Study In The Effect Of DNMT1Gene Targeting SiRNA On Histone Modulation In Molt-4Cell Line

Objective: To study the effect of small interfering RNA (siRNA) targetingDNMT1gene on cell proliferation, apoptosis and histone methylation and acetylationin Molt-4cells line, we study its potential mechanism.Methods：(1) Four siRNA segments targeting DNMT1gene were designed andtransfected into Molt-4cells by LipofectamineTM2000. The optimal segment wasscreened by RT-PCR.(2) Cell growth affected by DNMT1siRNA was determined byMTT. Cell apoptosis was measured by Flow cytometry.(3) The expression of Bcl-2,procaspase-3, P15, histone methylation of H3K9, H3K4and histone acetylation of H3was detected by Western blot.Results:(1) The sequence of optimal segment of siRNA was sense5’-GCACCUCAUUUGCCGAAUATT-3’, antisense5’-UAUUCGGCAAAUGAGGUGCTT-3’.(2) DNMT1siRNA suppressed the proliferation in Molt-4cells.(3)DNMT1siRNA induced cell apoptosis.The expression of Bcl-2, procaspase-3wassuppressed.(4) DNMT1siRNA upregulated P15. DNMT1siRNA downregulatedhistone methylated H3K9and upregulated histone methylated H3K4. Alteration ofhistone acetylation of H3was not seen.Conclusions:(1) LipofectamineTM2000transfected siRNA for DNMT1gene intoMolt-4cells has high efficiency.(2) DNMT1siRNA inhibites cell growth andinduces cell apoptosis in Molt-4cell line. DNMT1siRNA downregulates DNMT1,P15was de novo.(3) DNMT1siRNA decrease histone methylated H3K9andincrease histone methylated H3K4, which involved in gene transcriptional activation.It doesn’t affect histone acetylation of H3. It might be a new therapeutic target in anti-human leukemia. The mechanism need to be further studied.