Effect of Silencing DNMT1 gene on histone methylation modulation, cell proliferation and apoptosis in Molt-4 cell line / 中国药理学通报

ABSTRACT

Aim To investigate the effect of small in-terfering RNA(siRNA) targeting DNMT1 gene on cell proliferation, apoptosis and histone modulation in acute lymphoid leukemia cell line, Molt-4. Methods The small interfering RNA targeting DNMT1 gene was transfected into Molt-4 cells by LipofectamineTM 2000. The DNMT1 mRNA and protein level were detected by RT-PCR and Western blot. Cell proliferation was de-termined by MTT. Cell apoptosis was measured by Flow Cytometry. The expression of Bcl-2, procaspase-3, P15, histone methylation and histone acetylation was detected by Western blot. Results DNMT1 was suppressed by siRNA targeting DNMT1 in a concentra-tion-dependent manner. DNMT1 siRNA suppressed cells proliferation and induced apoptosis in Molt-4 cells. Apoptotic rate was (4. 27 ± 1. 42)% , (15. 25 ± 1. 54)% , (35. 63 ± 2. 54)% , (66. 27 ± 3. 02)%after transfecting with DNMT1 siRNA at 0, 30, 60, 120 nmol·L - 1 for 24 hours, P < 0. 05. The expres-sion of Bcl-2, procaspase-3 was suppressed and P15 was promoted after transfecting of DNMT1 siRNA. DN-MT1 siRNA downregulated histone methylated H3K9 and upregulated histone methylated H3K4. The altera-tion of histone acetylation of H3 was not seen. Conclu-sion DNMT1 siRNA suppresses DNMT1 efficiently in Molt-4 cells. The depletion of DNMT1 downregulates histone methylation of H3K9, and upregulates histone methylation of H3K4. It inhibits cell growth and in-duces cell apoptosis in Molt-4 cell line.