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），在过去的三十年中发病率有显著的不明原因的增加。与正常B淋巴细胞不同，侵袭型NHL-B表现出快速、失调的B淋巴细胞生长特征，同时保留典型的B细胞免疫表型，包括CD40和sig细胞表面受体的表达。正常的B细胞，参与炎症或其他免疫功能，转导信号激活和释放关键转录因子NF-kappaB从其细胞质抑制剂；但侵袭性NHL-B细胞，如大B细胞淋巴瘤（LBCL），显示核nf - κ B的组成性表达。我们的研究表明，这是通过持续维持一个组装的、支架样的信号平台作为一个连接的分子聚集体来实现的，这个分子聚集体被称为信号体，位于脂质筏微域内或邻近淋巴瘤细胞膜。我们已经建立了一个侵袭性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是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身产生和同源配体结合CD154 （CD40L, gp39）到淋巴瘤细胞表面的CD40受体而启动的。我们的研究表明，NHL-B细胞表达CD154的必要和充分条件似乎与正常活化的T淋巴细胞不同，这表明肿瘤淋巴细胞通过基因表达和信号通路失调来介导肿瘤细胞的自主生长。NHL-B中NF-kappaB的组成性表达可以通过CD40或CD154的特异性抗体或反意义寡核苷酸处理而下调，从而破坏CD40信号体的完整性，导致淋巴瘤细胞生长受到抑制，并在体外诱导淋巴瘤细胞死亡。在本研究中，我们将通过分离和测序CD40信号体中包含的典型CD40/NFkB通路的组成蛋白来研究CD40信号体的分子特征，并证明这种大分子结构的信号传导能力。我们还将研究控制CD40配体CD154基因表达的信号通路，我们认为CD154与驱动信号体通路密切相关，以确定其“异位”表达的机制，以及它在侵袭性NHL-B表现出的侵袭性生长模式和对细胞死亡的抵抗中可能发挥的作用。除了这些涉及淋巴瘤细胞增殖和细胞活力的异常外，NHL-B细胞还表现出tgf - β /SMAD-SNO/SKI系统的异常表达，该系统负责正常B淋巴细胞的负生长调节（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基因表达的异常参与了NHL-B中该信号系统的负调控作用的消除，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这些淋巴肿瘤的生物学和可能的临床侵袭性中的作用，并探索抑制该途径中的失调元件是否具有治疗潜力。我们相信我们的CD40信号体模型将为NHL-B的重要控制机制提供一个重要的“路线图”，可用于开发针对这一非常重要的人类淋巴样肿瘤群体的新治疗方法。