miR-181a在急性淋巴细胞白血病患儿中的表达及其功能研究

OBJECTIVE: To investigate the expression of miR-181a in bone marrow (BM) samples of pediatric acute lymphoblastic leukemia (ALL) and explore the mechanism of miR-181a on ALL cell line CCRF-CEM and drug resistance cell line CEM-C1. METHODS: BM samples were obtained from 18 patients where matched samples at initial diagnosis and first BM relapse or complete remission were available. BM samples and cord blood samples (normal controls) were used to confirm the differential expression of miRNA-181a by quantitative real-time polymerase chain reaction (qRT-PCR). The expressions of miR-181a in both CCRF-CEM and its mutidrug-resistant counterpart CEM-C1 cells were also detected. Then, CCK-8 assay was performed to quantify the effects of miR-181a on CEM-C1 and CCRF-CEM cells growth and viability. RESULTS: Up-regulated miR-181a with higher fold changes in both initial diagnosis (4.84±2.71, 7.58±2.50) and relapsed samples (6.53±2.20) compared to normal controls(1.41±0.53) (P=0.017, 0.000, 0.001, respectively) were observed, whereas the miR-181a expression in the samples of CR (1.35±0.35) compared to normal control showed no significant difference (P=0.863). The miR-181a expression level was higher in CEM-C1 cells (−4.39±0.08) than of in CCRF-CEM cells (−2.32 ± 0.03) (P=0.000). CCK-8 assay revealed that suppression of miR-181a in CEM-C1 cells by transfecting the specific inhibitor of miR-181a led to significantly higher cellular proliferation inhibition rate than negative control cells (P<0.05), IC(50) were 30.61 ng/ml and 2 255.00 ng/ml with RI as 73.67. While increased miR-181a in CCRF-CEM cells led to significantly lower CPIR than negative control cells (P<0.01), IC(50) were 126.60 ng/ml and 1.34 ng/ml with RI as 94.26. CONCLUSION: Upregulation of miR-181a might play an important role in the development of drug resistance in CEM-C1 cells, and knockdown of miR-181a could sensitize CEM-C1 cells to camptothecin; Meanwhile increased expression of miR-181a could promote CCRF-CEM drug resistance. These results suggested that suppression of miR-181a expression might provide a promising therapeutic in drug resistance of leukaemia.