Role of Tcl1 and Par-4 in regulation of chronic lymphocytic leukemia

Tcl1和Par-4在慢性淋巴细胞白血病的调节中的作用

• 批准号: 8792347
• 负责人: SUBBARAO BONDADA
• 金额: $ 38.14万
• 依托单位: UNIVERSITY OF KENTUCKY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-02-07 至 2016-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8792347
• 关键词: 17p13.1; A Mouse; Affect; Animal Model; Apoptosis; Apoptotic; B lymphoid malignancy; B-Cell Lymphomas; B-Lymphocytes; Basic Science; Biology; Bone Marrow; Cell Aging; Cell Survival; Cells; Cessation of life; Chromosomal translocation; Chronic Lymphocytic Leukemia; Clinical; Clinical Data; Clinical Investigator; Clinical Trials; Collaborations; Development; Disease; Down-Regulation; Elderly; Enhancers; Equilibrium; Family; Family member; GRP gene; GRP78 gene; Genes; Goals; Grant; Growth; Health; Human; Immunoglobulins; In Vitro; Induction of Apoptosis; Laboratories; Leukemic Cell; Lymphoid; Malignant Neoplasms; Mediating; Modality; Modeling; Mus; Mutation; Nature; Non-Hodgkin' s Lymphoma; Normal Cell; Oncogenes; Organ; PAWR gene; Pathway interactions; Patients; Peptides; Phenotype; Play; Predisposition; Protein Tyrosine Kinase; Proteins; Receptor Signaling; Receptors, Antigen, B-Cell; Regulation; Relative (related person); Resistance; Role; Sampling; Signal Pathway; Signaling Molecule; Small Interfering RNA; Small-Cell Lymphoma; Surface; T-Cell Leukemia; T-Cell Receptor; T-Lymphocyte; Testing; Therapeutic; Therapeutic Effect; Transcription Factor AP-1; Transgenic Mice; Transgenic Organisms; Translating; Tumor Suppressor Proteins; Western World; Whole Blood; adult leukemia; base; cancer cell; cell age; cell killing; chemotherapy; clinically relevant; cytotoxic; efficacy testing; extracellular; genetic approach; in vivo; inhibitor/antagonist; killings; member; molecular marker; mouse model; neoplastic cell; novel; outcome forecast; overexpression; peripheral blood; pre-clinical; preclinical study; pro-apoptotic protein; promoter; receptor; response; therapy development; transcription factor; treatment strategy; tumor

DESCRIPTION (provided by applicant): Chronic lymphocytic leukemia (CLL), also known as small cell lymphoma, constitutes almost 30% of all cases of non-Hodgkin's lymphoma. It is the most common adult leukemia. Despite advances in chemotherapy, treatment options for CLL patients are limited with only a modest efficacy, especially for patients with unmutated types of B cell receptors (BCR), del (17p13.1) and p53 mutations. Tcl-1, an oncogene, initially found to be translocated in T-cell leukemias, has been found to be expressed at higher levels in CLL phenotypes that are classified as aggressive. A mouse model for CLL has been generated by expressing the Tcl-1 oncogene in B cells using immunoglobulin promoter and the Eμ enhancer. These mice reproducibly develop CLL in 13-18 months and have been shown to be excellent models for human CLL. Par-4 is a pro-apoptotic tumor suppressor, discovered by us, that induces apoptosis in cancer but not normal cells using both the Fas pathway and by inhibiting NF-κB. We made four novel observations. First, the B-cell receptor signaling pathway is active both in the human CLL cells and in the Eμ-Tcl-1 mouse model of CLL as reflected by constitutive activation of Src family protein tyrosine kinases (SFK). Second, we discovered that expression of Tcl1 is down regulated upon inhibition of SFK suggesting a role for BCR signaling in Tcl1 expression. Third we found that expression of Par-4 is down-regulated in Eμ-Tcl1 CLL cells compared to normal mice, while its expression has been found to be variable in human CLL cells. Fourth we discovered that Eμ-Tcl1 cells are killed by soluble Par-4 and SAC, a specific domain of Par-4 that is cytotoxic only to tumor cells. Based on these observations we hypothesize that a balance between Tcl1 and Par-4 regulated by BCR signaling decides the fate of CLL cells between survival and death. We have three specific aims. Aim 1 will determine the importance of BCR signaling and the role of specific SFKs in the regulation of Tcl-1 and Par-4 expression using the Eμ-Tcl-1 mouse model of CLL. Aim 2 will investigate the importance of Par-4 overexpression for CLL development using a newly generated inducible Par-4 transgenic mice mouse model and the Eμ-Tcl-1 mice. Aim 2 will involve preclinical studies to test the efficacy of extracellular Par-4 and SAC to inhibit CLL growth in the Eμ-Tcl-1 mouse model. The relative importance of Tcl-1 and Par-4 will be studied in Aim 3 with primary CLL cells from patients, thus translating the basic research findings in Aims 1 and 2 to clinical samples. The collaboration between UK and OSU provides us an opportunity to integrate the basic science and pre-clinical findings from the first two Aims with studies in Aim 3 using patient derived CLL cells. The exciting aspect of these studies is the possibility that soluble Par-4 or SAC can be developed into a treatment strategy for CLL cells either in isolation or in combination with SFK inhibitors or other targets that are currently being investigated in our laboratories.

