Conclusion
In this study, we found that the inducible expression of PR downregulates IRF9 and can be reversed by ATRA, suggesting a specific regulatory relationship between IRF9 and the PR fusion gene. The induction of IRF9 expression in NB4 cells can promote cell differentiation as well as reduce the colony forming ability of leukemia cells, implying an anti-leukemia effect for IRF9, which lays a biological foundation for IRF9 as a potential target for the treatment of APL. 目的： 研究急性早幼粒细胞白血病（APL）中干扰素调节因子9（IRF9）的表达特征、预后意义和生物学功能，探索IRF9作为潜在治疗靶点的临床转化意义。 方法： 挖掘TCGA公共数据分析IRF9在APL中的表达水平及其表达高低对患者生存的影响；利用Dox诱导的慢病毒载体系统构建可诱导表达PML-RARα（PR）融合基因的U937细胞系，诱导PR融合基因早期表达并加入全反式维甲酸（ATRA）检测IRF9表达变化；构建可诱导表达IRF9的NB4细胞系，进行细胞分化和集落形成实验，初步探讨IRF9诱导表达对NB4白血病细胞生物学功能的影响。 结果： ①TCGA数据库分析显示，在各种类型的AML中，IRF9在APL中表达水平最低且与预后不良相关。②成功构建可诱导表达PR融合基因的U937细胞系；PR表达引起IRF9蛋白水平下调，在NB4细胞系中IRF9表达缺失，ATRA处理后可表达上调。③成功构建可诱导表达IRF9的NB4细胞系，IRF9诱导表达促进NB4细胞的分化，且与较低剂量ATRA有协同促分化作用；IRF9诱导表达显著抑制了NB4细胞的集落形成能力。 结论： IRF9在APL中低表达且与预后不良相关，提示存在特异性调控机制；上调IRF9表达可发挥抗白血病效应，为其成为临床潜在治疗靶点奠定生物学基础。.
Methods
The gene expression profile and survival data applied in the bioinformatic analysis were obtained from The Cancer Genome Atlas and Beat acute myeloid leukemia (AML) cohorts. A dox-induced lentiviral system was used to induce the expression of PML-RARα (PR) in U937 cells, and the expression level of IRF9 in U937 cells treated with or without ATRA was examined. We then induced the expression of IRF9 in NB4, a promyelocytic leukemia cell line. In vitro studies focused on leukemic phenotypes triggered by IRF9 expression.
Objective
To investigate the prognostic significance of interferon regulatory factor 9 (IRF9) expression and identify its role as a potential therapeutic target in acute promyelocytic leukemia (APL) .
Results
①Bioinformatic analysis of the public database demonstrated the lowest expression of IRF9 in APL among all subtypes of AML, with lower expression associated with worse prognosis. ②We successfully established a PR-expression-inducible U937 cell line and found that IRF9 was downregulated by the PR fusion gene in APL, with undetectable expression in NB4 promyelocytic cells. ③An IRF9-inducible NB4 cell line was successfully established. The inducible expression of IRF9 promoted the differentiation of NB4 cells and had a synergistic effect with lower doses of ATRA. In addition, the inducible expression of IRF9 significantly reduced the colony formation capacity of NB4 cells.