BACKGROUND LncRNA NEAT1 was associated with the tumorigenesis of multiple myeloma (MM). However, the mechanisms of M2 macrophage polarization involved with NEAT1 in MM are still unknown. METHODS Bone marrow samples, multiple myeloma cells RPMI 8226 and monocyte cell line THP-1 were used in this study. The expression of NEAT1 and miR-214 was modified by transfection with the shNEAT1 or miR-214 inhibitor. The expression of NEAT1, miR-214 and B7-H3 in MM patient tissues and cells was analyzed by RT-qPCR. ELISA assay was used to determine the release of B7-H3 in the supernatant of cell culture. The patient survival curve was analyzed using Kaplan-Meier method. The macrophage polarization markers were examined by RT-qPCR and western blotting. The interaction between NEAT1, miR-214 and B7-H3 was analyzed by Dual-Luciferase reporter and RIP assays. AG490 was used to block the JAK2/STAT3 signaling. Co-culture of THP-1 and RPMI 8226 cells was used for macrophage polarization. RESULTS NEAT1 and B7-H3 were up-regulated, but miR-214 was obviously down-regulated in MM patients. B7-H3, NEAT1 and miR-214 were associated with overall survival time of MM patients. NEAT1 silencing induced miR-214 and inhibited the expression and release of B7-H3 and then suppressed M2 macrophage polarization via inhibiting the JAK2/STAT3 signaling. NEAT1 directly targeted miR-214, and miR-214 directly bound to B7-H3. MiR-214 inhibitor reversed the down-regulation and release of B7-H3 and M2 macrophage polarization caused by shNEAT1. The specific JAK2/STAT3 signaling inhibitor AG490 abrogated M2 macrophage polarization. CONCLUSION NEAT1 promoted M2 macrophage polarization by sponging miR-214 and then regulating B7-H3, thus accelerating MM progression via the JAK2/STAT3 signaling pathway. Our study revealed novel mechanisms of M2 macrophage polarization and provided new potential clinical therapeutic targets for MM.

中文翻译：

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LncRNA NEAT1可以通过调节多发性骨髓瘤中的B7-H3来调节miR-214的表达，从而调节M2巨噬细胞的极化。

背景LncRNA NEAT1与多发性骨髓瘤（MM）的肿瘤发生有关。然而，MM中与NEAT1相关的M2巨噬细胞极化的机制仍然未知。方法采用骨髓标本，多发性骨髓瘤细胞RPMI 8226和单核细胞THP-1。通过用shNEAT1或miR-214抑制剂转染可修饰NEAT1和miR-214的表达。通过RT-qPCR分析NEAT1，miR-214和B7-H3在MM患者组织和细胞中的表达。ELISA法用于测定细胞培养上清液中B7-H3的释放。使用Kaplan-Meier方法分析患者的生存曲线。通过RT-qPCR和蛋白质印迹检查巨噬细胞极化标记。NEAT1，miR-214和B7-H3之间的相互作用通过双重荧光素酶报告基因和RIP分析进行了分析。AG490被用来阻止JAK2 / STAT3信号。THP-1和RPMI 8226细胞的共培养用于巨噬细胞极化。结果MM患者中NEAT1和B7-H3上调，而miR-214明显下调。B7-H3，NEAT1和miR-214与MM患者的总生存时间有关。NEAT1沉默诱导miR-214，并抑制B7-H3的表达和释放，然后通过抑制JAK2 / STAT3信号传导抑制M2巨噬细胞极化。NEAT1直接靶向miR-214，而miR-214直接与B7-H3结合。MiR-214抑制剂逆转了由shNEAT1引起的B7-H3和M2巨噬细胞极化的下调和释放。特定的JAK2 / STAT3信号抑制剂AG490废除了M2巨噬细胞极化。结论NEAT1通过使miR-214海绵化然后调节B7-H3来促进M2巨噬细胞极化，因此通过JAK2 / STAT3信号通路加速MM进展。我们的研究揭示了M2巨噬细胞极化的新机制，并为MM提供了新的潜在临床治疗靶标。