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

描述（由申请人提供）：对卵巢癌更好的早期检测的需求持续存在。目前，卵巢癌的检测部分依赖于抗体分子对肿瘤标记蛋白CA125的识别。CA125是卵巢癌检测最广泛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敏感性和特异性，CA125目前不推荐用于普通人群的筛查。同时检测多种癌症生物标志物，包括那些生物丰度与CA125互补的标志物，将产生更多信息丰富的分析。间皮素和人附睾蛋白4 （HE4）是两种相对较新的生物标志物，可能在血清试验中补充CA125。目前，大多数卵巢癌标志物的检测依赖于抗体分子的选择性识别。抗体在稳定性、可重用性和成像标签或固定标签修改的能力方面受到限制。结合核酸适体（功能性核酸配体）的检测是一种有吸引力的替代基于抗体的技术。适体健壮，易于标记，完全在体外制备。在先前的研究中，一些适体已经显示出对其靶点的亲和力超过抗体，这可能转化为改进血清检测中癌症标志物的检测方法。适配体可以替代抗体的另一个应用是将金属纳米颗粒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志物的分布进行成像，并可能通过热疗实现局部细胞杀伤，减少对全身化疗的需求。本文提出的研究计划旨在开发三种重要卵巢癌生物标志物的适配体。然后将开发使用这些适体与敏感仪器方法相结合的检测方法。我们还将进行原理验证实验，其中适配体功能化纳米颗粒介导高分辨率成像和靶向热疗。开发新的CA125检测方法以改进癌症筛查和采用创新方法根除肿瘤细胞，将对公共卫生产生积极影响。PI将在威斯康星大学医学院举办的为期一年的研究休假期间（一年级）进行金属纳米颗粒分析。另外两年的支持要求，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，并指导他们选择适体和试验开发。刚毕业的奥伯林本科生将在三年级被聘为全职研究技术人员。

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.