Human RNA Binding Protein as a Cancer Marker

描述（由申请人提供）：本提案的目标是确定 如果最近发现的RNA结合蛋白在人类中特异性表达， 癌组织该蛋白质与c-myc mRNA编码区的一段结合 导致mRNA不稳定。这个片段称为编码区 不稳定性决定因素或CRD。与CRD结合的蛋白质是 CRD结合蛋白或CRD-BP。我们发现了CRD-BP使用无细胞mRNA 衰变系我们观察到多核糖体相关的c-myc mRNA特异性地 并且当竞争者RNA对应于 将c-myc CRD加入到反应中。裂解发生在 mRNA。我们推测可能是一种蛋白质保护了CRD， 核酸内切酶攻击且竞争者CRD RNA滴定掉蛋白质 的mRNA。这种蛋白质，CRD-BP，后来被纯化，测序， 在我们的实验室里克隆出来的。我们实验室随后的四次观察显示 CRD-BP和人类癌症之间的密切联系。两项发现表明， CRD-BP是一种癌胚蛋白：（i）CRD-BP在肿瘤细胞中大量表达， 胎儿但成年人没有。(ii)CRD-BP在大多数转化的 人类组织培养细胞。另外两项研究结果表明，CRD-BP是一种 潜在的人类肿瘤标志物：（iii）CRD-BP基因在人肿瘤细胞中扩增。 大约三分之一的人类乳腺癌病例。(iv)CRD-BP是 在一些人结肠癌病例中表达，但在正常结肠中不表达。我们 工作假设是（i）CRD-BP在一些或许多细胞中过表达， CRD-BP可能是一种新的肿瘤标志物。 以下目标/问题探讨了这些假设：CRD-BP是 在结肠癌中过度表达。它是否也在肺、乳腺和 前列腺癌CRD-BP基因在乳腺癌中扩增。是不是也 在结肠癌、肺癌和前列腺癌中的扩增如果是这样，CRD-BP基因 扩增与CRD-BP过表达相关？Aim II.患者是否 结肠癌、肺癌、乳腺癌和前列腺癌会产生CRD-BP抗体？目的 三. CRD-BP本身在结肠、肺、 乳腺癌和前列腺癌目标四。CRD-BP在这些癌症中的表达 与癌症分级或预后较差相关吗？这些研究可以 为临床医生提供了一种新的肿瘤标志物。它们也可能刺激未来 研究以评估CRD-BP作为治疗靶点。

DESCRIPTION (provided by applicant): The goal of this proposal is to determine if a recently discovered RNA-binding protein is expressed specifically in human cancer tissue. The protein binds to a segment of the c-myc mRNA coding region that causes the mRNA to be unstable. This segment is called the Coding Region instability Determinant or CRD. The protein that binds to the CRD is the CRD-Binding Protein or CRD-BP. We discovered the CRD-BP using a cell-free mRNA decay system. We observed that polysome-associated c-myc mRNA was specifically and rapidly degraded by an endonuclease when competitor RNA corresponding to the c-myc CRD was added to the reactions. Cleavage occurred within the CRD of the mRNA. We reasoned that a protein might be shielding the CRD from endonuclease attack and that competitor CRD RNA was titrating the protein off of the mRNA. This protein, the CRD-BP, was later purified, sequenced, and cloned in our laboratory. Four subsequent observations from our lab revealed strong links between the CRD-BP and human cancer. Two findings suggest that the CRD-BP is an oncofetal protein: (i) The CRD-BP is expressed abundantly in fetuses but not in adults. (ii) The CRD-BP is expressed in most transformed human tissue culture cells. Two other findings suggest that the CRD-BP is a potential human tumor marker: (iii) The CRD-BP gene is amplified in approximately one-third of human breast cancer cases. (iv) The CRD-BP is expressed in some cases of human colon cancer but not in normal colon. Our working hypotheses are that (i) the CRD-BP is overexpressed in some or many human carcinomas and (ii) the CRD-BP might therefore be a new cancer marker. The following aims/questions explore these hypotheses: Aim I. The CRD-BP is overexpressed in colon cancer. Is it also overexpressed in lung, breast, and prostate cancers? The CRD-BP gene is amplified in breast cancer. Is it also amplified in colon, lung, and prostate cancers? If so, does CRD-BP gene amplification correlate with CRD-BP overexpression? Aim II. Do patients with colon, lung, breast, and prostate cancer make antibodies to the CRD-BP? Aim III. Is the CRD-BP itself detectable in serum from patients with colon, lung, breast, and prostate cancer? Aim IV. Does CRD-BP expression in these cancers correlate with cancer grade or with a poorer prognosis? These studies could provide clinicians with a novel tumor marker. They might also stimulate future studies to evaluate the CRD-BP as a therapeutic target.