EARLY DETECTION OF URINARY BLADDER CANCER

描述(由申请人提供)：该项目的总体目标是开发新的生物标志物和诊断策略，以早期发现隐匿性膀胱肿瘤及其从尿路内癌前病变到浸润性癌症的进展。目前的提议是对早期探测研究网络第一周期期间进行的研究的延伸和合乎逻辑的继续。这些研究已经确定了对膀胱癌的发展至关重要的六个染色体区域，并提供了证据，证明存在一类被称为“先驱”的新基因，其参与先于主要肿瘤抑制基因在癌症发展中的功能丧失。我们假设膀胱癌的原位克隆性扩张是由于与已知的主要抑癌基因如RB1相连的先导基因功能丧失所致。我们利用短干扰RNA进行的体外研究提供了证据，证明这些基因功能的丧失对尿路上皮细胞的生长优势至关重要。因此，识别新的前体基因并研究其在人类膀胱癌早期隐匿期的作用，不仅可能为人类癌症的发生提供重要的机制线索，而且还可能发现一类新的早期检测标记物，能够检测人类癌症发展的临床和显微镜隐匿期。我们还假设了膀胱癌进展的一个互补机制，基于最近发现的致癌蛋白STK15/BTAK/Aurora-A的扩增和过表达，该蛋白参与调节染色体分离和中心体功能，最近能够破坏P53肿瘤抑制蛋白的稳定。在这笔赠款中，我们建议进行以下主要研究： (1)对已确定的与RB1相邻的“先导基因”(ITM2B、P2RY5和CHClL)进行功能分析和评估，作为新的早期检测生物标志物。此外，我们还建议对染色体17p13和5q22-23上的其他预测先导基因进行定位，并评估被确定为膀胱癌检测生物标记物的候选基因。我们还将研究遗传和表观遗传学机制在每个基因功能失活中的作用，以阐明先导基因在恶性转化过程中的作用，这将提高我们检测先导基因的能力，并为早期发现提供临床相关的标记。 (2)STK15/BTAK/Aurora-A及其相互作用基因作为膀胱癌标志物的研究进展。 (3)将STK15/BTAK/Aurora-A及其调控伙伴与先导基因在一个由大约15个标记物组成的小组中结合起来，在前瞻性验证试验中测试它们识别隐匿性膀胱肿瘤的能力。 由于两种主要的新基因，即先驱基因和Aurora-A及其合作伙伴，似乎都与人类癌症的发生有关，因此该项目的完成将对其他常见人类癌症的早期发现具有重大意义。

DESCRIPTION (provided by applicant): The overall goal of this project is to develop novel biomarkers and diagnostic strategies for the early detection of occult urinary bladder neoplasia and its progression from intraurothelial preneoplastic conditions to invasive cancer. The current proposal represents an extension and logical continuation of the studies performed during the first cycle of the Early Detection Research Network (EDRN). These studies have led to the identification of six chromosomal regions critical for the development of bladder cancer and have provided evidence for the existence of a novel class of genes referred to as "forerunners" whose involvement precedes the loss of function of major tumor suppressor genes in the development of cancer. We hypothesize that in situ clonal expansion of bladder preneoplasia is caused by loss of function of the forerunner genes mapping contiguously to known major tumor suppressors such as RB1. Our in vitro studies utilizing short interference RNA provide evidence that loss of function of these genes is critical for growth advantage of urothelial cells. Thus, the identification of novel forerunner genes and the investigation of their involvement in early occult phases of human bladder preneoplasia may not only provide important mechanistic clues to the development of human cancer but may also identify a novel class of early detection markers capable of detecting the clinically and microscopically occult phases of human cancer development. We also hypothesized a complementary mechanism of bladder cancer progression based on the amplification and overexpression of a recently identified oncogenic kinase STK15/BTAK/Aurora-A shown to be involved in regulating chromosomal segregation and centrosome function and more recently to be capable of destabilizing the p53 tumor suppressor protein. In this grant we propose the following major groups of studies: (1) Perform functional analyses and assessment of the already identified putative "forerunner genes" (ITM2B, P2RY5, and CHClL) located contiguously to RB1 as novel early detection biomarkers. Additionally, we propose to characterize other predicted forerunner gene harboring loci mapping on chromosomes 17p13 and 5q22-23 and to assess the candidate genes identified as biomarkers for bladder cancer detection. We will also investigate the contribution of genetic and epigenetic mechanisms in the functional inactivation of each of the genes to elucidate a comprehensive view of the role of forerunner genes in the malignant transformation process that will enhance our ability to detect forerunner genes and provide clinically relevant markers for early detection. (2) Extension of our studies on STK15/BTAK/Aurora-A and its interacting genes involved in the pathway as biomarkers for bladder cancer detection. (3) Combine the STK15/BTAK/Aurora-A and its regulatory partners with the forerunner genes in a panel of approximately 15 markers testing their ability to identify occult bladder neoplasia in a prospective validation trial. Since both major categories of novel genes, i.e. the forerunner genes and Aurora-A with its partners, appear to be universally involved in human carcinogenesis the completion of this project will have major relevance for early detection of other common human cancers.