Positive and Negative Regulatory Pathways In Lymphoma

淋巴瘤的正向和负向调节途径

• 批准号: 6598247
• 负责人: RICHARD J FORD
• 金额: $ 32.69万
• 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/6598247
• 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)是人类免疫系统常见的肿瘤，主要是B细胞系(NHL-B)，在过去的三十年里，发病率一直在显著上升，原因不明。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，同时保留了典型的B细胞免疫表型，包括特征性CD40和SIG的表达。细胞表面受体。正常的B细胞参与炎症或其他免疫功能，传递信号以激活和释放其胞浆抑制物中的关键转录因子NF-kappaB；而侵袭性的NHL-B细胞，如大B细胞淋巴瘤(LBCL)，显示出核转录因子-kappaB的结构性表达。我们的研究表明，这是通过持续地维持一个组装的、支架状的信号平台作为连接的分子聚集体来实现的，该分子聚集体被称为脂筏微域中的信号小体，包含在淋巴瘤细胞膜内或细胞膜下。我们已经建立了一个侵袭性NHL-B细胞病理生理学假说模型，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CD154(CD40L，gp39)与淋巴瘤细胞表面CD40受体的同源配体结合而启动的。我们的研究表明，CD154在NHL-B细胞中表达的充要条件似乎不同于正常激活的T淋巴细胞，这表明肿瘤淋巴细胞存在基因表达异常和信号通路异常，以介导肿瘤细胞的自主生长。抗CD40或CD154的特异性抗体或反义寡核苷酸可下调NHL-B中NF-kappaB的结构性表达，破坏CD40信号小体的完整性，从而抑制淋巴瘤细胞的生长，并在体外诱导淋巴瘤细胞死亡。在这个计划中，我们将通过分离和测序信号小体中包含的典型的CD40/NFkB通路的组成蛋白来研究CD40信号小体的分子特征，并展示这种大分子结构的信号功能。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与驱动信号体途径密切相关，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抵抗细胞死亡方面的可能作用。除了这些与淋巴瘤细胞增殖和细胞活力有关的异常外，NHL-B细胞还表现出转化生长因子-β/SMAD-SNO/SKI系统的异常表达，这是导致正常B淋巴细胞负生长调节的原因(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该信号系统在NHL-B中的负面调控影响，该信号系统似乎也与NHL-B中的CD40/NFkB系统有关。我们的研究将进一步检测该系统在增强这些淋巴样肿瘤的生物学和可能的临床侵袭性方面的作用，并探索抑制这一途径中的失调元件是否具有治疗潜力。我们相信，我们的CD40信号小体模型将为了解NHL-B所涉及的重要控制机制提供重要的“路线图”，可用于开发这一非常重要的人类淋巴系肿瘤的新治疗方法。