Huang Yingdan, Hong Xiuli, Hu Jiasheng, Lu Quanyi
Department of Blood Transfusion, The First Affiliated Hospital of Xiamen University.
Department of Hematology, Zhongshan Hospital of Xiamen University, Xiamen, People's Republic of China.
Onco Targets Ther. 2017 Jun 29;10:3233-3239. doi: 10.2147/OTT.S126819. eCollection 2017.
miRNA is a microRNA that negatively regulates protein expression at post-transcriptional or translational level. It is widely involved in the pathogenesis of tumors. miR-98 belongs to the let-7 family, and its overexpression can increase the sensitivity to drugs in solid cancer cells. However, the function of miR-98 in leukemia is still unclear. In this study, the effect of miR-98 on drug resistance and proliferation of leukemia cells were investigated.
Real-time quantitative polymerase chain reaction analyzed the expression difference between miR-98 and E2F1 in leukemia cell lines, K562 and K562/A02. The downstream target gene of miR-98 was predicted by TargetScan; K562/A02 was transiently transfected with miR-98 mimic to upregulate the expression of miR-98; real-time quantitative polymerase chain reaction and Western blot were used to analyze the expression alterations of E2F1; cell counting kit-8 was used to evaluate the influence on K562/A02 proliferation and sensitivity to chemotherapeutic drugs; meanwhile, Western blot was used to analyze the expression of p21, Bax, matrix metalloproteinase 9 and ABCG2 proteins.
E2F1 is one of the target genes of miR-98 proved by bioinformatics. Compared with the K562, the level of miRNA-98 expression was decreased in K562/A02, but the level of E2F1 expression was upregulated. Leukemia cell line K562/A02 was transfected with miR-98 mimic to upregulate the expression of miR-98, the expression of E2F1 was significantly decreased. After upregulating the miR-98 expression in K562/A02, the proliferation was weakened, and the sensitivity to chemotherapy was increased. Western blot showed that upregulated miR-98 expression increased the levels of p21 and BAX proteins in K562/A02 cells, and decreased the levels of matrix metalloprotease 9 and ABCG2 proteins, which were significantly different compared with those before miR-98 mimic transfection.
In the leukemia drug-resistant cell line K562/A02, the targeted upregulated expression of miR-98 could decrease the proliferation of leukemia cells and improve the sensitivity to chemotherapeutics by inhibiting E2F1 expression. miR-98 might be a potential target for overcoming leukemia multidrug resistance.
微小RNA（miRNA）是一种在转录后或翻译水平负向调节蛋白质表达的小分子RNA。它广泛参与肿瘤的发病机制。miR-98属于let-7家族，其过表达可增加实体癌细胞对药物的敏感性。然而，miR-98在白血病中的功能仍不清楚。本研究探讨了miR-98对白血病细胞耐药性和增殖的影响。
采用实时定量聚合酶链反应分析白血病细胞系K562和K562/A02中miR-98与E2F1的表达差异。通过TargetScan预测miR-98的下游靶基因；用miR-98模拟物瞬时转染K562/A02以上调miR-98的表达；采用实时定量聚合酶链反应和蛋白质免疫印迹法分析E2F1的表达变化；用细胞计数试剂盒-8评估对K562/A02增殖及对化疗药物敏感性的影响；同时，用蛋白质免疫印迹法分析p21、Bax、基质金属蛋白酶9和ABCG2蛋白的表达。
生物信息学证明E2F1是miR-98的靶基因之一。与K562相比，K562/A02中miRNA-98表达水平降低，但E2F1表达水平上调。用miR-98模拟物转染白血病细胞系K562/A02以上调miR-98的表达，E2F1的表达明显降低。上调K562/A02中miR-98的表达后，其增殖减弱，对化疗的敏感性增加。蛋白质免疫印迹显示，上调miR-98表达可增加K562/A02细胞中p21和BAX蛋白的水平，降低基质金属蛋白酶9和ABCG2蛋白的水平，与转染miR-98模拟物前相比有显著差异。
在白血病耐药细胞系K562/A02中，靶向上调miR-98的表达可通过抑制E2F1的表达降低白血病细胞的增殖并提高对化疗药物的敏感性。miR-98可能是克服白血病多药耐药的潜在靶点。
