[Difluoromethylornithine synergizes with antisense bcl-2 RNA in the induction of apoptosis of HL60 cells].

OBJECTIVE: To study the combined effect of difluoromethylornithine (DFMO) and bcl-2 antisense RNA in the induction of apoptosis of HL60 cells. METHODS: HL60 cells were transfected with recombinant retroviral vector expressing bcl-2 antisense RNA. The growth characteristics of transfectants were studied by morphological observation, growth curve, FCM analysis, colony formation in soft agar, DNA electrophoresis, molecular hybridization and immunocytochemical staining. RESULTS: The recombinant retroviral vectors expressing bcl-2 antisense RNA and the cell line producing recombinant virus were constructed. Although the expression of bcl-2 at mRNA and protein levels in the HL60 cells transfected with antisense bcl-2 were down-regulated, there was no change in cell growth, cell cycles and expression of ornithine decarboxylase (ODC) compared with the parental cells albeit some decrease in colony formation. In addition, transfection with antisense bcl-2 did not induce marked apoptosis whereas treatment of the transfectant with low concentration (0.2 mmol/L) of DFMO resulted in enhanced expression inhibition of bcl-2 protein, inhibition of cell growth and induction of apoptosis. CONCLUSION: DFMO synergizes with antiense bcl-2 RNA in the induction of apoptosis of HL60 cells.