Exploiting Melanin Synthesis to Improve Tumor Detection with Multispectral Optoacoustic Tomography and Optical Guided Surgery

我们的目标是提高表达和分泌高水平蛋白酶的实体瘤的定位 内切酶蛋白酶降解细胞外基质和细胞基质，增加肿瘤增殖， 侵袭和转移。我们的研究将集中在用组织蛋白酶B和尿激酶检测肿瘤 纤溶酶原激活物是恶性肿瘤的蛋白酶生物标志物。但我们的技术可以检测到许多 因此，可以是用于检测许多类型的肿瘤的灵活平台技术。 为了实现我们的目标，我们建议开发一种新型的造影剂，这种造影剂可以被蛋白酶切割， 发生自发分解，最后自发形成真黑素或褐黑素。我们的对比 试剂由肽和黑色素组成，它们是天然的生物相容性材料。我们的自发 拆卸接头用于药物递送，使得这些接头也是生物相容的。所以我们的 造影剂具有很强的最终临床转化潜力。 我们建议使用我们的黑色素生成造影剂，以改善肿瘤定位与非侵入性 多光谱光声层析成像（MSOT），也称为光声成像。临床前MSOT可以 对小鼠肿瘤模型的整个躯干进行成像，并且临床MSOT已经用于对许多肿瘤类型进行成像 包括乳腺癌我们将开发和使用一种创新的动态MSOT成像协议， 肿瘤中黑色素的产生，这提高了蛋白酶活性肿瘤相对于正常组织的特异性。 我们还建议使用我们的黑色素生成造影剂，以改善手术过程中的肿瘤定位。 其他研究已经开发出荧光造影剂，其在具有高荧光强度的肿瘤中被捕获或激活。 蛋白酶活性然后，这些肿瘤可以在手术过程中可视化，此时肿瘤可以用 荧光成像仪器。我们的技术将导致黑色素在肿瘤中积累， 蛋白酶活性，导致肿瘤变黑。简单的目视检查，无需昂贵的 笨重的荧光成像仪器，可以识别黑色肿瘤对米色到红色 正常组织的背景。这些黑色肿瘤可以在手术中从体内切除。作为 长期目标，我们建议MSOT最终可用于定位蛋白酶活性肿瘤， 在手术过程中暴露的组织表面的距离为3cm，进一步改善了肿瘤的手术切除。 为了达到我们的目的，我们将合成每种造影剂，证明与特定的 酶导致黑色素的合成，并进行Michaelis-Menten酶动力学研究以验证 酶活性检测。对于目标1，我们将进行体内MSOT研究以检测蛋白酶活性。 人类肿瘤的小鼠模型。对于目标2，我们将用小鼠肿瘤模型模拟光学引导手术 来检测黑色素高度积累的黑色肿瘤。我们的交付成果是追求临床 在临床MSOT检查和临床手术期间转换我们的造影剂。

Our goal is to improve the localization of solid tumors that express and secrete high levels of protease enzymes. Proteases degrade the extracellular matrix and cellular stroma, increasing tumor proliferation, invasion, and metastasis. Our research will focus on the detection of tumors with cathepsin B and urokinase Plasminogen Activator, which are protease biomarkers of malignant tumors. Yet our technology can detect many types of proteases, and therefore can be a flexible platform technology for detecting many types of tumors. To meet our goal, we propose to develop a new type of contrast agent that is cleaved by a protease, then undergoes spontaneous disassembly, and finally spontaneously forms eumelanin or pheomelanin. Our contrast agents consist of peptides and melanins that are natural, biocompatible materials. Our spontaneous disassembling linkers are used for drug delivery, so that these linkers are also biocompatible. Therefore, our contrast agents have strong potential for eventual clinical translation. We propose to use our melanin-generating contrast agents to improve tumor localization with noninvasive Multispectral Optoacoustic Tomography (MSOT), also known as photoacoustic imaging. Pre-clinical MSOT can image an entire torso of mouse tumor models, and clinical MSOT has been used to image many tumor types including breast cancer. We will develop and use an innovative dynamic MSOT imaging protocol that will monitor the generation of melanins in tumors, which improves the specificity of protease-active tumors vs. normal tissues. We also propose to use our melanin-generating contrast agents to improve tumor localization during surgery. Other research has developed fluorescent contrast agents that are trapped or activated in tumors with high protease activity. These tumors can then be visualized during surgery, when the tumors can be imaged with fluorescence imaging instrumentation. Our technology will cause melanins to accumulate in tumors with high protease activity, causing the tumors to become black. Simple visual inspection, without expensive and cumbersome fluorescence imaging instrumentation, can identify the black tumors against the beige-to-red background of normal tissues. These black tumors can then be excised from the body during surgery. As a longer-term goal, we propose that MSOT could eventually be used to localize protease-active tumors as deep as 3 cm from tissue surfaces that are exposed during surgery, further improving surgical resection of tumors. To meet our objectives, we will synthesize each contrast agent, demonstrate that cleavage with a specific enzyme results in synthesis of a melanin, and perform Michaelis-Menten enzyme kinetics studies to validate the detection of enzyme activity. For Aim 1, we will perform in vivo MSOT studies to detect protease activities in mouse models of human tumors. For Aim 2, we will simulate optical guided surgery with mouse tumor models to detect black tumors that have high melanin accumulation. Our deliverable is a foundation for pursuing clinical translation of our contrast agents for clinical MSOT exams and during clinical surgery.