Hyperspectral Microendscopy to Monitor VEGF During Pancreatic Cancer Therapy

描述（由申请人提供）：胰腺癌（PanCa）是一种毁灭性疾病，在所有恶性肿瘤中5年生存率最低（<5%）；因此，迫切需要改进治疗方案。胰腺癌细胞和其他类型的癌细胞在治疗过程中上调特定基因的表达，促进肿瘤细胞的增殖和存活。例如，癌细胞可以增加细胞信号因子的产生，如细胞因子生长因子及其受体。血管内皮生长因子（VEGF）是众多细胞因子在肿瘤存活和转移中发挥作用的一个例证。Hasan小组和其他人已经表明，在对化疗、放疗和光动力疗法（PDT）等亚治愈性细胞毒性疗法的反应中，癌细胞上调了VEGF的表达。这种肿瘤反应常常导致疾病复发和转移增加，这与治疗的目标是矛盾的。在研究减轻这种影响的策略时，Hasan小组发现，在PDT后的短时间内，分泌的VEGF水平升高。这一结果强调了在癌症治疗期间开发在线监测细胞因子的工具的重要性。该研究的总体目标是在PDT和抗VEGF联合治疗期间，捕获原位小鼠PanCa肿瘤模型中肿瘤VEGF表达的时空动态。本研究还将研究使用新开发的纳米颗粒靶向细胞内VEGF的增强治疗效果。我们的首要目标是构建一种微创、定量的分子成像系统。一种柔性的、直径为亚毫米的光纤成像束将用于胰腺肿瘤的原位成像。该探针将与高光谱荧光检测系统耦合，以方便严格量化分泌的VEGF水平的相对变化。也就是说，图像的每个像素将包含一个荧光发射光谱，每个像素将被分析以从组织自身荧光中分离出抗VEGF单克隆抗体-荧光团共轭荧光（我们将用于可视化VEGF的显像剂）。提出的设计将使纵向研究中频繁成像。基于记录的VEGF表达和分泌动态，我们将实施定时递送和最佳剂量的抗VEGF治疗药物靶向适当的组织室（使用纳米结构靶向细胞内VEGF和游离阿瓦斯汀靶向细胞外VEGF），以最佳地阻断VEGF活性。这项工作将为图像引导的PanCa治疗改善治疗结果提供潜力，并将研究利用纳米技术靶向和中和细胞内细胞因子生长因子池改善治疗结果的机制。

DESCRIPTION (provided by applicant): Pancreatic cancer (PanCa) is a devastating disease with the lowest 5-year survival rate of all malignancies (<5%); therefore, there is a desperate need for improved treatment regimens. Pancreatic cancer cells and other cancer cell types up-regulate their expression of specific genes during therapy to promote tumor cell proliferation and survival. For example, cancer cells can increase production of cellular signaling factors, such as cytokine growth factors and their receptors. Vascular endothelial growth factor (VEGF) exemplifies the multitude of cytokines that play a role in tumor survival and metastasis. The Hasan group and others have shown that VEGF expression is up-regulated by cancer cells in response to subcurative cytotoxic therapies, such as chemotherapy, radiotherapy and photodynamic therapy (PDT). This tumor response often leads to disease recurrence and increased metastasis, paradoxical to the goals of therapy. During investigation for strategies to mitigate this effect, the Hasan group has found that secreted VEGF levels are elevated during a short time window following PDT. This result underscores the importance for developing tools to monitor cytokines online during cancer therapy. The overall goal of the proposed research is to capture the spatiotemporal dynamics of tumoral VEGF expression in an orthotopic, murine PanCa tumor model during combined PDT and anti-VEGF therapy. This study will also investigate the enhanced treatment outocome found using a newly developed nanoparticle to target the intracellular pool of VEGF. Our first aim is to construct a minimally invasive, quantitative molecular imaging system. A flexible, submillimeter-diameter fiber-optic imaging bundle will be used to access and image pancreatic tumors in situ. This probe will be coupled to a hyperspectral fluorescence detection system to facilitate rigorous quantification of relative changes in secreted VEGF levels. That is, each pixel of the image will contain a fluorescence emission spectrum and each pixel will be analyzed to isolate the anti-VEGF monoclonal antibody-fluorophore conjugate fluorescence (the imaging agent we will employ to visualize VEGF) from the tissue autofluorescence. The proposed design will enable frequent imaging during longitudinal studies. Based on the recorded VEGF expression and secretion dynamics, we will implement timed delivery and optimal dosing of an anti-VEGF therapeutic agent targeted to the appropriate tissue compartments (using the nanoconstruct to target intracellular VEGF and free Avastin to target extracellular VEGF) to optimally block VEGF activity. This work will ases the potential for image-guided PanCa therapy to improve treatment outcomes, and will investigate the mechanism of impoved therapeutic outcome using nanotechnology to target and neutralize intracellular pools of cytokine growth factors. PUBLIC HEALTH RELEVANCE: Pancreatic cancer is a devastating disease with one of the worst prognoses in medicine. This project aims to improve pancreatic cancer treatment by addressing the spatiotemporal dynamics of key molecular mediators of tumor survival and proliferation. This project integrates new image-guidance and nanotechnology platforms to deliver therapeutic agents at the "right time" and to the "right place" for optimal inhibition of cancer cell survival and metastasis.