Finding NEMO's Switchable MRI Signal Using Microfluidic Tumor Models

项目摘要 误诊在接受乳腺癌筛查的乳腺组织致密的年轻女性中很普遍， 从而导致错过癌症、不必要的后续测试、焦虑和医疗费用。与乳房X光检查相比， 磁共振成像（MRI）检测到更多的乳腺癌，但仍然存在高假阳性率 由于所使用的常规造影剂，例如，钆（Gd）螯合物。我们的长期目标是发展 用于乳腺癌早期检测的新型安全造影剂，可减少假阳性和假阴性 乳房MRI Gd螯合物的不良性能是由于它们缺乏靶向和恒定的MRI信号。 通过保持活性，Gd螯合物在正常组织中产生高背景信号，并突出良性和非良性组织。 和恶性肿瘤。为了实现我们的长期目标，我们开发了纳米封装锰 氧化物（NEMO）颗粒，其将为Gd螯合物提供上级替代物。我们的初步数据显示， NEMO颗粒特异性是通过向糖基化不足的粘蛋白-1添加肽靶向来实现的， 只在乳腺癌细胞上过度表达。NEMO颗粒提供独特的pH可切换信号， 仅在酸性肿瘤细胞内体（pH 5）中内化后被激活。在pH为 血液（pH 7.4）或肿瘤细胞外空间（pH 6.5）。我们的体内研究表明NEMO颗粒 在小鼠中是安全耐受的，并且表现出比Gd-螯合物更强的信号。目前，没有高通量方法 用于测试新的MRI造影剂，预测体内性能。本项目的目标是 开发一种创新的便携式仪器，以评估灵敏度、特异性和安全性 使用3D微流体肿瘤模型的MRI和光学成像的NEMO颗粒与Gd螯合物的比较。我们的中央 假设NEMO颗粒将引起低毒性，特异性标记乳腺癌细胞， 在3D微流体肿瘤模型和乳腺癌小鼠中与Gd螯合物的MRI对比度比较。我们 将以两个目的检验假设：1）评价3D微流体中NEMO颗粒与Gd螯合物MRI对比 肿瘤模型和小鼠。2)评价NEMO颗粒在3D微流体肿瘤模型中的毒性和分布 和老鼠。这个项目是创新的，因为NEMO颗粒独特地响应于内体pH， 仅在乳腺癌细胞内进行对比，以提供简单的二进制读数（良性“OFF”，恶性“ON”）。 先前开发的pH敏感型MRI造影剂对酸性细胞外间隙的反应类似 在良性和恶性肿瘤中。我们还将创建一种新的设备，使3D微流体肿瘤的MRI 模特第一次这项研究是有意义的，因为我们将证明NEMO粒子 与Gd螯合物相比，具有上级特异性、信号强度和安全性。这一R15奖项将提供削减- 在西弗吉尼亚大学对本科生进行纳米材料和医学成像研究的边缘培训。 在3年内，6名攻读工程或生物医学科学学位的本科生将被招募，培养， 并进行评估。这项工作将导致NEMO颗粒的进一步临床前开发和临床试验。

PROJECT SUMMARY Misdiagnosis is prevalent in younger women with dense breast tissue receiving breast cancer screening, resulting in missed cancers, needless follow-up testing, anxiety, and medical costs. Compared to mammography, magnetic resonance imaging (MRI) detects more breast cancers but still suffers from high false positive rates due to the conventional contrast agents used, e.g., gadolinium (Gd)-chelates. Our long-term goal is to develop novel, safe contrast agents for early detection of breast cancer that reduce the false positives and false negatives of breast MRI. The poor performance of Gd-chelates results from their lack of targeting and constant MRI signal. By remaining active, Gd-chelates produce high background signal in normal tissues and highlight both benign and malignant tumors. To address our long-term goal, we have developed Nano-, Encapsulated Manganese Oxide (NEMO) particles that will provide superior replacements for Gd-chelates. Our preliminary data shows that NEMO particle specificity is achieved by adding peptide targeting to underglycosylated mucin-1, which is overexpressed exclusively on breast cancer cells. NEMO particles provide a unique pH-switchable signal that is only activated upon internalization in acidic tumor cell endosomes (pH 5). No MRI signal is produced at pH of the blood (pH 7.4) or tumor extracellular space (pH 6.5). Our in vivo studies demonstrate that NEMO particles are safely tolerated in mice and exhibit a stronger signal than Gd-chelates. Currently, no high throughput method exists for testing new MRI contrast agents that predicts in vivo performance. The goals of the current project are to develop an innovative portable apparatus to enable evaluation of the sensitivity, specificity, and safety profile of NEMO particles vs. Gd-chelates using MRI and optical imaging of 3D microfluidic tumor models. Our central hypothesis is that NEMO particles will elicit low toxicity, specifically label breast cancer cells, and yield higher MRI contrast compared to Gd-chelates in 3D microfluidic tumor models and in mice with breast cancer. Our hypothesis will be tested with two aims: 1) Evaluate NEMO particle vs. Gd-chelate MRI contrast in 3D microfluidic tumor models and mice. 2) Evaluate toxicity and distribution of NEMO particles in 3D microfluidic tumor models and mice. This project is innovative because NEMO particles uniquely respond to endosomal pH to generate contrast only inside breast cancer cells to provide a simple binary readout (benign “OFF”, malignancy “ON”). Previously developed pH-sensitive MRI contrast agents respond to the acidic extracellular space, which is similar in benign and malignant tumors. We will also create a novel apparatus to enable MRI of 3D microfluidic tumor models for the first time. The proposed research is significant because we will demonstrate that NEMO particles have superior specificity, signal strength, and safety compared to Gd-chelates. This R15 award will offer cutting- edge training to undergraduates in nanomaterials and medical imaging research at West Virginia University. Over 3 years, 6 undergraduates pursuing engineering or biomedical sciences degrees will be recruited, trained, and assessed. This work will lead to further preclinical development and clinical trials of NEMO particles.