Objective: To investigate the clinical significance and pathogenesis of heterogeneous nuclear ribonucleoprotein U (hnRNP U) in acute myeloid leukemia (AML) . Methods: The expression of hnRNP U, an RNA binding protein, in patients with AML and healthy controls was compared based on the Gene Expression Profiling Interactive Analysis database and the data of the center. The Beat AML Dataset (n=158) was downloaded from the cBioPortal database. The hnRNP U expression level was divided into the high-expression group (n=89) and low-expression group (n=69) , and patients\' clinical characteristics were compared. The effect of hnRNP U on the biological behavior of human AML cell lines was studied by Cell Counting Kit-8 assay to detect cell proliferation. Annexin Ⅴ-APC/7-AAD antibodies were used to detect cell apoptosis. DNA content (PI staining) was quantitatively analyzed to detect cell cycle changes, and colony formation experiments were performed to detect cell cloning formation ability after hnRNP U knockdown in Kasumi-1 and MOLM-13 cells. To study the effect of hnRNP U knockdown on the DNA damage response (DDR) pathway proteins of cleaved-PARP, immunoblot analysis using p-H2A.X was conducted. Results: ①Pan-cancer analysis showed that hnRNP U was highly expressed in patients with AML, and the expression level of hnRNP U mRNA in peripheral blood mononuclear cells was significantly higher in patients with AML than in healthy controls (0.0315±0.0042 vs 0.0195±0.0006, respectively, P<0.01) . ②The age of onset was 56 (2-87) years in the high-expression group and 65 (8-85) years in the low-expression group (t=-2.681, P=0.007) . Moreover, the high-expression group had a higher proportion of combined FLT3 mutations than the low-expression group (χ(2)=4.069, P=0.044) . ③Compared with the negative control, hnRNP U knockdown inhibited the proliferation (P<0.001 and P<0.001) , promoted the apoptosis (P<0.01 and P<0.001) , decreased the colony formation ability (P<0.001 and P<0.001) , and arrested the cell cycles in the G(2)/M phase (P<0.05 and P<0.01) of Kasumi-1 and MOLM-13 cells, respectively. ④hnRNP U knockdown could increase the protein expression of cleaved-PARP and p-H2A.X on the DDR pathway. Conclusion: hnRNP U is highly expressed in AML, and hnRNP U knockdown can inhibit the occurrence and development of AML possibly through the activation of the DDR pathway.
目的: 研究RNA结合蛋白核不均一核糖核蛋白U(hnRNP U)在急性髓系白血病(AML)中临床意义及致病机制。 方法: 基于数据库(GEPIA)和本中心数据比较hnRNP U在AML患者及健康对照者中表达情况;通过Cbioportal数据库下载Beat AML数据集(158例),按照hnRNP U表达水平分为高表达组(89例)和低表达组(69例)并对两组临床特征进行比较;选择hnRNP U高表达的Kasumi-1和MOLM-13细胞系,敲低hnRNP U后通过CCK-8检测细胞增殖能力,利用Annexin Ⅴ-APC/7-AAD抗体检测细胞凋亡情况,通过定量分析DNA含量(PI染色)检测细胞周期变化及克隆形成实验检测细胞集落形成能力等方面研究hnRNP U对人AML细胞系生物学行为的影响;利用Western blot法研究敲低hnRNP U后对DDR(DNA Damage Response)通路蛋白cleaved-PARP、p-H2A.X表达的影响。 结果: ①泛癌分析发现hnRNP U在AML中高表达,AML患者外周血单个核细胞中hnRNP U mRNA表达水平显著高于健康对照者(0.0315±0.0042对0.0195±0.0006,P<0.01);②hnRNP U高表达组中位发病年龄为56(2~87)岁,hnRNP U低表达组中位发病年龄为65(8~85)岁,hnRNP U高表达组较低表达组发病年龄更早(t=-2.681,P=0.007),且合并FLT3突变比例更高(χ(2)=4.069,P=0.044);③敲低hnRNP U后Kasumi-1、MOLM-13细胞增殖受抑,细胞凋亡率增高,集落形成能力减弱,细胞周期阻滞在G(2)/M期,与对照组比较,差异均有统计学意义(P值均<0.05);④敲低hnRNP U可引起DDR通路上cleaved-PARP、p-H2A.X蛋白表达上调。 结论: hnRNP U在AML中高表达,敲低hnRNP U后可抑制AML的发生发展,其可能是通过激活DDR通路发挥作用。.