Dual role of IL-16 in dysregulated growth of CTCL cells

IL-16 在 CTCL 细胞生长失调中的双重作用

• 批准号: 7849964
• 负责人: William W Cruikshank
• 金额: $ 33.64万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7849964
• 关键词: Address; Affect; Antigens; Apoptosis; Binding; Binding Sites; CD7 gene; CREB1 gene; Cell Count; Cell Cycle; Cell Cycle Progression; Cell Line; Cell Nucleus; Cell surface; Cells; Chimeric Proteins; Chromosomes, Human, Pair 15; Code; Cyclin-Dependent Kinase Inhibitor; DNA Sequence; Data; Dipeptidyl-Peptidase IV; Dose; Fluorescent in Situ Hybridization; G0 Phase; Genetic Transcription; Growth; Growth Factor; Human; Hypermethylation; IL16 gene; IL2RA gene; Interleukin-15; Interleukin-16; Interleukin-17; Interleukin-7; Location; MLLT7 gene; Malignant - descriptor; Maps; Methylation; Molecular Chaperones; Mus; Mutation; Nuclear; Nuclear Translocation; Patients; Phase; Phenotype; Point Mutation; Production; Proteins; Proto-Oncogene Proteins c-akt; Regulation; Regulatory T-Lymphocyte; Reporting; Resistance; Role; Scaffolding Protein; Sezary Syndrome; Signal Transduction; Site; Staging; Stem cells; Surface; System; T-Cell Proliferation; T-Lymphocyte; TNFRSF8 gene; Therapeutic; Tumor Suppressor Proteins; Virus; cancer cell; cell growth; competence factor; extracellular; genetic regulatory protein; interleukin 16 precursor; novel strategies; prevent; promoter; protein distribution; public health relevance

DESCRIPTION (provided by applicant): The increase in T cell numbers associated with Sezary Syndrome likely occurs as a result of hyperproliferation as well as decreased apoptosis. The mechanisms involved resulting in these effects however are not clearly understood. We have previously reported that IL-16 is a bi-functional protein involved in regulation of T cell growth. The secreted (mature) portion has been classified as a competence factor that regulates T cell growth through extracellular association with CD4, promoting CD25 expression and transition from the G0 phase to G1. The pro-piece (pro-IL-16) has been recently detected in the nucleus of T cells where it affects proliferation through the regulation of Skp-2 transcription. Pro-IL-16 functions as a scaffold protein which interacts with co- factors GABP1 and HDAC-3 to suppress Skp2 transcription, therefore indirectly regulating degradation of one of the major cyclin kinase inhibitors associated with T cell proliferation, p27kip1. Our preliminary data now indicates that in T cells from CTCL patients there is an initial redistribution of intracellular pro-IL-16 characterized by preferential loss in the nucleus. This loss can be attributable to mutations in the PDZ1 domain, correlating to loss of binding by the nuclear chaperone protein HSC70. The loss of nuclear pro-IL-16 also appears to be combined with an observed increase in secretion of mature IL-16 in stages I-III as intracellular stores become depleted. In addition, there is an overall progressive reduction in the production of IL-16 that may be associated with promoter hypermethylation. It is our hypothesis therefore that the onset of CTCL is associated with hypermethylation of the IL-16 promoter resulting in a progressive reduction in protein production. In addition, mutations in PDZ1 of pro-IL-16 results in loss of HSC70 binding, significantly reducing nuclear expression or function, while increasing secretion of mature protein. Secreted IL-16 interacts with surface expressed CD4 to further induce cell cycle progression in the malignant cells. In these studies we propose to investigate the effects of methylation on the IL-16 promoter as well as within the coding region; to delineate the mechanism by which pro-IL-16 is prevented from nuclear translocation and establish cellular effects of Sezary T cells following expression of wild type pro-IL-16; and finally to determine the role of secreted IL-16 on T cell proliferation and potential expansion of T regulatory cells. PUBLIC HEALTH RELEVANCE: We have shown that nuclear pro-IL-16 functions to regulate T cell progression within the cell cycle and that in Sezary T cells pro-IL-16 has lost the ability to translocate into the nucleus rendering the cells hyperproliferative. In these studies we propose to identity the mechanisms involved in regulating nuclear translocation of pro-IL-16; the ability of expressed wild type pro-IL-16 to regulate hyperproliferation in malignant T cells; and to investigate the role of secreted IL-16 to induce loss of tumor suppressor expression with resultant hyperproliferation. Completion of these studies will not only identify a mechanism for dysregulated growth in Sezary T cells but will elucidate a novel approach to potential therapeutics.

描述（由申请人提供）：与塞扎里综合征相关的 T 细胞数量增加可能是过度增殖和细胞凋亡减少的结果。然而，导致这些影响的机制尚不清楚。我们之前报道过 IL-16 是一种参与调节 T 细胞生长的双功能蛋白。分泌（成熟）部分被归类为能力因子，通过细胞外与 CD4 的结合来调节 T 细胞生长，促进 CD25 表达并从 G0 期过渡到 G1。最近在 T 细胞的细胞核中检测到前片段 (pro-IL-16)，它通过调节 Skp-2 转录来影响增殖。 Pro-IL-16 作为支架蛋白发挥作用，与辅因子 GABP1 和 HDAC-3 相互作用以抑制 Skp2 转录，从而间接调节与 T 细胞增殖相关的主要细胞周期蛋白激酶抑制剂之一 p27kip1 的降解。我们的初步数据现在表明，在来自 CTCL 患者的 T 细胞中，细胞内 pro-IL-16 最初重新分布，其特征是优先在细胞核中丢失。这种损失可归因于 PDZ1 结构域的突变，与核伴侣蛋白 HSC70 的结合损失相关。随着细胞内储存的耗尽，核前 IL-16 的损失似乎还与观察到的 I-III 阶段成熟 IL-16 分泌的增加相结合。此外，IL-16 的产生总体上逐渐减少，这可能与启动子高甲基化有关。因此，我们假设 CTCL 的发病与 IL-16 启动子的过度甲基化有关，导致蛋白质产量逐渐减少。此外，IL-16原的PDZ1突变导致HSC70结合丧失，显着降低核表达或功能，同时增加成熟蛋白的分泌。分泌的 IL-16 与表面表达的 CD4 相互作用，进一步诱导恶性细胞的细胞周期进程。在这些研究中，我们建议研究甲基化对 IL-16 启动子以及编码区内的影响；描述防止 pro-IL-16 核转位的机制，并确定 Sezary T 细胞在野生型 pro-IL-16 表达后的细胞效应；最后确定分泌的 IL-16 对 T 细胞增殖和 T 调节细胞潜在扩增的作用。 公共健康相关性：我们已经证明，核前 IL-16 具有调节细胞周期内 T 细胞进展的功能，并且在 Sezary T 细胞中，前 IL-16 失去了易位到细胞核中的能力，导致细胞过度增殖。在这些研究中，我们建议鉴定参与调节 IL-16 核易位的机制；表达的野生型 IL-16 前体调节恶性 T 细胞过度增殖的能力；并研究分泌的 IL-16 在诱导肿瘤抑制因子表达丧失并导致过度增殖中的作用。这些研究的完成不仅将确定 Sezary T 细胞生长失调的机制，还将阐明潜在治疗的新方法。