The effect of antisense bcr-abl oligonucleotides on the growth of K562 cells

AIM:To study the effect of bcr- abl gene antisense phosphorothioate oligonucleotides(Aspo) on K562 cell line and explore its significance in chrenic myelogeneous leukemia (CML) gene therapy.METHODS:Cells were exposed to oligomeis, observed by inverted microscope.Cells inhibitory rate were determined by 0.4 trypan blue exclusion . CFU-K562 were cultured in 0.8 % methylcellulose . P210 was measured by flow cytomety RESULTS: K562 cells were treated with Aspo, they still grew in clone state and show antisense sequence specific and dose dependent. When the concentration of Aspo was more than Spznol/L, the growth of cells was inhibited and P210 was down regulated or completely suppressed, and the greatest growth inhibition was at 120h . There was signifi-cant inhibition of cell proliferation in a rang‘cells number from 1×10⁴/mL to 5×10⁴/mL after treatment with 10unol/L Aspo. b2a2 Aspo was also effect on K562 cells which expressing b3a2 mRNA.CONCLUSION: bcr-abl Aspo has a specific growth inhibition effect on K562 cells, and worths further study in CML gene therapy.     

Apoptosis induced by berbamine in K562 cells correlates with the expression levels of bcr/abl gene and P210

AIM: To explore the effect of berbamine(BER) on apoptosis in K562 cells and its possible molecular mechanisms. METHODS: The apoptosis rate was measured by flow cytometry while electron microscopy and DNA electrophoresis were used to evaluate the characteristic changes of apoptosis, RT-PCR and Western blot were used to examine the expression levels of apoptosis related gene bcr/abl and BCR/ABL protein. RESULTS: By FCM, the apoptosis rate of K562 cells treated with 8.0 mg/L BER for 24 h and 72 h increased from (29.20±3.82)% to (61.77±4.35)% (P＜0.01); The typical apoptosis morphologic changes and the DNA ladder were more clearly observed. After treated with BER 0 to 16.0 mg/L for 24 h, the expression levels of bcr/abl mRNA and P210 (semiquantity value) decreased quickly from 1.19±0.02 to 0.73±0.02 (P＜0.01) and from 1.04±0.02 to 0.63±0.01 (P＜0.01), respectively. CONCLUSION: BER induces apoptosis of K562 cells in a time-and-concentration-dependent manner, the decline of bcr/abl mRNA and P210 may play an important role in the apoptotic effect of BER in K562 cells. BER could be used as a new clinical trials for bcr-abl⁺ diseases such as CML.