Down-regulation of JARID1B expression inhibits cell proliferation, induces apoptosis and blocks cell cycle in human acute lymphoblastic leukemia cells.

OBJECTIVE

Acute lymphocytic leukemia (ALL) is a multi-factorial blood disease with unknown pathogenesis. Histone H3K4 methylation was significantly reduced in ALL patients, whereas jumonji AT-rich interactive domain 1B (JARID1B) was the specific demethylase of H3K4me. This study explores the expression level of JARID1B in ALL patients and down-regulated JARID1B expression in ALL cells to explore the function of JARID1B in ALL.

PATIENTS AND METHODS

JARID1B mRNA expression level in ALL patients was detected by Real-time PCR. The peripheral blood mononuclear cells from healthy volunteers were selected as control. JARID1B shRNA was transfected with MOLT-4 cells and BALL-1 cells. JARID1B protein expression and H3K4me2 and H3K4me3 levels were detected by Western blot assay. Cell proliferation was assessed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. Cell apoptosis and cell cycle were determined by flow cytometry. Bcl-2, Bax, Procaspase 3, and cyclin P21 expressions were evaluated by Western blot assay.

RESULTS

JARID1B mRNA expression in primary bone marrow cells from ALL patients was significantly higher than that of healthy volunteers (p<0.05). The levels of histone H3K4me3 and H3K4me2 were up-regulated after JARID1B shRNA transfection. JARID1B shRNA significantly inhibited the proliferation of MOLT-4 and BALL-1 cells, induced apoptosis, and blocked cell cycle in G0/G1 phase compared with the control group (p<0.05).

CONCLUSIONS

JARID1B is highly expressed in ALL. Down-regulating its expression inhibited leukemia cell proliferation, promoted apoptosis, and blocked cell cycle in G0/G1 phase through histone H3K4 methylation. JARID1B is an oncogene in ALL.