Genetic Analysis of T Cell Leukemogenesis

T 细胞白血病发生的遗传分析

• 批准号: 8333011
• 负责人: STEPHEN J. BRANDT
• 金额: --
• 依托单位: VETERANS HEALTH ADMINISTRATION
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8333011
• 关键词: Acute Lymphocytic Leukemia; Acute T Cell Leukemia; Affect; Age; BHLH Protein; Behavior; Binding Proteins; C-terminal; Cell Line; Cell Survival; Cell Transplantation; Cell physiology; Cells; Cellular biology; Chromosomal Rearrangement; Chromosomal translocation; Complex; DNA Binding; Development; Dimerization; Disease; Family; Funding; Gene Proteins; Gene Targeting; Genetic Transcription; Head and neck structure; Helix-Turn-Helix Motifs; Individual; LIM Domain; LIM Domain Protein; Lead; Lymphoid Cell; Malignant Neoplasms; Mediating; Military Personnel; Mono-S; Mus; N-terminal; Neuroblastoma; Nuclear Proteins; Oncogenic; Protein Family; Proteins; RNA Interference; Role; SS DNA BP; Single-Stranded DNA; T cell therapy; T-Cell Development; T-Lymphocyte; Testing; Therapeutic Effect; Transgenic Mice; Work; bHLH Domain; gain of function; genetic analysis; in vivo; insight; knock-down; leukemia; leukemic stem cell; leukemogenesis; lymphoblast; male; malignant breast neoplasm; malignant phenotype; mouse model; novel; polypeptide; protein complex; therapeutic target; tumor

DESCRIPTION (provided by applicant): PROJECT SUMMARY Aberrant expression of a family of basic helix-loop-helix (bHLH) transcription factors and two LIM domain-containing transcriptional adaptors, LIM-only protein 1 (LMO1) and 2 (LMO2), constitute the most frequent gain-of-function abnormalities in T-cell acute lymphoblastic leukemia (T-ALL). This can result from either chromosomal translocation or dysregulated mono- or bi-allelic expression. The protein products of these genes contribute to a common DNA-binding complex that also contains the LIM domain-binding protein Ldb1 and two Ldb1-interacting proteins, single stranded DNA-binding protein-2 (SSBP2) and -3 (SSBP3). This or a related complex mediates the oncogenic actions of these nuclear proteins by activating and repressing the transcription of specific sets of target genes. Although the importance of both bHLH and LMO proteins to the development of T-ALL is well established, how this multi-protein complex contributes to the phenotype of the malignant lymphoblast and whether interactions between its component proteins can be targeted for therapeutic purpose are not known. We have determined that the SSBPs protect Ldb1 and LMO proteins from ubiquitylation and proteasomal destruction and, through a separate mechanism, promote Ldb1 dimerization. We hypothesize that reducing Ldb1 expression or inhibiting its interaction with itself, SSBPs, or LMO proteins will adversely affect leukemia cell survival, proliferation, and/or function. This wil be tested in three specific aims. In the first aim, the effects of reducing Ldb1 expression by RNA interference will be tested on the viability, number, and invasiveness of leukemia cells derived from two transgenic mouse models of T-ALL. In the second aim, the effects of inhibiting Ldb1 interaction with itself, SSBPs, and LMO proteins will be investigated through use of dominant interfering Ldb1-derived polypeptides corresponding to its N-terminal dimerization domain, central Ldb1/Chip conserved domain, and C- terminal LIM interaction domain, respectively. In the third aim, the effects of reducing or inactivating Ldb1 expression will be tested on leukemia-initiating activity (leukemia stem cell function) in vivo in cell transplantation studies. These studies should provide new insights into Ldb1 function in leukemia cell biology and lead to the development of novel targeted therapies for T-ALL and other malignancies characterized by abnormal expression of bHLH and LMO proteins.

描述（由申请人提供）： 项目摘要的基本螺旋环螺旋（BHLH）转录因子的表达和两个含LIM结构域的转录适配器的表达，即lim-hom-hom-hom-hom-hom-hom-hom-hom-hom-hom-hom-hom-hom-hom-hom-hom-hom-hom-on-holy蛋白质和2（LMO2），构成了T-Cell急性淋巴布lymphoblastic Leukemia（T-t-t-t-a构成最常见的功能性收益异常）（这可能是由染色体易位或单位平行表达失调或失调的。这些基因的蛋白质产物有助于一种常见的DNA结合复合物，该复合物还含有LIM结构域结合蛋白LDB1和两种LDB1相互作用蛋白，单链DNA结合蛋白-2（SSBP2）和-3（SSBP3）。该或相关的复合物通过激活和抑制特定靶基因集的转录来介导这些核蛋白的致癌作用。尽管BHLH和LMO蛋白在T-All的发展中的重要性均已确定，但这种多蛋白质复合物如何有助于恶性淋巴细胞的表型，以及其成分蛋白之间的相互作用是否可以针对治疗目的靶向。我们已经确定SSBPS保护LDB1和LMO蛋白免受泛素化和蛋白酶体破坏的影响，并通过单独的机制促进LDB1二聚体。我们假设减少LDB1表达或抑制其与自身，SSBPS或LMO蛋白的相互作用将对白血病细胞存活，增殖和/或功能产生不利影响。将以三个特定目标进行测试。在第一个目的中，将测试通过RNA干扰减少LDB1表达的影响，以源自T-ALL的两个转基因小鼠模型得出的白血病细胞的生存力，数量和侵入性。在第二个目的中，将通过使用与其N末端二聚化结构域，中央LDB1/芯片保存结构域的中央LDB1衍生的多肽以及C-终端限制性相互作用，分别使用抑制LDB1与自身，SSBP和LMO蛋白相互作用，SSBP和LMO蛋白的影响。在第三个目的中，将在细胞移植研究中对体内白血病发射活性（白血病干细胞功能）的减少或灭活LDB1表达的影响。这些研究应提供对白血病生物学中的LDB1功能的新见解，并导致开发用于T-ALL和其他恶性肿瘤的新型靶向疗法，其特征是BHLH和LMO蛋白异常表达。