This study was aimed to investigate the effect of
small interfering RNA (
siRNA) on the expression of mll-af9 oncogene and the proliferation of human
acute monocytic leukemia cell line THP-1. One group of
siRNA was designed targeting mll-af9
mRNA and finally obtained by chemosynthesis. Then the obtained
siRNA was transfected into cultured human
acute monocytic leukemia cell line THP-1 by
lipofectamine. Flow cytometry was used to detect
siRNA transfection efficiency. The level of mll-af9
mRNA expression was analyzed by reverse transcription polymerase chain reaction (RT-PCR). The cell proliferation rate was assayed by MTT. The change of cell cycles and apoptosis rate was detected by flow cytometry. The results showed that the
siRNA transfection efficiency was 69.1%+/-1.8%. The level of mll-af9
mRNA expression was significantly inhibited in
siRNA-transfected cells as compared with the controls. mll-af9-targeted
siRNA inhibited the proliferation of THP-1 cells and induced cell apoptosis effectively after transfection. The percentage of G0/G1 phase cells significantly increased in
siRNA-transfected cells in comparion with the control cells, but the percentage of S phase cells significantly decreased. It is concluded that the mll-af9-targeted
siRNA can effectively inhibit the proliferation of human
acute monocytic leukemia cell line THP-1.