OBJECTIVETo explore the biological function of BMAL1 in human acute myeloid leukemia by means of the HL-60 cell line in whica circadian gene BMAL1 was konocked-out by the CRISPR/Cas9 technology.

METHODSTwo sgRNAs for BMAL1 were designed and the PX459 knockout vectors containing the sgRNA were constructed. The activity of 2 sgRNAs was detected by T7 endonuclease I. the BMAL1 knocked out HL-60 cells were prepared by transient transfection of the target vectors into the cells. Western blot was used to detect the expression of BMAL1 protein. The apoptosis of the targeted cells was detected by flow cytometry. The proliferation status of the cells was assessed by the CCK-8 assay.

RESULTSThe PX459-sgRNA vectors were successfully constructed and screened to assure the activity of the targeting vector. It was found that the expression of BMAL1 protein was not detected in BMAL1-knocked out HL- 60 cells. Further, it was shown that BMAL1 knockdout could promote the apoptosis of HL-60 cells and inhibit the cell proliferation ability.

CONCLUSIONBMAL1 knocked out HL-60 cells have bean successfully established using the CRISPR/Cas9 gene editing technique, and BMAL1 knockout can promote the HL-60 cell apoptosis and inhibit its proliferation.These result reveal the biological role of the BMAL1 circadian gene in acute myeloid leukemia.