Abstract: Objective To investigate the effect of silencing histone deacetylases1 (HDAC1) gene by RNA interference on the
proliferation, apoptosis and histone modulation in gastric cancer MGC-803 cell line. Methods The optimal segment targeting
HDAC1 gene was designed and transfected into MGC-803 cells by Lipofectamine TM2000. HDAC1 mRNA and protein in the
transfected cells were detected by RT-PCR and Western blotting, respectively. The growth inhibition of MGC803 cells was
evaluated by MTT assay and the cell apoptosis was detected with TUNEL assay. The expression of Bcl-2, procaspase-9,
procaspase-3, c-Myc, histone acetylation of H3, H4, and histone methylation of H3K9 was detected by Western blotting.
Results The siRNA targeting HDAC1HDAC1 markedly suppressed mRNA expression, inhibited cell proliferation and induced
apoptosis of MGC-803 cells in a concentration manner. Transfection of the cells with HDAC1 siRNA at 0, 30, 60, and 120 nmol/L
for 24 h resulted in a cell apoptotic rate of (4.8 ±2.7)%, (18.5 ±3.5)%, (41.4 ±4.3)%, and (59.2 ±5.5)%, respectively, and caused
down-regulation of the expressions of Bcl-2, proCaspase9, proCaspase3 and c-Myc, upregulation of histone acetylation of H3,
H4, and down-regulation of histone methylation of H3K9. Conclusion Silencing HDAC1 gene expression with HDAC1 siRNA
can promote histone H3 and H4 acetylation and inhibit histone methylation of H3K9 to suppress the proliferation and induce
apoptosis of gastric cancer MGC-803 cells.