Aptamers as Proteomic Tools for Pancreatic Cancer Biomarker Identification

 描述（由申请人提供）：胰腺癌的症状通常是非特异性和晚期的。现有的血液肿瘤生物标志物，如碳水化合物抗原19-9（CA 19 -9），不够敏感和特异，不能作为有用的筛查试验。早期检测的工具可以增加在早期诊断并可能通过手术切除治愈的患者比例。适体是寡核苷酸（RNA或DNA）分子，其以高特异性直接结合蛋白质，并且可用于鉴定新生物标志物和检测体液中的生物标志物的双重目的。我们使用了一种新的选择方法（称为分泌组选择）来鉴定与培养的胰腺癌细胞分泌的蛋白质结合但不与非癌性胰腺细胞分泌的蛋白质结合的适体。一个成功的适体结合亲环素B（CypB），这是一种以前没有被研究为胰腺癌血液生物标志物的蛋白质。我们已经证明CypB血清水平在胰腺癌患者和健康志愿者之间具有很好的区分性，但在胰腺癌患者和良性胰腺疾病患者之间没有那么好。我们的主要假设是，类似的阳性/阴性适体选择策略可以应用于胰腺癌和良性胰腺疾病患者的血清样品，以鉴定胰腺癌特异性的新型血清生物标志物。该项目的具体目的是：1）使用应用于人类患者血液样品的适体选择策略来鉴定额外的胰腺癌生物标志物。 2)开发基于这些选定适体（包括CypB适体）的检测方法，可用于临床检测血液生物标志物。 3)回顾性评价这些候选生物标志物是否可以区分早期胰腺癌患者、良性胰腺疾病患者和未受影响的患者。该项目的成功完成将导致新的生物标志物的鉴定，可能是有用的， 胰腺癌的诊断、分期和/或治疗。此外，这种生物标志物选择方法可以推广到需要更好生物标志物的其他癌症。

 DESCRIPTION (provided by applicant): The symptoms of pancreatic cancer are usually non-specific and late. Existing blood tumor biomarkers, such as carbohydrate antigen 19-9 (CA19-9), are not sensitive and specific enough to serve as useful screening tests. Tools for earlier detection could increase the proportion of patients who are diagnosed at early stages and potentially cured with surgical resection. Aptamers are oligonucleotide (RNA or DNA) molecules that directly bind to proteins with high specificity and can be used for the dual purpose of identifying novel biomarkers and detecting them in body fluids. We used a novel selection method (known as secretome selection) to identify aptamers that bind to proteins that are secreted by cultured pancreatic cancer cells but not to those secreted by non-cancerous pancreatic cells. One winning aptamer from this selection binds Cyclophilin B (CypB), a protein that has not previously been investigated as a blood biomarker for pancreatic cancer. We have demonstrated that CypB serum levels discriminate well between pancreatic cancer patients and healthy volunteers but not as well between patients with pancreatic cancer and patients with benign pancreatic disease. Our primary hypothesis is that a similar positive/negative aptamer selection strategy can be applied to serum samples from patients with pancreatic cancer and benign pancreatic disease to identify novel serum biomarkers that are specific for pancreatic cancer. The specific aims of this project are: 1) To identify additional pancreatic cancer biomarkers using an aptamer selection strategy applied to blood samples from human patients. 2) To develop assays based on these selected aptamers (including the CypB aptamer) that could be used clinically for the detection of blood biomarkers. 3) To retrospectively evaluate whether these candidate biomarkers can distinguish between patients with early pancreatic cancer, patients with benign pancreatic diseases, and unaffected patients. The successful completion of this project will lead to the identification of new biomarkers that may be useful for the diagnosis, staging, and/or treatment of pancreatic cancer. Moreover, this approach to biomarker selection can be generalized to other cancers for which better biomarkers are needed.