OBJECTIVETo study the effects of suppressor of variegation 3-9 homolog 1 (SUV39H1) gene silencing by small interfering RNA (siRNA) on the proliferation, tumor suppressor gene p15 expression and histone modification in acute myeloid leukemia cell line KG-1 cells, and to explore novel therapeutic target of leukemia.

METHODSThe SUV39H1 gene specific siRNA was synthesized in vitro and transfected into KG-1 cells by Lipofectamine(TM) 2000. The SUV39H1 mRNA and protein were detected by RT-PCR and Western blot. Cell growth affected by SUV39H1 siRNA was determined by MTS. The expressions of tumor suppressor gene p15, histone methylation of H3K9 and histone acetylation of H3, H3K9, H3K14, H3K27 and H4 were detected by Western blot.

RESULTSSUV39H1 mRNA was markedly suppressed by the SUV39H1 specific siRNA in a concentration-dependent manner. SUV39H1 siRNA inhibited the proliferation of KG-1 cells. Proliferation inhibition rate was (23.57 ± 1.98)%, (48.69 ± 1.84)%, (62.69 ± 1.61)% and (81.06 ± 3.22)% after transfected with SUV39H1 siRNA at 30, 60, 120 and 240 nmol/L for 48 hours, respectively. SUV39H1 siRNA down-regulated histone tri-methylated-H3K9 by 25%, 33% and 49% compared to control group when treated with SUV39H1 siRNA at 30, 60 and 120 nmol/L for 48 hours, while up-regulated histone acetylated H3K9 by 1.83, 2.16 and 3.07 folds, and global histone H3 in 1.35, 1.87 and 2.37 folds, but no changes were observed in histone acetylation of H3K14, H3K27 and H4. Expression of p15 increased 1.52, 2.89 and 3.08 folds after SUV39H1 siRNA treatment.

CONCLUSIONSSUV39H1 gene silencing could induce the re-expression of p15 and inhibit cell proliferation by down-regulation of histone methylation of H3K9, up-regulation of histone acetylation of H3K9 and global H3. SUV39H1 might be a new target for cancer therapy.