OBJECTIVETo study the effects of bcl-2 antisense phosphorothioate oligonucleotides (ASPO) on suppression of HL-60 cell growth in SCID mice and to investigate the feasibility of purging leukemia cells plus bcl-2 ASPO used in vitro.

METHODS1 x 10(7) viable HL-60 cells were treated with 10 micro mol/L bcl-2 ASPO seven days before the intraperitoneal (IP) inoculation to the SCID mice, Treatment with sense oligonucleotides (SPO) was similar as for the controls. 35 days after the inoculation, all the SCID mice of both groups were sacrificed and their peripheral blood, bone marrow, liver and spleen were examined using half nested RT-PCR and histopathology for detecting the appearance and distribution of the HL-60 cells treated beforehand with antisense or sense oligonucleotides respectively.

RESULTSASPO could down regulate the expression of bcl-2 resulting in both inhibition of growth and induction of apoptosis in treated HL-60 cells, which failed to develop leukemia in SCID mice at all. However, SPO treated HL-60 cells still behaved their own ways and proliferated agressively, and developed leukemia at last.

CONCLUSIONThe bcl-2 ASPO enables to suppress HL-60 cell growth and prevent the development of leukemia in the SCID mice. The purging leukemia cells used are seemed liable in inhibiting the development of leukemia in SCID mouse model.