Positive and Negative Regulatory Pathways In Human Lymp*

人类淋巴中的正向和负向调节途径*

• 批准号: 6766983
• 负责人: RICHARD J FORD
• 金额: $ 33.6万
• 依托单位: UNIVERSITY OF TX MD ANDERSON CAN CTR
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-06-25 至 2008-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6766983
• 关键词: B lymphocyte; CD40 molecule; cell growth regulation; cell proliferation; cell surface receptors; clinical research; gel mobility shift assay; gene expression; human tissue; immunocytochemistry; immunoelectron microscopy; immunoprecipitation; mass spectrometry; microarray technology; molecular cloning; nonHodgkin' s lymphoma; nuclear factor kappa beta; protein signal sequence; regulatory gene; transforming growth factors

DESCRIPTION (provided by applicant): Non-Hodgkin's Lymphomas (NHL) are common tumors of the human immune system, primarily of B cell lineage (NHL-B) that have been showing significant unexplained increases in incidence for the last three decades. Unlike normal B-lymphocytes aggressive forms of NHL-B show rapid, dysregulated B lymphocyte growth characteristics, while retaining typical B cell immuno-phenotypes, including expression of characteristic CD40 and SIg. cell surface receptors. Normal B cells, involved in inflammatory, or other immune functions, transduce signals to activate and release, the key transcription factor, NF-kappaB from its cytoplasmic inhibitor; but aggressive NHL-B cells, such as Large B cell Lymphomas (LBCL), show constitutive expression of nuclear NF-kappaB. Our studies have shown that this is accomplished by continually maintaining an assembled, scaffold-like, signaling platform as a concatenate molecular aggregate, called a Signalosome within a lipid raft microdomains, contained within or subjacent to the lymphoma cell membrane. We have developed a hypothetical model of aggressive NHL-B cell pathophysiology that envisions dysregulation of the CD40 mediated signaling pathways as the major mechanism controlling tumor cell growth and other parameters of malignancy. The CD40 Signalosome appears to be initiated through autochthonous production and cognate ligand binding of CD154 (CD40L, gp39) to the CD40 receptor on the lymphoma cell surface. Our studies have indicated that the necessary and sufficient conditions for CD154 expression seem to differ in NHL-B cells from normal activated T lymphocytes, suggesting that the neoplastic lymphocytes show dysregulated gene expression and signaling pathways to mediate autonomous tumor cell growth. Constitutive expression of NF-kappaB in NHL-B can be down-regulated by treatment with specific antibodies or antisense oligos to CD40 or CD154, that disrupt the integrity of the CD40 Signalosomes, resulting in the inhibition of lymphoma cell growth, and the induction of lymphoma cell death in vitro. In this proposal, we will study the molecular characteristics of the CD40 Signalosome, by isolating and sequencing the component proteins of the canonical CD40/NFkB pathway contained within the signalosome, and demonstrate the signaling capabilities of this macromolecular structure. We will also study the signaling pathways controlling gene expression of the CD40 ligand, CD154, that we believe is intimately involved with driving the signalosome pathway, to ascertain the mechanism of its "ectopic" expression, as well as its possible role the aggressive growth pattern and resistance to cell death shown by aggressive NHL-B. In addition to these abnormalities involving lymphoma cell proliferation and cell viability, NHL-B cells also show aberrant expression of the TGF-beta/SMAD-SNO/SKI system, that is responsible for negative growth regulation in normal B lymphocytes (as well as many other functions in most cell types). Our preliminary studies have shown that abnormalities in SNO/SKI gene expression are involved in abrogating the negative regulatory influence of this signaling system in NHL-B that also appears to be linked to the CD40/NFkB system in NHL-B. Our studies will further examine the role of this system in potentiating the biologic, and possibly the clinical aggressiveness of these lymphoid tumors, and explore whether inhibition of the dysregulatory elements in this pathway can have therapeutic potential. We believe that our CD40 Signalosome model will provide an important "roadmap" into the important control mechanisms involved in NHL-B, that can be used for developing new therapeutic approaches for this very important group of human lymphoid neoplasms.

描述（由申请人提供）：非霍奇金的淋巴瘤（NHL）是人类免疫系统的常见肿瘤，主要是B细胞谱系（NHL-B），在过去的三十年中，其发病率已显示出明显的无法解释的增加。 与正常的B淋巴细胞不同，NHL-B的侵袭性形式显示出快速，失调的B淋巴细胞生长特性，同时保留了典型的B细胞免疫 - 光谱型，包括特征CD40和SIG的表达。细胞表面受体。 正常的B细胞，涉及炎症或其他免疫功能，会转导信号激活和释放，即关键转录因子，NF-kappab的NF-kappab来自其细胞质抑制剂；但是，侵袭性的NHL-B细胞（例如大B细胞淋巴瘤（LBCL））显示出核NF-kappab的本构表达。 我们的研究表明，这是通过连续保持组装的，类似支架的信号平台作为脂质筏微域中的信号体的组合物分子聚集体来完成的，该分子聚集体中包含在淋巴瘤细胞膜中或在淋巴瘤细胞膜上包含的信号体。 我们已经开发了一种侵略性NHL-B细胞病理生理学的假设模型，该模型设想CD40介导的信号通路失调，作为控制肿瘤细胞生长和其他恶性肿瘤参数的主要机制。 CD40信号体似乎是通过自动产生和CD154（CD40L，GP39）与淋巴瘤细胞表面上CD40受体的同源配体结合而启动的。 我们的研究表明，在正常活化的T淋巴细胞中，CD154表达的必要条件在NHL-B细胞中似乎有所不同，这表明肿瘤性淋巴细胞显示出基因表达和信号传导途径的失调，以介导自主肿瘤细胞生长。 NF-kappab在NHL-B中的本构表达可以通过特异性抗体或对CD40或CD154的反义寡核酸的处理来下调，从而破坏CD40信号体的完整性，从而抑制淋巴瘤细胞生长，并抑制淋巴瘤细胞死亡的诱导。 在此提案中，我们将通过隔离和测序信号体中包含的规范CD40/NFKB途径的成分蛋白来研究CD40信号体的分子特性，并证明该大分子结构的信号传导能力。 我们还将研究控制CD40配体基因表达CD154的信号传导途径，我们认为，我们认为与驱动信号体途径密切相关，以确定其“异位”表达的机制，以及其可能的作用，其可能的作用是积极的生长模式和对细胞死亡的抗性NHL-B所显示的。 除了涉及淋巴瘤细胞增殖和细胞活力的这些异常外，NHL-B细胞还显示出TGF-β/SMAD-SNO/SKI系统的异常表达，这是正常B淋巴细胞中负调节负调控（以及大多数细胞类型的许多其他功能）。 我们的初步研究表明，SNO/SKI基因表达异常参与了NHL-B中该信号传导系统的负调控作用，这似乎也与NHL-B中的CD40/NFKB系统有关。 我们的研究将进一步研究该系统在增强生物学的作用，甚至可能是这些淋巴样肿瘤的临床攻击性，并探讨该途径中对失调元件的抑制是否可以具有治疗潜力。 我们认为，我们的CD40信号体模型将为NHL-B所涉及的重要控制机制提供重要的“路线图”，该机制可用于为这一非常重要的人类淋巴肿瘤提供新的治疗方法。