Fluorescence lifetime tomography of tumor physiology in small animals

描述(申请人提供)：这项提议的目标是发展一种光学成像系统，用于使用荧光寿命对比度进行纵向、高通量的小动物癌症成像。我们将具体提出并验证一种新的基于时间域(TD)寿命的断层扫描技术，用于对两个重要且相关的现象进行全身成像，即肿瘤转移和血管生成。我们将首先使用可见光谱(450 nm-650 nm)中的荧光蛋白(FP)对转移的整个动物进行成像。FPS的寿命成像将应用于跟踪人类乳腺癌小动物模型的转移。这将使对活体小鼠转移灶的纵向量化比目前使用其他非侵入性技术可能的早期阶段更早。接下来，我们将使用具有不同寿命的近红外(NIR)(650 nm-850 nm)荧光团来研究治疗过程中的血管生成和药物输送。光学成像可以实现对整个肿瘤体积的快速、深层组织(&gt；1厘米)成像，分辨率为毫米级，这可以在治疗干预下对肿瘤生理进行全球定量读数。光学成像还提供了一个独特的机会，可以使用具有不同寿命的多个荧光团同时跟踪肿瘤体积内的多个过程(寿命“多路传输”)。我们将验证生命周期多路传输技术，以同时跟踪血管生成和向肿瘤的药物输送。为了实现这一点，我们将使用针对血管系统的近红外荧光团和第二个标记为赫赛汀的具有不同寿命的近红外荧光团。赫赛汀是一种针对人表皮生长因子受体2(HER2/neu)的抗血管生成和治疗药物，HER2/neu在人类乳腺癌中过度表达。此外，组织光学对比度的近红外光谱将揭示治疗后肿瘤血容量和氧合的变化，表达FP的癌细胞将揭示肿瘤的生长。通过能够同时监测整个肿瘤体积中的多个生理标记物，这项技术将为Herceptin治疗期间血管生成和药物输送之间的相互作用提供新的见解，并将使开发中的抗癌药物得到验证和优化。 公共卫生相关性：使用新的分子靶向癌症诊断和治疗方法进行早期发现和预防是减少癌症死亡的关键战略。这项提议将推进一种非侵入性的、临床前的、利用终身对比度的时域荧光系统，这将加速癌症疗法的发现。

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.