Molecular Mechanism of Lymphomagenesis

淋巴瘤发生的分子机制

• 批准号: 7733524
• 负责人: Mark Raffeld
• 金额: $ 20.32万
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 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/7733524
• 关键词: Automobile Driving; B-Cell Lymphomas; Biological; Blood; Bortezomib; CCAAT-Enhancer-Binding Protein-beta; Cell Death; Cell Line; Cells; Chromosomes, Human, Pair 2; Clinical; Collaborations; Cyclin D1; Data; Data Reporting; Development; Diagnostic; Disease; Drug Delivery Systems; Event; Feedback; Gene Expression; Genes; Germany; Goals; Growth; Ki-1 Large-Cell Lymphoma; Laboratories; Link; Lip structure; Lymphoma; Lymphomagenesis; MAP Kinase Gene; MDM2 gene; MDM2 gene; Malignant Neoplasms; Mantle Cell Lymphoma; Manuscripts; Maps; Modeling; Molecular; Oncogenic; PI3K/AKT; Pathology; Pathway interactions; Phosphorylation; Phosphotransferases; Prognostic Marker; Proteasome Inhibitor; Protein Isoforms; Proto-Oncogene Proteins c-akt; Publishing; Receptor Signaling; Receptors, Antigen, B-Cell; Reporting; Research; Research Personnel; Role; STAT3 gene; SYK gene; Sampling; Series; Signal Pathway; Signal Transduction; Simulate; T-Cell Lymphoma; TP53 gene; Therapeutic; Work; anticancer research; base; cell growth; cyclin D2; cytotoxicity; inhibitor/antagonist; interest; leukemia; mutant; nutlin 3; research study; therapeutic target; transcription factor; ubiquitin ligase

In the last few years, our studies of mantle cell lymphoma (MCL) have been focused on developing a cellular signaling map of this lymphoms to better understand the factors driving cell growth, and to identify potential therapeutic targets and prognostic markers. As a first approach, we initiated studies investigating the potential significance of important cellular kinases known to be involved in proliferation and survival pathways in cell line models as well as in primary samples. We recently published studies showing that aggressive (blastoid) MCL differs from typical MCL as a result of PI3K/AKT pathway activation (Blood, 2006). Cell lines that simulate blastoid MCL and primary blastoid MCL cases show phosphorylation of multiple downstream AKT targets, while typical MCL do not. We are pursuing studies to identify the mechanism by which AKT is activated by assessing components upstream of AKT, including PI3K signaling components and the B-cell receptor (BCR) signaling pathway. Our most recent data indicates that signaling through the BCR-associated SYK kinase is necessary for activation of AKT to occur. Furthermore, we demonstrate that combinations of drugs that target both the PI3K/AKT pathway and the B-cell receptor (BCR) signaling pathway have synergistic activity against MCL, suggesting a therapeutic approach. We are currently preparing two manuscripts to report these data. In a related study focused on MCL therapy (Clinical Cancer Research, in press), we have shown that Nutlin-3, a small molecular inhibitor of the ubiquitin-ligase MDM2, is highly effective in inducing cell death in MCL with wild-type TP53 and also has activity in MCL with mutant TP53. We also provide data concerning the mechanism of activity of Nutlin-3 in both wild-type TP53 and mutant TP-53 bearing MCL cells. Furthermore, we show that the combination of Nutlin-3 with the proteasome inhibitor Bortezomib results in synergistic cytotoxicity in MCL cells harboring either wild-type or mutant TP53. These results provide a basis for the rational use of Nutlin-3 in MCL either alone or in combination with other compounds known to have activity in MCL. We are also continuing to work with Dr. Leticia Quintanilla-Martinez (Tuebingin, Germany), a former fellow in my laboraory, on the role of Cyclin D1 in mantle cell lymphomagenesis. In these studies we have shown that Cyclin D1 is not necessary for mantle cell lymphoma survival (Leukemia 2008). Furthermore through the use of si-RNA targeting Cyclin D1, we demonstrate the existence of a compensatory feedback loop with Cyclin D2 that allows cells to continue growing following Cyclin D1 knockdown. These studies, initiated in our laboratory several years ago, are now primarily being performed in Dr. Quintanilla-Martinez's laboratory. In anaplastic large cell lymphoma (ALCL), we have focused on uncovering the signaling links between the abnormally activated ALK kinase and the development of the lymphoma through a series of targeted inhibition experiments, combined with expression analysis. We recently showed that the abnormally expressed ALK kinase results in the activation of the C/EBP beta transcription factor, which had not previously been shown to be expressed in ALCL (Blood. 2006). We also found that the LIP isoform was preferentially expressed in ALCL, which also occurs in other aggressive cancers. Our current studies indicate that C/EBP beta is critical for ALCL cell growth, and that its activation occurs through two independent convergent pathways activated by the ALK kinase (manuscript under review). Other investigators have reported that ALK activates STAT3, and that STAT3 is necessary for ALCL survival. Our study indicates that STAT3 is required for C/EBP beta gene expression, suggesting that at least one of the critical STAT3 targets is C/EBP beta. Biological activity of C/EBP beta also requires critical phosphoylation events, and our studies indicate that MAPK activation by ALK is also necessary for C/EBP beta activity. This is an unusual example of a proximal oncogenic event activating a downstream target through two convergent pathways, one acting at the transcriptional level (STAT3) and the second, at the post-transcriptional level (MAPK). Studies are ongoing in collaboration with Dr. Leticia Quintanilla-Martinez to identify genes controlled by C/EBP beta using targeted knockdown experiments, combined with expression analysis.

