非编码RNA调控巨噬细胞PTPROt基因在肝癌转移中的作用及机制研究

It is well accepted that metastasis can be enhanced due to immunosuppressive tumor microenvironment. Immunocytes especially alternative activated macrophage (M2) played pivot roles in modulating tumor microenvironment. Cell signaling networks mediating M2 and its downstream effectors were gradually unmasked. However, the knowledge on its upstream signaling was still remained unknown. Our proposal was based on a possible feedback loop within tumor microenvironment composed by Lnc-PTPRO-miR-27a-3p-PTPROt predicted by using genomics analysis and co-expression analysis. Decreased Lnc-PTPRO can enhance the effect of miR-27a-3p, and thus to silence PTPROt expression in macrophage, increasing the differentiation of M2, and finally promoting metastasis of liver cancer by immunosuppressive microenvironment. The project will confirm the existence and mechanism of Lnc-PTPROt-miR-27a-3p-PTPROt loop, meanwhile to explore the PTPROt related cell signaling mediating M2 differentiation, also to investigate the modulation on Lnc-PTPRO by such cell signaling. And finally to setup an experimental therapeutic model of liver cancer metastasis. The project can will enrich our knowledge on the roles of non-coding RNA in tumor microenvironment and to lay theoretical and experimental basis of diagnosis and treatment of liver cancer metastasis.

抑制性肿瘤微环境促进肿瘤转移正成为国际公认的理论，其中的免疫细胞特别是替代途径激活的巨噬细胞（M2）在调节免疫环境中起核心作用。其调控细胞信号网络及下游效应因子正日益明晰，但对其上游调控途径仍知之甚少。本项目前期研究通过组学检测及共表达分析，预测肝癌巨噬细胞中可能存在的Lnc-PTPRO-miR-27a-3p-PTPROt反馈环，在微环境中由于Lnc-PTPRO的下调释放miR-27a-3p从而沉默巨噬细胞中PTPROt基因，导致巨噬细胞向M2分化，诱发肝癌内抑制性免疫环境并促进肝癌的转移。本项目拟从临床标本入手，在证实该反馈环的基础上，通过体内及体外研究找寻PTPROt基因调控M2分化的信号通路网络，探讨该网络对于非编码基因Lnc-PTPRO的调控，再利用已阐明的机制构建实验性肝癌转移治疗模型。为完善非编码RNA在肿瘤微环境中的作用，从肝癌肿瘤微环境入手诊治肝癌转移提供理论及实验依据。

背景:我们之前已经发现了蛋白酪氨酸磷酸酶O型受体(PTPRO)在肿瘤浸润T细胞中的低表达，且与免疫抑制相关。本研究的目的是探讨人肝癌(HCC)外周血单核细胞和肿瘤浸润巨噬细胞中PTPRO减少与程序性死亡配体1 (PD-L1)增加之间的关系。.方法:探讨单核细胞和肿瘤浸润巨噬细胞中各项指标的表达及相关性。通过体内外实验研究了其机制。.结果:我们发现在HCC外周血单核细胞中PTPRO明显减少，这与外周血单核细胞和肿瘤相关巨噬细胞中PD-L1表达增加有关。单核细胞PD-L1和PTPRO可作为肝癌术后患者有价值的预后指标，并与T细胞衰竭(Tim3+ T细胞)增加有关。PTPRO的缺失通过JAK2/STAT1和JAK2/STAT3/c-MYC通路促进单核细胞和巨噬细胞的PD-L1分泌。IL-6表达升高与JAK2/STAT3/c-MYC的活化有关，通过STAT3/c-MYC/miR-25-3p轴降低PTPRO表达。单核细胞和巨噬细胞中miR-25-3p的表达明显增加，可以靶向PTPRO的3'UTR区域。在HCC单核细胞中，miR-25-3p表达水平与血清IL-6水平呈正相关，与PTPRO呈负相关。IL-6/STAT3/c-MYC的激活增强了体外miR-25-3p的转录，降低了PTPRO，进一步促进了PD-L1的分泌。.结论:血清IL-6通过激活STAT3/c-MYC/miR-25-3p，并通过JAK2/STAT1和JAK2/STAT3/c-MYC信号通路进一步上调PD-L1的表达，从而降低了HCC单核细胞和巨噬细胞中PTPRO的表达。