PIM1基因对急性髓系白血病U937细胞增殖、凋亡及JAK2/STAT3信号通路的影响

Effects of PIM1 Gene on Proliferation,Apoptosis and JAK2/STAT3 Signaling Pathway of Acute Myeloid Leukemia U937 Cells

目的:探讨PIM1基因对急性髓系白血病(AML)U937细胞增殖、凋亡的影响,以及对JAK2/STAT3通路的调控作用。方法:收集初诊成人AML患者和单纯缺铁性贫血患者的骨髓单个核细胞,荧光定量PCR检测PIM1 mRNA表达。将AML细胞系U937细胞分为:U937组(U937细胞正常培养)、Si-PIM1组(U937细胞转染含PIM1 mRNA的低表达腺病毒载体)、Si-NC组(U937细胞转染不含PIM1 mRNA的低表达腺病毒载体)、CoA1组(U937细胞中加入浓度为20μmol/L的JAK2激活剂CoA1)、Si-PIM1+CoA1组(U937细胞转染含PIM1 mRNA低表达的腺病毒载体并加入浓度为20μmol/L的CoA1)。培养24 h。荧光定量PCR和蛋白印迹法检测U937细胞PIM1 mRNA和蛋白、JAK2/STAT3通路、细胞周期、凋亡相关蛋白表达;噻唑蓝法检测细胞增殖活性;流式细胞术检测细胞周期变化及凋亡率。结果:AML患者骨髓单个核细胞中PIM1 mRNA表达水平高于单纯缺铁性贫血患者(P<0.05)。与U937组相比,Si-PIM1组细胞PIM1 mRNA和蛋白、p-JAK2/JAK2、p-STAT3/STAT3、Cyclin D1、CDK2蛋白、细胞增殖活性、S期比例、G2/M期比例降低(均P<0.05),p27、Caspase-3蛋白、G0/G1期、凋亡率升高(均P<0.05),而CoA1组上述指标的变化情况与Si-PIM1组正好相反,CoA1可逆转Si-PIM1对U937细胞的作用效果。U937组、Si-PIM1+CoA1组、Si-NC组U937细胞上述指标差异无统计学意义(P>0.05)。结论:敲低PIM1基因表达可抑制U937细胞增殖、促进凋亡,缓解ALM进程,且上述作用可能与抑制JAK2/STAT3通路活化有关。

Objective:To investigate the effects of the serine/threonine kinase family member 1(PIM1)gene on the proliferation and apoptosis of acute myeloid leukemia(AML)U937 cells,and the regulation effect on Janus kinase 2(JAK2)/signal transducer and activator of transcription 3(STAT3)pathway.Methods:Bone marrow mononuclear cells from newly diagnosed adult AML patients and patients with iron deficiency anemia were collected and PIM1 mRNA expression was detected by RT-qPCR.AML cell line U937 cells were divided into U937 group(U937 cells were cultured normally),Si-PIM1 group(U937 cells were transfected with low expression adenovirus vector containing PIM1 mRNA),Si-NC group(U937 cells were transfected with low expression adenovirus vector without PIM1 mRNA),coumermycin A1(CoA1)group(JAK2 activator CoA1 was added to U937 cells at a concentration of 20μmol/L),and Si-PIM1+CoA1 group(U937 cells were transfected with adenoviral vector containing low expression of PIM1 mRNA and added with CoA1 at a concentration of 20μmol/L).After culture for 24 h,the expressions of PIM1 mRNA and protein,JAK2/STAT3 pathway,cell cycle and apoptosis-related proteins in U937 cells were detected by RT-qPCR and Western blot,the cell proliferation activity was detected by MTT assay,and flow cytometry was used to detect cell cycle changes and apoptosis rate.Results:The PIM1 mRNA expression level in bone marrow mononuclear cells in AML patients was higher than that in patients with iron deficiency anemia(P<0.05).Compared with U937 group,PIM1 mRNA and protein,phosphorylated JAK2(p-JAK2)/JAK2,phosphorylated STAT3(p-STAT3)/STAT3,Cyclin D1,cyclin-dependent kinase 2(CDK2)protein,cell proliferation activity,S phase and G2/M phase proportions were decreased in Si-PIM1 group(all P<0.05),while p27,Caspase-3 protein,G0/G1 phase proportion and apoptosis rate were increased(all P<0.05).However,the changes of above indicators in CoA1 group were just opposite to those in Si-PIM1 group,indicating that CoA1 could reverse the effect of Si-PIM1 on U937 cells.There were no significant differences in above indexes of U937 cells between U937 group,Si-PIM1+CoA1 group and Si-NC group(P>0.05).Conclusion:Knockdown of PIM1 gene expression can inhibit U937 cell proliferation and promote apoptosis,in order to alleviate ALM process,which may be related to the inhibition of JAK2/STAT3 pathway activation.