在过去的几年中，我们对地幔细胞淋巴瘤（MCL）的研究一直集中在开发该淋巴结的细胞信号图图上，以更好地了解推动细胞生长的因素，并确定潜在的治疗靶标和预后标记。作为第一种方法，我们开始了研究，研究了重要的细胞激酶在细胞系模型以及主要样品中涉及的重要细胞激酶的潜在意义。我们最近发表的研究表明，由于PI3K/AKT途径激活，侵略性（Blastoid）MCL与典型的MCL有所不同（Blood，2006）。模拟Blastoid MCL和原发性Blastoid MCL病例的细胞系显示了多个下游AKT靶标的磷酸化，而典型的MCL则没有。我们正在进行研究，以确定通过评估AKT上游的组件（包括PI3K信号成分和B细胞受体（BCR）信号通路）来激活AKT的机制。我们的最新数据表明，通过BCR相关的SYK激酶发出信号对于激活AKT是必要的。此外，我们证明，针对PI3K/AKT途径和B细胞受体（BCR）信号通路的药物组合具有针对MCL的协同活性，这表明一种治疗方法。我们目前正在准备两个手稿以报告这些数据。在一项针对MCL疗法的相关研究（临床癌症研究，印刷中）中，我们表明，Nutlin-3是泛素 - 链氨基 - 链酸酶MDM2的小分子抑制剂，在MCL中具有野生型TP53的MCL中非常有效，并且在MCL中也具有MCL的活性。我们还提供了有关野生型TP53和突变型TP-53轴承MCL细胞的Nutlin-3活性机理的数据。 此外，我们表明，Nutlin-3与蛋白酶体抑制剂硼替佐米的组合在具有野生型或突变体TP53的MCL细胞中导致协同的细胞毒性。 这些结果为单独或与已知在MCL活性的其他化合物结合使用Nutlin-3的合理使用提供了基础。我们还将继续与我的实验室的前研究员Leticia Quintanilla-Martinez（德国Tuebingin）博士合作，探讨了Cyclin D1在地幔细胞淋巴疗法中的作用。在这些研究中，我们表明细胞周期蛋白D1对于地幔细胞淋巴瘤存活不是必需的（Leukemia 2008）。此外，通过使用靶向细胞周期蛋白D1的Si-RNA，我们证明了具有Cyclin D2的代偿反馈回路的存在，从而使细胞Cyclin D1敲低后可以继续生长。这些研究是在几年前在我们的实验室发起的，现在主要是在昆塔尼拉·马丁内斯博士的实验室进行的。在肿瘤大型细胞淋巴瘤（ALCL）中，我们专注于发现异常活化的ALK激酶与淋巴瘤的发展之间的信号传导联系，并结合表达分析。我们最近表明，异常表达的ALK激酶会导致C/EBPβ转录因子的激活，以前尚未证明在ALCL中表达（血液，2006年）。我们还发现，唇部亚型优先在ALCL中表达，这也发生在其他侵略性癌症中。我们目前的研究表明，C/EBPβ对ALCL细胞的生长至关重要，并且其激活是通过ALK激酶激活的两种独立的收敛途径（正在综述的手稿）进行的。其他研究人员报告说，ALK激活了STAT3，而STAT3对于ALCL生存是必需的。我们的研究表明，C/EBPβ基因表达需要STAT3，这表明至少一个关键STAT3目标是C/EBPβ。 C/EBPβ的生物学活性也需要关键的磷酸化事件，我们的研究表明，ALK的MAPK激活对于C/EBPβ活性也是必需的。这是一个不寻常的例子，即通过两个收敛途径激活下游目标，一个在转录级别（STAT3）（STAT3）和第二个转录后级别（MAPK）激活下游目标。研究正在与Leticia Quintanilla-Martinez博士合作，以使用靶向的敲低实验与表达分析结合使用C/EBPβ控制。