Inhibitory targeting of HHV-8 vIL-6-related interactions.

描述(申请人提供)：人类疱疹病毒8型(HHV-8)指定白介素6，VIL-6的同系物，它与HHV-8相关的卡波西肉瘤、原发渗出性淋巴瘤(PEL)和多中心Castleman病(MCD)的发生和发展有关。我们已经确定，在PEL细胞中，VIL-6在潜伏期低但有功能地表达；在这种情况下，VIL-6支持细胞的生长和存活，并且这些功能 主要由定位于内质网(ER)的VIL-6介导。因此，VIL-6的内分泌、严格的自分泌信号可能是重要的因素。 在疾病的发病机制中代表着一种独特的细胞因子活性模式。VIL-6在PEL细胞中的这种活性机制尚不清楚，但我们已经确定了VIL-6与一种新的蛋白质-维生素K环氧化物还原酶复合体亚基1变体-2(VKORC1v2)在功能上的重要相互作用，最近还确定了IL-6信号转导系统gp130对PEL细胞的持续生长是必不可少的。此外，我们还发现了VKORC1v2与硫氧还蛋白还原酶样蛋白1(TMX1)、蛋白二硫键异构酶A6/P5(PDI-A6)和组织蛋白酶D(CatD)的相互作用，提示VKORC1v2可能具有与VIL-6折叠有关的功能和/或VIL-6通过VKORC1v2相互作用影响ER应激反应或CatD加工以及相关的促增殖和凋亡信号调节。在这个R21应用中，我们建议识别和测试VIL-6的PEL抑制肽和小分子抑制剂：VKORC1v2相互作用和功能上的VIL-6：gp130络合；我们还将评估有效的抑制剂对VKORC1v2与其新发现的细胞相互作用伙伴相互作用所预测的功能的影响。因此，这项工作扩展了我们在PEL背景下VIL-6与VKORC1v2和gp130相互作用的功能表征，并解决了针对这些具有生物重要性的病毒-宿主相互作用的分子策略。该项目对未来基于药物的治疗该肿瘤以及可能与HHV-8相关的其他恶性肿瘤的发展具有重要意义，而VIL-6可能在其中发挥关键作用。

DESCRIPTION (provided by applicant): Human herpesvirus 8 (HHV-8) specifies a homologue of interleukin-6, vIL-6, which is implicated in the development and progression of HHV-8-associated Kaposi's sarcoma, primary effusion lymphoma (PEL), and multicentric Castleman's disease (MCD). We have determined that in PEL cells vIL-6 is expressed at low but functional levels during latency; vIL-6 in this setting supports cell growth and survival, and these functions are mediated predominantly intracellularly by vIL-6 localized in the endoplasmic reticulum (ER). Thus, intracrine, strictly autocrine signaling by vIL-6 is likely to be an important contributor to PEL disease and represents a unique mode of cytokine activity in disease pathogenesis. The mechanisms underlying this activity of vIL-6 in PEL cells is not understood, but we have identified a functionally important interaction of vIL-6 with a novel protein, vitamin K epoxide reductase complex subunit 1 variant-2 (VKORC1v2), and also have recently determined that the IL-6 signal transducer, gp130, is essential for sustained growth of PEL cells. Additionally, we have identified interactions of VKORC1v2 with thioredoxin reductase-like protein 1 (TMX1), protein disulfide isomerase A6/P5 (PDI-A6) and cathepsin D (catD) that suggest possible functions of VKORC1v2 related to vIL-6 folding and/or influence of vIL-6, via VKORC1v2 interaction, on ER stress responses or on catD processing and associated regulation of pro-proliferative and apoptotic signaling. In this R21 application, we propose to identify and test in respect of PEL inhibition peptide and small molecule inhibitors of vIL- 6:VKORC1v2 interaction and functional vIL-6:gp130 complexing; we will also assess the effects of validated inhibitors on functions predicted from interaction of VKORC1v2 with its newly identified cellular interaction partners. The work therefore extends our functional characterization of vIL-6 interactions with VKORC1v2 and gp130 in the context of PEL and addresses molecular strategies to target these biologically important virus- host interactions. The project has substantial significance to the future development of drug-based therapies for this and possibly other HHV-8-associated malignancies in which vIL-6 is likely to play a critical role.