Gene Expression Profiling/Chronic Lymphocytic Leukemia

基因表达谱/慢性淋巴细胞白血病

• 批准号: 7321765
• 负责人: adrian u wiestner
• 金额: --
• 依托单位: NATIONAL HEART, LUNG, AND BLOOD INSTITUTE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7321765
• 关键词: Gene; Expression; Profiling; Chronic; Lymphocytic

We are analyzing gene expression patterns in leukemia cells from patients with chronic lymphocytic leukemia (CLL) that we obtain from peripheral blood, bone marrow and lymph nodes. Our hypothesis is that the leukemic cells receive essential proliferation and survival signals in the bone marrow and/or lymph node. We have analyzed 8 matched pairs of bone marrow and blood derived CLL cells. Consistent with our hypothesis we found that CLL cells from the bone marrow showed a higher expression of genes associated with proliferation as well as a couple hundred genes that may relate to the specific signals induced in the leukemic cells by specific signals provided by the bone marrow microenvironment. We are extending this study now to lymph node samples and are following up on candidate molecules that could play a role in stimulating CLL cell survival. In addition, we are establishing models in vitro where we can show that the survival of CLL cells is extended by co-culture with strom cells. From these studies we hope to identify which signaling pathways are essential for leukemic cell survival and which therefore could be good targets of new therapies. In a second part of the project we obtain CLL cells from patients who undergo therapy with two of the most active drugs in CLL therapy; rituximab and fludarabine. This therapy is given over a 6 day period and repeated every 4 weeks for 6 cycles. Patients donate blood every day during the first 6 treatment days and we analyze the changes in gene expression in these cells due to the therapy. Rituximab, a monoclonal anti-CD20 antibody, is used to treat Chronic Lymphocytic Leukemia (CLL) in combination with fludarabine. Rituximab is thought to deplete B-cells through antibody-dependent cellular cytotoxicity, complement-dependent cytotoxicity, and possibly signaling for apoptosis. Whether or not signaling by rituximab contributes to its clinical efficacy and can sensitize the malignant cells to chemotherapy is controversial. To investigate if rituximab can induce a specific gene expression signature, we used gene expression profiling of B-cells from CLL patients receiving their first rituximab infusion. During the infusion, patients experienced a cytokine release syndrome (fever, chills, and hypotension) that led to interruption and symptomatic treatment in most; however, all patients were able to finish the treatment. We so far have analyzed CD19+ selected CLL cells from eight patients obtained pre and 6 and 24 hours after the start of rituximab. We identified a distinct set of genes important in immune regulation and inflammation that were upregulated in response to rituximab. The majority of these genes were at least 2-fold up-regulated at 6 hours, but most returned to pre-treatment levels by 24 hours. Thus, rituximab induced a transient gene expression signature that correlated with the cytokine release syndrome during the infusion. Ongoing studies aim to better characterize rituximab signaling in CLL and to determine whether this can contribute to apoptosis or sensitize the leukemic cells to chemotherapy.These results will improve our understanding on how these drugs kill the leukemic cells and may help to further improve therapeutic drug combinations.

我们正在分析我们从外周血，骨髓和淋巴结中获得的慢性淋巴细胞性白血病（CLL）的白血病细胞中的基因表达模式。我们的假设是，白血病细胞在骨髓和/或淋巴结中接受基本的增殖和存活信号。我们已经分析了8对匹配的骨髓和血液衍生的CLL细胞。与我们的假设一致，我们发现来自骨髓的CLL细胞显示出与增殖相关的基因表达较高，以及几百个基因，这些基因可能与骨髓微环境提供的特定信号有关，与白血病细胞引起的特定信号有关。我们现在将这项研究扩展到淋巴结样本，并跟随可能在刺激CLL细胞存活中发挥作用的候选分子。此外，我们正在体外建立模型，可以证明CLL细胞的存活是通过与Strom细胞共培养扩展的。从这些研究中，我们希望确定哪种信号通路对于白血病细胞存活至关重要，因此可能是新疗法的良好靶标。 在项目的第二部分中，我们从接受CLL治疗中两种最活跃的药物接受治疗的患者那里获得CLL细胞。利妥昔单抗和氟达拉滨。该疗法在6天的时间内进行，每4周重复一次，以进行6个周期。患者每天在前6个治疗日每天捐赠血液，我们分析由于治疗而导致的这些细胞中基因表达的变化。利妥昔单抗是一种单克隆抗CD20抗体，用于治疗慢性淋巴细胞性白血病（CLL）与氟达拉滨结合使用。利妥昔单抗被认为可以通过抗体依赖性细胞毒性，补体依赖性细胞毒性以及可能引起凋亡的信号来消耗B细胞。利妥昔单抗发信号是否有助于其临床功效，并且可以使恶性细胞对化学疗法的敏感性敏感。为了研究利妥昔单抗是否诱导特定的基因表达特征，我们使用了接受其第一个利妥昔单抗输注的CLL患者的B细胞的基因表达分析。在输注过程中，患者患有细胞因子释放综合征（发烧，发冷和低血压），导致大多数人中断和有症状的治疗。但是，所有患者都能够完成治疗。到目前为止，我们已经分析了利妥昔单抗开始后6和24小时获得的八名患者的CD19+选定的CLL细胞。我们确定了一组在免疫调节和炎症中重要的基因，这些基因响应利妥昔单抗而上调。这些基因中的大多数在6小时时至少上调了2倍，但大多数恢复了24小时的预处理水平。因此，利妥昔单抗诱导了与输注过程中细胞因子释放综合征相关的瞬时基因表达特征。正在进行的研究旨在更好地表征CLL中的利妥昔单抗信号传导，并确定这是否可以有助于凋亡或使白血病细胞对化学疗法敏感。这些结果将提高我们对这些药物如何杀死白血病细胞的理解，并可能有助于进一步改善治疗药物组合。