Development of aptamer-based detection and therapy strategies for ovarian cancer

描述(申请人提供)：对卵巢癌更好的早期发现的需求持续存在。目前，卵巢癌的检测部分依赖于抗体分子对肿瘤标志物蛋白CA125的识别。CA125是检测范围最广、验证最好的卵巢癌生物标志物，但由于现有检测方法缺乏足够的敏感性和特异性，目前不推荐将CA125用于普通人群的筛查。多个癌症生物标志物的同时检测将产生更多的信息分析，包括那些其生物丰度与CA125互补的生物标志物。间硫蛋白和人附睾蛋白4(HE4)是两个相对较新的生物标志物，可以在血清试验中补充CA125。目前，大多数卵巢癌标记物的检测依赖于抗体分子进行选择性识别。抗体的稳定性、可重用性以及使用成像标记或固定化标记进行修饰的能力都受到限制。掺入适体(功能性核酸配体)的分析是抗体技术的一种有吸引力的替代方法。适配子是坚固的、容易标记的，并且完全在体外制备。在以前的研究中，一些适配子已经被证明在与其靶标的亲和力上超过了抗体，这可能转化为在血清测试中改进癌症标记物的检测方法。适体可以取代抗体的另一个应用是将金属纳米粒子显像剂或治疗有效载荷直接靶向卵巢癌细胞表面。这种细胞靶向可能有助于对卵巢肿瘤上生物标记物的分布进行成像，并可能通过热疗实现局部细胞杀伤，从而减少全身化疗的需要。这里提出的研究计划旨在为三个重要的卵巢癌生物标志物开发适配子。然后将开发将这些适配子与敏感的仪器方法结合使用的分析方法。我们还将进行适体功能化纳米颗粒介导高分辨率成像和靶向热疗的原理验证实验。改进癌症筛查的新CA125检测方法的开发和消除肿瘤细胞的创新方法将对公众健康产生积极影响。PI将在威斯康星大学医学院(一年级)主持的为期一年的研究休假期间进行金属纳米颗粒分析。要求再提供两年的支持，在此期间，PI将回到她的家乡奥伯林学院，每年培训两名本科生，并在适体选择和分析开发方面指导他们。一名新近毕业的奥伯林大学本科生将在第三年受聘为全职研究技术员。 公共卫生相关性：这项研究项目的动机是需要为早期卵巢癌开发可靠的非侵入性测试，因为当疾病被早期诊断时，治疗最有效。在卵巢癌女性血液中发现的生物标记物检测被医生广泛使用；我们的目标是开发新的方法来测量三种重要的癌症生物标记物的数量。我们还寻求开发新的方法来观察肿瘤表面并选择性地杀死癌细胞。

DESCRIPTION (provided by applicant): The need persists for better early detection of ovarian cancer. Currently, detection of ovarian cancer relies in part on the recognition of the tumor marker protein CA125 by antibody molecules. CA125 is the most widely assayed and best validated biomarker of ovarian cancer, but because available assays lack sufficient sensitivity and specificity, CA125 is not currently recommended for screening in the general population. More informative assays will result from the simultaneous detection of multiple cancer biomarkers, including those whose biological abundance complements CA125. Mesothelin and human epididymis protein 4 (HE4) are two relatively new biomarkers that may complement CA125 in serum tests. Currently, most assays for ovarian cancer markers rely on antibody molecules for selective recognition. Antibodies are limited in terms of their stability, reusability, and ability to be modified with imaging labels or immobilization tags. Assays incorporating aptamers (functional nucleic acid ligands) are an attractive alternative to antibody-based techniques. Aptamers are robust, easily labeled, and prepared entirely in vitro. In previous studies, some aptamers have been shown surpass antibodies in affinity for their target, which may translate into improved detection methods for cancer markers in serum tests. An additional application in which aptamers may replace antibodies is in targeting metal nanoparticle imaging agents or therapeutic payloads directly to surfaces of ovarian cancer cells. Such cell targeting may be useful for imaging the distribution of biomarkers on ovarian tumors and may enable localized cell killing by hyperthermia, reducing the need for systemic chemotherapy. The research plan proposed here aims to develop aptamers for three important ovarian cancer biomarkers. Assays that use these aptamers in conjunction with sensitive instrumental methods will then be developed. We will also perform proof-of-principle experiments in which aptamer-functionalized nanoparticles mediate high-resolution imaging and targeted hyperthermia. Public health will be positively impacted by the development of new CA125 assays to improve cancer screening and by innovative approaches to tumor cell eradication. The PI will conduct the metal nanoparticle assays during a one-year research sabbatical hosted at the University of Wisconsin Medical School (Year 1). Two additional years of support are requested during which the PI, back at her home institution of Oberlin College, will train two undergraduate students per year and mentor them in aptamer selection and assay development. A recently graduated Oberlin undergraduate will be employed as a full-time research technician in Year 3. PUBLIC HEALTH RELEVANCE: This research project is motivated by the need to develop reliable non-invasive tests for early stage ovarian cancer, since treatment is most effective when the disease is diagnosed early. Tests for biomarkers found in the blood of women with ovarian cancer are widely used by physicians; our goal is to develop new ways of measuring the amounts of three important cancer biomarkers. We also seek to develop new methods for looking at the surfaces of tumors and selectively killing cancer cells.