hnRNP U在急性髓系白血病中临床意义及致病机制研究

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.