lung tumor exosome-mediated inflammation promotes tumor progression and growth

这项建议的总体目标是阐明肺肿瘤外切体促进炎症反应的机制，即巨噬细胞的激活，并促进肺肿瘤的进展和生长。我们的初步数据表明，用TC-1肺癌细胞产生的外切体预处理A/J小鼠，或从NJ小鼠的肺组织中分离出经乌拉坦预处理的外切体会导致更快的肿瘤生长和更早的肺癌进展。乌拉坦治疗导致激活形式的TRAF2重新聚集到外切体，具有激活TRAF2的外切体被巨噬细胞的骨髓源前体摄取，导致它们成熟并随后迁移到肺。激活的TRAF2募集到外体需要肿瘤细胞中炎症抑制蛋白CyLD的降解，而且TRAF2可以介导CyLD的泛素化，从而促进其降解。然而，siRNA TRAF2基因敲除的结果表明，TRAF2是CyLD泛素化所必需的，但不足以实现泛素化。我们现在已经确定了两种与TRAF2相互作用的外体蛋白，Itch和Jabi，它们有可能增强肺癌细胞中CyLD的泛素化。我们建议：(1)通过确定TRAF2在TC-1肺癌细胞中的敲除是否足以(0)抑制巨噬细胞分化和(Ii)阻止TC-1细胞外切体介导的促进乌拉坦诱导的肺癌，来证实肺癌外体TRAF2在乌拉坦诱导的肺癌中的促进作用。(2)检测TC-1外切体中的JABI和ITCH是否具有促进CD11bGr1细胞向活化巨噬细胞分化的作用。(3)外切体靶向体内细胞的鉴定。所产生的数据应该允许开发一种高度创新的细胞和分子基础模型，用于外切体介导的慢性炎症和促进肺癌生长，并提出新的预防和治疗策略。

The overall goal of this proposal is to elucidate the mechanisms by which lung tumor exosomes promote an inflammatory response, namely the activation of macrophages, and promote the progression and growth of lung tumors. Our preliminary data indicate that pretreatment of A/J mice with exosomes produced by TC-1 lung tumor cells or exosomes isolated from the lung tissue of NJ mice that have been pretreated with the carcinogen urethane results in more rapid tumor growth and earlier progression of lung carcinomas. Urethane treatment results in the recruitment of the activated form of TRAF2 to the exosomes, and the exosomes with activated TRAF2 are taken up by the bone marrow-derived precursors of macrophages, leading to their maturation and subsequent migration to the lung. The recruitment of the activated TRAF2 to the exosomes requires degradation of the inflammation suppressor protein, CYLD, in the tumor cells; moreover, TRAF2 can mediate ubiquitination of CYLD thereby promoting its degradation. The results of siRNA TRAF2 knockout indicated, however, that TRAF2 is required but is not sufficient for ubiquitination of CYLD. We have now identified two exosomal proteins that interact with TRAF2, Itch and Jabi, which have the potential to enhance the ubiquitination of CYLD in lung tumor cells. We propose to: (1) Confirm the role of lung tumor exosomal TRAF2 in the promotion of urethane-induced lung carcinomas by determining whether knockout of TRAF2 in TC-1 lung tumor cells is sufficient for (0 inhibition of macrophage differentiation and (ii) prevention of TC-1 cell exosome-mediated enhancement of urethane induced lung cancer. (2) Determine if Jabi and itch in the TC-1 exosomes are capable of promoting the differentiation of CD1 1bGr1 cells into activated macrophages. (3) Identification of cells targeted in vivo by exosomes. The data generated should permit the development a highly innovative model of the cellular and molecular basis for exosome-mediated chronic inflammation and promotion of lung tumor growth and suggest novel preventive and therapeutic strategies.