exploiting lifetime contrast that will accelerate the discovery of cancer therapeutics.