microRNA参与肿瘤前转移微环境形成的分子机制

发布时间：2018-05-15 23:10

  本文选题：前转移微环境 + miR-30s　； 参考：《清华大学》2015年博士论文

【摘要】：肿瘤转移已成为实体肿瘤患者死亡的主要诱因。肿瘤的转移过程十分复杂,主要步骤包括:肿瘤细胞从原发瘤侵入血管进入血液循环,随后侵出血管进入转移靶器官,最终形成转移灶。实际上,在肿瘤细胞尚未发生转移前,原发瘤已经对转移靶器官产生影响,促使靶器官形成一个可以支持肿瘤转移和生长的微环境,称之为“前转移微环境”。前转移微环境的形成需要原发瘤来源的分泌因子与转移靶器官之间的相互作用,目前,已经对原发瘤来源的分泌因子进行了大量研究,但是关于转移靶器官对前转移微环境形成的作用机制尚不清楚。鉴于miRNAs在肿瘤发生和发展过程中发挥了重要作用,本文系统地研究了转移靶器官miRNAs参与肿瘤前转移微环境形成的分子机制。首先,在B16/F10黑色素瘤诱导的前转移肺微环境模型中,通过miRNAs芯片筛选出在前转移肺微环境形成过程中表达水平显著下调的miRNAs:miR-30a、30b、30c、30d和30e(miR-30s),随后研究发现主要是肺成纤维细胞miR-30s的表达量发生了下调。肺成纤维细胞的miR-30s抑制了前转移肺组织血管内皮生长因子受体1+(VEGFR1+)骨髓来源细胞的招募,并降低了肺组织血管的通透性。由于骨髓来源细胞的招募和血管通透性的上升是前转移微环境形成的主要特征,所以上述结果表明,miR-30s可以抑制前转移肺微环境的形成。在小鼠肺组织中过表达miR-30s,可以显著地抑制肿瘤的肺转移并延长荷瘤鼠的生存期。随后,通过一系列的生物信息学分析和体内外实验筛选策略,我们鉴定出与肿瘤前转移肺微环境形成相关的miR-30s靶基因:Klf9、Nedd4l、Rab38、Skp2和Ugt8a。在前转移肺微环境中,这5个靶基因的表达水平显著上调。进一步研究发现,Rab38通过调节CCL2、CXCL1和VEGFA的分泌促进了VEGFR1+骨髓来源细胞向前转移肺组织的招募和聚集,而Skp2则通过上调基质金属蛋白酶9(MMP9)的表达提高肺组织的血管通透性。在小鼠肺组织中分别过表达Rab38和Skp2均显著地促进了肿瘤的肺转移并缩短荷瘤鼠的生存期。本研究阐明了转移靶器官的miRNAs参与肿瘤前转移微环境形成的新的分子机制,同时深入理解前转移微环境的形成过程,为靶向肿瘤转移的临床应用提供了新的思路。
[Abstract]:Tumor metastasis has become the main cause of death in patients with solid tumors. The process of tumor metastasis is very complicated. The main steps include: tumor cells invade the blood vessels from the primary tumor into the blood circulation, then invade the blood vessels and enter the target organs and eventually form the metastasis. In fact, the primary tumor has been transferred before the tumor cells have been transferred. The effect of the target organ, which causes the target organ to form a microenvironment that can support tumor metastasis and growth, is called the "anterior transfer microenvironment". The formation of the anterior metastatic microenvironment requires the interaction between the secretory factor of the primary tumor source and the target organ of the metastatic target. However, the mechanism of the transfer of target organs to the formation of the anterior metastatic microenvironment is still unclear. In view of the important role of miRNAs in the development and development of tumor, this paper systematically studies the molecular mechanism of the transfer of target organ miRNAs in the formation of pre tumor microenvironment. First, the pre metastasis of B16/F10 melanoma induced by melanoma. In the lung microenvironment model, miRNAs:miR-30a, 30b, 30C, 30d and 30e (miR-30s) were significantly downregulated during the formation of the anterior metastatic lung microenvironment by miRNAs chip. The subsequent study found that the expression of miR-30s in lung fibroblasts was downregulated. Pulmonary fibroblast cell miR-30s inhibited the anterior metastatic pulmonary tissue. The recruitment of bone marrow derived cells from endothelial growth factor receptor 1+ (VEGFR1+) and reducing the permeability of pulmonary tissue. As the recruitment of bone marrow cells and the increase of vascular permeability are the main characteristics of the formation of the anterior metastatic microenvironment, the above results suggest that miR-30s can inhibit the formation of the anterior metastatic lung microenvironment. MiR-30s can significantly inhibit the lung metastasis of tumor and prolong the survival period of the tumor bearing mice. Then, through a series of bioinformatics analysis and in vivo and in vivo screening strategies, we identified the miR-30s target genes related to the formation of pre tumor metastasis lung microenvironment: Klf9, Nedd4l, Rab38, Skp2 and Ugt8a. in the anterior metastatic lung microenvironment The expression level of these 5 target genes is significantly up-regulated. Further studies have found that Rab38 promotes the recruitment and aggregation of forward metastatic lung tissue in VEGFR1+ bone marrow cells by regulating CCL2, CXCL1 and VEGFA, while Skp2 increases the vascular permeability of lung tissue by increasing the expression of matrix metalloproteinase 9 (MMP9). In mice lung tissue The overexpression of Rab38 and Skp2 respectively promoted the lung metastasis of tumor and shortened the survival time of the tumor bearing mice. This study clarified the new molecular mechanism that the miRNAs of the metastatic target organs was involved in the formation of the pre tumor microenvironment, and the formation process of the anterior metastatic microenvironment was deeply understood, which provided the clinical application of the target tumor metastasis. A new idea.

【学位授予单位】：清华大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：R73-37
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本文编号：1894361