分泌型microRNA调控巨噬细胞表型机制及其作为诊断标记物可行性探究

One of the hallmarks of malignancy is the re-education of tumor-associated macrophages(TAM) on its phenotype and function mediated by tumor microenvironment(TME), meanwhile TAM works as a "sustainer" of TME in turn, however, the molecular basis of this process is still unclear. Recently intensive studies suggested secreted microRNAs (miRNAs) to contribute for intercellular communication by a way of horizontal transfer between cells ,then play a role of signal molecule in recipient cell to regulate target gene. Our preliminary data shown many interesting microRNA in TAM which regulate TAM's phenotype by targeting several important transcriptional factors, such as miR-19a-3p. In this study, we are going to detect the abnormal-expressed secreted-microRNAs in the serum of patients with breast cancer, via molecular biology techniques and means, track its transmission path and work on its functional study, further explore the molecular mechanism under the process. We will determine the correlation between secreted microRNAs and tumor development, establish the interation network of secreted microRNA and its target genes in TAM, evaluate the biological significance of secreted microRNA, and provide powerful evidence for it to be a potential clinical diagnostic marker.

肿瘤相关巨噬细胞（TAM）是肿瘤微环境的主要"维持者"，它的表型和功能调控很大程度上影响着肿瘤发展，但有关微环境对它的调控机制还不是很清楚.最近大量报道证实体内血液中的分泌型microRNA作为信号传递分子在细胞之间平行传递，并在受体细胞中发挥内源性microRNA的作用，调节基因表达。我们的前期工作确认了在TAM中一些有趣的microRNA，通过重要的转录因子调控TAM的功能，如miR-19a-3p等。本项目以乳腺癌为疾病模型，通过microRNA芯片检测乳腺癌病人体内由肿瘤组织诱导、异常表达的分泌型microRNA，通过大量分子生物学手段和技术，在体内体外跟踪分泌型microRNA的传输路径，确认它对TAM的表型的调控功能，并探究具体的作用机制。同时，结合大量临床样本，优化检测条件，试图找到分泌型microRNA与肿瘤发展程度的相关性。本项目将通过建立分泌型microRNA及其靶基因对

血清中游离的microRNAs可以作为疾病标志物，本研究通过对194例乳腺癌患者的血清样本进行microRNAs测序，与正常人比较发现miR-1915-3p在病人血清中升高，而miR-455-3p在病人血清中降低。进一步研究发现，与原位癌患者相比，在淋巴结转移和高侵袭性乳腺癌病人的血清中miR-1915-3p的含量更高，而miR-455-3p的含量更低。体外研究发现，miR-1915-3p在多种人乳腺癌细胞系中高表达，并且miR-1915-3p能够通过抑制靶基因DUSP3激活ERK1/1信号通路，从而促进乳腺癌细胞的增殖和迁移能力。以上结果证实，miR-1915-3p与miR-455-3p可以作为乳腺癌临床预后的标志物。.大量研究证实肿瘤相关巨噬细胞能够促进肿瘤的进展，本研究通过对肿瘤相关巨噬细胞中microRNAs测序分析，鉴定出miR-100在肿瘤相关巨噬细胞中高表达，并且miR-100通过直接靶向抑制mTOR来维持其M2的表型。进一步研究发现，miR-100可以通过stat5a/IL-1ra/Hedgehog信号通路来维持肿瘤干细胞的干性特征。更为重要的是，利用miR-100的拮抗剂能够显著提高化疗药顺铂对小鼠乳腺癌的抑制效果。以上结果表明，miR-100可以作为重塑肿瘤免疫微环境的乳腺癌治疗靶标。

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