The Significance of MARCO Expression by Tumor-Pulsed Dendritic Cells

我们以前报道过小鼠肿瘤裂解物致敏的树突状细胞（TP-DC）可以诱导肿瘤特异性的 体外和体内的CD 4+和CD 8 + T细胞反应性。TP-DC治疗可能导致良好的回归- 建立s.c.和肺转移，这可以通过全身施用 低剂量IL-2。虽然已经进行了涉及TP-DC的疫苗研究，但很少有信息（如果有的话）被用于疫苗研究。 肿瘤裂解物的吞噬摄取对DC生物学和功能的影响。我们有 研究了未脉冲的DC和TP-DC之间的基因表达模式差异，使用Affyphase MG- U 74 Av 2寡核苷酸阵列，包含约12，000个基因和EST（表达序列标签）。后 24小时肿瘤裂解物脉冲，87个转录物的水平增加至少三倍，而121个转录物的水平增加至少三倍。 转录物减少三分之一或更多，伴随的p值<0.01。这些基因中的大多数 编码对DC效应子功能重要的蛋白质库，包括细胞因子、趋化因子和 受体，以及抗原呈递、细胞粘附和T细胞活化分子。有意思的是，我们 观察到A类清道夫受体家族的新成员MARCO的高水平表达， 小鼠和人DC。MARCO被认为在免疫反应中发挥重要作用， 介导结合和吞噬作用，而且在形成片状伪足样结构和树突状细胞中也是如此。 流程.我们建议定义TP-DC表达的生物学和潜在的治疗意义， 马可我们假设MARCO表达的调节将对TP-DC产生实质性影响， 在体外和体内的生物学和功能。我们提出以下具体目标：1。以确定影响 MARCO表达调节对TP-DC功能的体外研究; 2.确定MARCO的影响 对TP-DC体内运输的表达调节; 3.确定MARCO的治疗效果 表达调节的TP-DC对小鼠抗肿瘤活性的影响。本次更新中概述的实验研究 应用程序旨在继续我们成功的临床前努力，以产生免疫策略 基于抗原提呈DC的抗肿瘤治疗。这些发现可能对人类有重要的意义。 DC疫苗临床试验

We reported previously that murine tumor lysate-pulsed dendritic cells (TP-DC) could elicit tumor-specific CD4+ and CD8+ T cell reactivities in vitro and in vivo. TP-DC treatments could result in regression of well- established s.c. and lung metastases, which could be further enhanced by the systemic administration of low-dose IL-2. Although vaccine studies involving TP-DC have been performed, little, if any, information is available on the effects of phagocytic uptake of tumor lysate on DC biology and function. We have investigated gene expression pattern differences between unpulsed DC and TP-DC, using Affymetrix MG- U74Av2 oligonucleotide arrays, which contain ~12,000 genes and ESTs (expressed sequence tags). Upon 24 hr tumor lysate pulsing, the levels of 87 transcripts increased at least threefold while the levels of 121 transcripts were reduced by one-third or more, with accompanying p-values <0.01. Most of these genes encoded a repertoire of proteins important for DC effector functions including cytokines, chemokines and receptors, as well as antigen presentation, cell adhesion, and T cell activation molecules. Interestingly, we observed a high level of expression of a novel member of the class A scavenger receptor family, MARCO on both mouse and human DC. MARCO is thought to play an important role in the immune response by mediating binding and phagocytosis, but also in the formation of lamellipodia-like structures and of dendritic processes. We propose to to define the biology and potential therapeutic implication of TP-DC expressed MARCO. We hypothesize that modulation of MARCO expression will have substantial effects on TP-DC biology and function in vitro and in vivo. We propose the following Specific Aims: 1. To determine the effect of MARCO expression modulation on TP-DC function in vitro; 2. To determine the effect of MARCO expression modulation on TP-DC trafficking in vivo; 3. To determine the therapeutic efficacy of MARCO expression-modulated TP-DC on antitumor activity in mice. The experimental studies outlined in this renewal application are designed to continue our successful preclinical efforts to generate immunization strategies against cancer based on antigen-presenting DC. The findings could have significant translation to human clinical DC vaccine trials.