Regulation of tumor-supporting monocyte infiltration and macrophage polarization by tumor cell HuR

受mRNA结合蛋白HUR(人类抗原R)调控的转录后事件常常促进肿瘤的恶性。然而，肿瘤HUR对肿瘤微环境的影响，特别是对单核细胞和巨噬细胞的影响，仍然难以捉摸。单核细胞和巨噬细胞是肿瘤间质的重要组成部分。当肿瘤渗入时，单核细胞分化为巨噬细胞，并被培养为肿瘤相关巨噬细胞()表型，这有助于肿瘤的生长。我们推测，HUR在肿瘤细胞中的表达有助于单核细胞对的趋化作用及其极化，从而影响肿瘤的进展。为了研究肿瘤细胞与单核/巨噬细胞之间关于HUR状态的联系，我们使用稳定抑制HUR的肝癌细胞(HepG2)和高表达HUR的细胞。将这些细胞培养成三维肿瘤球体，我们跟踪人单核细胞的渗透，并评估它们对的极化。我们的目的是确定导致单核细胞渗透/极化的HUR依赖因素。为了证明因果关系，我们减弱了这些因子在HepG2细胞中的产生。此外，我们还对有希望的候选基因的Hur依赖调控的分子机制进行了表征。在小鼠肝癌细胞系(HEPA 1-6)中验证了我们的结果后，我们将使用显示转基因HUR状态的肿瘤细胞的同种移植模型在体内测试我们的体外发现。我们的工作增加了对肿瘤细胞中的HUR如何在塑造肿瘤微环境中起作用的理解，即巨噬细胞反应。

Posttranscriptional events regulated by the mRNA binding protein HuR (human antigen R) often promote tumor malignancy. Yet, the impact of tumor HuR on the tumor microenvironment, specifically on monocytes and macrophages, remains elusive. Monocytes and macrophages represent an essential part of the tumor stroma. Upon infiltration of tumors, monocytes differentiate into macrophages and are educated to a tumor-associated macrophages (TAM) phenotype, which contributes to tumor growth. We hypothesize that the expression of HuR in tumor cells contributes to the chemoattractance of monocytes and their polarization towards TAM, thus, affecting tumor progression. To study the communication between tumor cells and monocytes/macrophages with regard to the HuR status in tumor cells we use hepatocellular carcinoma cells (HepG2) with a stable knockdown of HuR vs. cells overexpressing HuR. Culturing these cells as 3D tumor spheroids we follow infiltration of human monocytes and assess their polarization towards TAM. We aim at identifying the HuR-dependent factors that cause monocyte infiltration/polarization. To prove a cause-effect relation we attenuate the production of these factors in HepG2 cells. In addition, we characterize the molecular mechanisms of the HuR-dependent regulation of promising candidates. After verifying our results in a mouse hepatoma cell line (Hepa 1-6), we will use a syngraft model with tumor cells showing a genetically modified HuR status to test our in vitro findings in vivo. Our work increases the understanding how HuR in tumor cells contributes in shaping the tumor microenvironment, i.e. macrophage responses.