描述(申请人提供)：慢性淋巴细胞性白血病(CLL)，也被称为小细胞淋巴瘤，几乎占所有非霍奇金淋巴瘤病例的30%。这是最常见的成人白血病。尽管化疗取得了进展，但CLL患者的治疗选择有限，疗效不高，特别是对B细胞受体(Bcr)、del(17p13.1)和p53突变类型的患者。TCL-1是一种癌基因，最初被发现在T细胞白血病中易位，现已发现在被归类为侵袭性的CLL表型中表达水平较高。利用免疫球蛋白启动子和E-μ增强子在B细胞中表达TCL-1癌基因，建立了小鼠慢性淋巴细胞性白血病模型。这些小鼠在13-18个月内可重复发育成CLL，已被证明是研究人类CLL的优秀模型。PAR-4是我们发现的一种促凋亡的肿瘤抑制因子，它通过Fas途径和抑制NF-κB诱导癌细胞而不是正常细胞的凋亡。首先，B细胞受体信号通路在人类慢性淋巴细胞性白血病细胞和Eμ-TCL-1小鼠模型中都是活跃的，反映在src家族蛋白酪氨酸激酶的结构性激活上。第二，我们发现抑制SFK后，TCL1的表达下调，提示BCR信号在TCL1的表达中起作用。第三，我们发现与正常小鼠相比，PAR-4在Eμ-TCL1CLL细胞中的表达下调，而在人CLL细胞中的表达是可变的。第四，我们发现 Eμ-TCL1细胞被可溶性PAR-4和SAC杀死，SAC是PAR-4的一个特定结构域，只对肿瘤细胞具有细胞毒性。基于这些观察，我们推测，受BCR信号调控的TCL1和PAR-4之间的平衡决定了CLL细胞在生存和死亡之间的命运。我们有三个具体目标。目的1利用慢性淋巴细胞性白血病Eμ-TCL-1小鼠模型，研究bcr信号转导的重要性以及特定的单核细胞激活因子在调节Tcl1和PAR 4表达中的作用。目的2利用新建立的可诱导的PAR-4转基因小鼠模型和Eμ-TCL-1小鼠模型，探讨PAR-4过表达在慢性淋巴细胞白血病发生发展中的作用。目的2将包括临床前研究，以测试细胞外PAR-4和SAC在Eμ-TCL-1小鼠模型中抑制CLL生长的有效性。TCL-1和PAR-4的相对重要性将在AIM 3中用患者的原代CLL细胞进行研究，从而将AIMS 1和2中的基本研究成果转化为临床样本。英国和俄亥俄州立大学之间的合作为我们提供了一个机会，将前两个AIMS的基础科学和临床前发现与AIM 3中使用患者来源的CLL细胞的研究相结合。这些研究的令人兴奋的方面是，可以将可溶性PAR-4或SAC开发为CLL细胞的治疗策略，无论是孤立地还是与SFK抑制剂或我们实验室目前正在研究的其他靶点相结合。