Cyclic nucleotide phosphodiesterases isoforms as novel biomarkers in CLL

描述(申请人提供)：慢性淋巴细胞性白血病(CLL)是成人白血病中最常见的一种，表现为从快速侵袭性行为到惰性行为的高度多变的临床过程。侵袭性CLL的患者需要早期治疗，而那些惰性CLL的患者通常表现出一种不需要治疗的长期疾病。目前，根据RAI和BINET标准进行的临床分期仍然是决定预后和治疗适应证的基础。然而，根据这些标准，约50%的早期疾病患者发展为更晚期的疾病，并死于CLL或其并发症。重要的是，RAI和BINET分期系统关注的是白血病细胞的数量，而不是特征。新的预后指标，如免疫球蛋白可变区(IgVH)突变状态、CD38和ZAP-70的表达与白血病细胞的分子特征有关，已有报道预测临床病程和总生存期。IgVH状态是一个强大的独立预后因素，但对大多数临床实验室来说，IgVH状态分析是费力、昂贵且难以获得的。白血病细胞CD38和ZAP-70的表达与未突变的IgVH基因表达相关，提示预后不良。然而，目前还没有标准的、广泛使用的程序来评估CD38和ZAP-70的表达。因此，对于B-CLL患者的常规评估，获得最佳预后信息的成本和时间效率的方法是可取的，但目前还不存在。环核苷酸磷酸二酯酶(PDE)催化cAMP和/或cGMP的水解，从而控制它们在细胞内的水平和调节细胞生长和死亡的功能。PDE亚型在疾病细胞中的差异表达有可能影响细胞生理学和识别新的药物靶点。我的初步数据表明，CLL细胞有一种独特的PDE亚型表达谱。因此，这种独特的PDE亚型与CLL中的恶性B细胞有关，并可能提供一种PDE“标志”，可作为这种疾病的生物标记物。定量实时逆转录-聚合酶链式反应(QPCR)已成为一种广泛应用的检测和定量RNA靶标的技术，并越来越多地应用于新的临床诊断方法。定量聚合酶链式反应方法相对简单快速、经济有效，但敏感性和特异性较高，因此建议开展以下研究：1.PDE基因表达模式可作为判断缓解性和侵袭性CLL患者预后的指标。2.在B-CLL患者中，PDE7B基因的表达或PDE7B基因表达与其他PDE亚型的比值可以预测B-CLL患者开始治疗的时间或治疗反应的时间。这些目标的成功完成将为CLL提供一个新的生物标志物，以帮助诊断、预后、预测治疗反应的时间，并可能为这种疾病提供新的治疗方法。与公共卫生相关：慢性淋巴细胞白血病(CLL)是成人白血病中最常见的一种，其临床病程变化很大，从迅速侵袭、需要早期治疗到懒惰行为，这是一种不需要治疗的长寿疾病。目前，还不存在区分这两种形式的CLL的成本和时间高效的方法。在前期研究的基础上，本研究试图量化和建立在CLL中表达唯一改变的环核苷酸磷酸二酯酶(PDE)亚型，它不仅可以提供一个生物标志物，而且可以为这种疾病提供药物靶点。

DESCRIPTION (provided by applicant): Chronic lymphocytic leukemia (CLL), the most common form of adult leukemia, shows a highly variable clinical course spanning from rapidly aggressive to indolent behavior. Patients with aggressive CLL require early treatment while those with indolent CLL generally exhibit a long-lived disease without need of therapy. Currently, clinical staging by the Rai and Binet criteria remains the foundation for determining prognosis and indication for treatment. However, ~50% of patients with early-stage disease, as defined by those criteria, develop more advanced disease and die of CLL or its complications. Importantly, the Rai and Binet staging systems focus on the quantity, rather than on the characteristics, of the leukemic cells. New prognostic indicators, such as the mutational status of the immunoglobulin variable heavy chain region (IgVH), expression of CD38 and ZAP-70 are linked to the molecular characteristics of leukemic cells and have been reported to predict the clinical course and overall survival. IgVH status is a strong independent prognostic factor but IgVH status analysis is laborious, costly and inaccessible for most clinical laboratories. Leukemia-cell expression of CD38 and ZAP-70 was found to correlation with the expression of unmutated IgVH genes to predict a poor prognosis. However, there are no standard, widely used procedures to assess CD 38 and ZAP-70 expression. For routine evaluation of B-CLL patients, a cost- and time-efficient method to obtain optimal prognostic information is thus desirable but does not yet exist. Cyclic nucleotide phosphodiesterases (PDE) catalyze the hydrolysis of cAMP and/or cGMP, thereby controlling their intracellular levels and ability to regulate functions that include cell growth and death. The differential expression of PDE isoforms in diseased cells has the potential to influence cell physiology and identify new drug targets. My preliminary data indicate that CLL cells have a unique profile of expression of PDE isoforms. This unique PDE isoform profile thus relates to the malignant B cells in CLL and may provide a PDE "signature" that could serve as a biomarker for this disease. QPCR (quantitative real-time reverse transcription-PCR) has become a widely used technique for the detection and quantification of RNA targets and is increasingly used in novel clinical diagnostic assay. QPCR methods are relatively simple and rapid, cost-effective, yet sensitive and specific, therefore propose to undertake studies to address the following Specific Aims: 1. The PDE mRNA expression pattern may serve as a prognostic marker to classify patients with indolent and aggressive CLL. 2. The mRNA expression of PDE7B or the ratio of PDE7B mRNA expression vs. that of other PDE isoforms may predict time to initiation of treatment, or response to treatment, in B-CLL patients. Successful completion of these aims will provide a new biomarker in CLL to aid in the diagnosis, prognosis, prediction of time to an response to treatment and possibly suggest new therapeutic approaches for this disease. PUBLIC HEALTH RELEVANCE: Chronic lymphocytic leukemia (CLL), the most common form of adult leukemia, shows a highly variable clinical course spanning from rapidly aggressive, requiring early treatment to indolent behavior, which presents a long- lived disease without need of therapy. Currently, a cost and time efficient method to differentiate between these two forms of CLL does not exist. Based on preliminary studies the proposed research seeks to quantify and establish that cyclic nucleotide phosphodiesterases (PDE) isoforms whose expression is uniquely changed in CLL, may not only provide a biomarker, but also provide the drug target for this disease.