siRNA Targeting bcl-2 Gene Improve H and RA Drug-Sensitivity in HL-60 Cells.

The anti-apoptosis gene, bcl-2, is also related to drug-resistance, which expresses markedly higher on all kinds of leukemia. small interference RNA can silence the targeted mRNA expression.

Objective: To study the effect of G3139 and siRNA targeting bcl-2 gene which increase the sensitivity of HL-60 cell to HT, Ara-C, As₂O₃ and RA.

Method:Incubate leukima cell HL-60 with H, Ara-C, As₂O₃ and RA, meanwhile transfected siRNAs or G3139 in it by lipofectamine2000 with OPTI-MEM cultural medium for 6h, then add equal volume RPMI-1640 culture medium containing 20% inactive newborn calf serum. After transfection for 24,48 and 72h, cell proliferations were determined by MTT method. After transfection for 48h, we test the level of Bcl-2 protein, ROS and membrane potential of mitochondrion in HL-60 cell by FCM.

Result:

1. Compare with control group, the G3139 and siRNA targeting bcl-2 combine with H or Ara-C or As₂O₃ have significant effects on inhibiting the proliferation of HL-60(P <0.05); After transfecting 48h, the level of Bcl-2 protein and ROS decrease significantly, meanwhile membrane potential of mitochondrion in HL-60 cells increase markedly (P<0.01).

2. Compare with control group, the G3139 and siRNA targeting bcl-2 combine with RA have significant effects on inhibiting the proliferation of HL-60 and the level of Bcl-2 protein decrease, but there were not difference between test groups and control group on the level of ROS and membrane potential of mitochondrion (P<0.01).

Conclusion: The effective siRNA2, targeting bcl-2, can increased the drug-sensitivity though inhibiting the expression of Bcl-2 protein. Different drug has different mechanism to induce the leukimic cell apoptosis.