Background and purpose: Apollon gene is highly expressed in leukemia and other tumors. The study aimed to discuss whether RNAi technology can reverse multidrug resistance of chronic myeloid leukemia cell line K562 through constructing a eukaryotic vector of short hairpin RNA (shRNA) targeting at Apollon gene. Methods: The eukaryotic vector pGPHI-GFP-Neo-Apollon with shRNA targeting at Apollon gene was constructed a

nd then transfected into K562 cells by Lipofectamine

TM

2000

and G418 pressure selection. Reverse transcription-polymerase chain reaction (RT-PCR) and immunofluorescence were used to detect the expression of Apollon mRNA and protein after Apollon was transfected stably in K562 cells. The changes of sensitivity of K562 cells to leurocristine (VCR) and etoposide (VP16) after transfection with shRNA-Apollon were detected by MTT method

and the apoptosis rate was detected by flow cytometry. Results: pGPHI-GFP-Neo-Apollon carrier was constructed successfully and expressed stably in K562 cells

and after G418 screening

it silenced Apollon mRNA and protein expression effectively. According to the result of MTT

the sensitivity of K562 cells to VCR and VP16 increased significantly in the group of gene interference

with half of its inhibition concentration (half-inhibitory

IC

50

) value significantly lower than the control group (P0.05); Flow cytometry showed that the cell apoptosis rate was increased significantly (P0.05)

but there was no statistically significant difference in the apoptosis rate between shRNA negative control group and normal control group (P0.05). Conclusion: pGPHI-GFP-Neo-Apollon carrier can enhance the abilities of VCR and VP16 to induce the apoptosis of K562 cells

namely an increase of sensitivity to these chemotherapeutics in K562 cells

it is hinted that RNA interference targeting Apollon gene may reverse the multidrug resistance of leukemia cells in some degree.