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.

我们正在分析从外周血、骨髓和淋巴结中获得的慢性淋巴细胞白血病 (CLL) 患者的白血病细胞的基因表达模式。我们的假设是白血病细胞在骨髓和/或淋巴结中接收必要的增殖和生存信号。我们分析了 8 对匹配的骨髓和血液 CLL 细胞。与我们的假设一致，我们发现来自骨髓的 CLL 细胞表现出与增殖相关的基因以及数百个可能与骨髓微环境提供的特定信号在白血病细胞中诱导的特定信号相关的基因的较高表达。 。我们现在正在将这项研究扩展到淋巴结样本，并跟踪可能在刺激 CLL 细胞存活中发挥作用的候选分子。此外，我们正在建立体外模型，通过与基质细胞共培养，可以证明 CLL 细胞的存活时间得到延长。从这些研究中，我们希望确定哪些信号通路对于白血病细胞的存活至关重要，因此哪些信号通路可能成为新疗法的良好靶点。 在该项目的第二部分中，我们从接受 CLL 治疗中两种最活跃药物治疗的患者身上获取 CLL 细胞；利妥昔单抗和氟达拉滨。该疗法持续 6 天，每 4 周重复一次，共 6 个周期。患者在治疗的前 6 天每天都献血，我们分析这些细胞因治疗而发生的基因表达变化。利妥昔单抗是一种单克隆抗 CD20 抗体，与氟达拉滨联合用于治疗慢性淋巴细胞白血病 (CLL)。利妥昔单抗被认为通过抗体依赖性细胞毒性、补体依赖性细胞毒性以及可能的细胞凋亡信号来消耗 B 细胞。利妥昔单抗的信号传导是否有助于其临床疗效以及是否可以使恶性细胞对化疗敏感仍存在争议。为了研究利妥昔单抗是否可以诱导特定的基因表达特征，我们对接受首次利妥昔单抗输注的 CLL 患者的 B 细胞进行了基因表达谱分析。在输注过程中，患者出现细胞因子释放综合征（发烧、寒战和低血压），导致大多数患者中断治疗并接受对症治疗；然而，所有患者都能够完成治疗。到目前为止，我们已经分析了从 8 名患者开始使用利妥昔单抗前以及开始后 6 小时和 24 小时获得的 CD19+ 选择的 CLL 细胞。我们发现了一组在免疫调节和炎症中重要的独特基因，这些基因在利妥昔单抗的作用下上调。这些基因中的大多数在 6 小时内至少上调 2 倍，但大多数在 24 小时内恢复到治疗前的水平。因此，利妥昔单抗诱导了与输注期间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，并确定这是否会导致细胞凋亡或使白血病细胞对化疗敏感。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进治疗药物组合。