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

描述（由申请人提供）：需要更好地早期检测卵巢癌。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CA 125的识别。CA 125是卵巢癌最广泛检测和最有效的生物标志物，但由于现有的检测方法缺乏足够的灵敏度和特异性，目前不建议在一般人群中进行筛查。同时检测多种癌症生物标志物，包括那些生物丰度与CA 125互补的生物标志物，将产生更多信息。间皮素和人附睾蛋白4（HE 4）是两个相对较新的生物标志物，可以补充CA 125在血清测试。目前，大多数卵巢癌标志物的测定依赖于抗体分子的选择性识别。抗体在其稳定性、可重复使用性和用成像标记或固定化标签修饰的能力方面受到限制。掺入适体（功能性核酸配体）的测定是基于抗体的技术的有吸引力的替代方案。适体是稳健的，易于标记，并且完全在体外制备。在以前的研究中，一些适体已被证明在对其靶标的亲和力方面超过抗体，这可能转化为血清测试中癌症标志物的改进检测方法。适体可以替代抗体的另一个应用是将金属纳米颗粒成像剂或治疗有效载荷直接靶向卵巢癌细胞的表面。这种细胞靶向可能有助于对卵巢肿瘤上生物标志物的分布进行成像，并且可以通过高温实现局部细胞杀伤，从而减少对全身化疗的需求。这里提出的研究计划旨在为三种重要的卵巢癌生物标志物开发适体。然后将开发使用这些适体与敏感仪器方法结合的测定。我们还将进行适体功能化纳米粒子介导高分辨率成像和靶向热疗的原理验证实验。通过开发新的CA 125检测方法来改善癌症筛查，并通过创新方法根除肿瘤细胞，将对公共卫生产生积极影响。PI将在威斯康星州医学院（第1年）举办的为期一年的研究休假期间进行金属纳米颗粒测定。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，并指导他们进行适体选择和检测开发。最近毕业的奥伯林本科生将在第三年被聘为全职研究技术员。 公共卫生相关性：该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，治疗是最有效的。在卵巢癌患者血液中发现的生物标志物的测试被医生广泛使用;我们的目标是开发测量三种重要癌症生物标志物数量的新方法。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.