Targeted inhibition of microRNA-21 with antisense oligonucleotide and their effects on human leukemic K562 cells

AIM: To explore the inhibitory effect of anti-miRNA-21 oligonucleotide(AMO-miRNA-21) on human leukemic K562 cells.METHODS: K562 cells were transfected with AMO-miRNA-21,which was complementary to the miRNA-21 in a sequence-specific manner.Viability of K562 cells was measured by MTT assay and the optimal concentration for transfection was determined.The inhibitory effect of AMO on the K562 cell growth was examined by trypan blue dye exclusion assay at 24 h,48 h and 72 h after transfection.Giemsa's staining was used to detect morphologic changes of the transfected cells.The cell apoptosis and cell cycle progression were assayed by flow cytometry.Expression of microRNA-21 in the cells was measured by real-time PCR.RESULTS: The growth of cells treated with AMO-miRNA-21 was obviously inhibited compared with that in control groups(P0.05).Very low cytotoxic and high inhibitory effects of AMO-miRNA-21 were found at concentration of 0.6 μmol/L.The inhibitory effect lasted for 72 h.Apoptotic cells were increased in AMO group and typical morphologic changes were conformed by Giemsa's staining.One visible hypodiploid peak was detected in the histogram.However,the cell cycle progression was not inhibited evidently.The expression of microRNA-21 in the transfected cells was down-regulated significantly.CONCLUSION: Targeted inhibition of microRNA-21 with antisense oligonucleotide effectively suppresses leukemic K562 cells growth by inducing apoptosis.miRNA-21 might be a potential target for leukemia therapy.