ABSTRACT
Objective To investigate the effect of 5-AZA-2'-dC on Angiotensin Ⅱ (Ang Ⅱ)-induced cardiomyocyte hypertrophy.Methods Cultured cells derived from neonatal heart of rat were divided into 5 groups:normal control,hypertrophic group,5-AZA-2'-dC treatment group,and 5-AZA-2'-dC pretreatment group.Neonatal rat cardiomyocyte hypertrophic response was assayed by the size of cardiomyocytes and atrial natriuretic polypeptide (ANP) expressive level.The level of sarcoplasmic reticulum Ca2+ ATPase (SERCA2a),total calmodulin kinase Ⅱ (CaMK Ⅱ) and phospho-CaMK Ⅱ (p-CaMK Ⅱ) detected by Western blot.The intracellular calcium changes of cardiomyocytes were imaged by confocal fluorescent microscopy.Results Cells treated with Ang Ⅱ at 10-6 mol/L for 48 h were chosen as hypertrophic cardiomyocyte model.The mRNA expression and protein level of ANP were significantly decreased in the treatment and pretreatment groups compared with hypertrophic group.The protein level of SERCA2a was significantly decreased in the hypertrophic group,and increased in the treatment and pretreatment group compared with hypertrophic group.The protein level of SERCA2a was significantly decreased in the hypertrophic group,and increased in the treatment and pretreatment group compared with hypertrophic group,whereas phospho-CaMK Ⅱ showed an opposite change tendency.The time required for increasing and declining to half of the intracellular calcium peak value were both delayed in hypertrophic group,as the treatment and pretreatment groups showed shorter time required compared with hypertrophic group.Conclusion 5-AZA-2'-dC could inhibit Ang Ⅱ-induced cardiomyocyte hypertrophy which might be related to regulate SERCA2a expression.Increased SERCA2a expression may maintain the calcium homeostasis through shortening the time of transfer Ca2+ from the cytosol of the cell to the lumen of the sarcoplasmic reticulum.
ABSTRACT
Objective To explore the effect of DNA methylation inhibitor 5-aza-2'-deoxycytidine (5-Aza-CdR) on proliferation and tumor suppressor gene PRDM1α expression in Burkitt's lymphoma cell line NAMALWA. Methods MTT was used to study the impact of DNA methylation inhibitor on proliferation in NAMALWA cells,and comparative real-time reverse transcription-polymerase chain reaction (RQ-PCR) with SYBR Green assay was used to detect PRDM1α gene expression. Results MTT results showed that 5-AzaCdR inhibited proliferation of NAMALWA cells in a dose-dependent manner.After treated with 5-Aza-CdR for 72 h at 0.01,0.0625,0.1,0.125,0.25,0.5,1,2 and 4 μmol/L,the inhibition rates were 21.93 ％,39.23 ％,47.69 ％,50.37 ％,53.54 ％,57.72 ％,62.31％,65.68 ％,67.87 ％,respectively,and the differences of absorbance among the groups were also statistically significant (all P＜ 0.01). Meanwhile, 5-Aza-CdR could induce the re-expression of PRDM1α, and △Ct of 0.5, 1, 2 μmol/L groups showed significant differences compared with control group (all P ＜ 0.05). Conclusion DNA methylation inhibitor 5-Aza-CdR can significantly inhibit the proliferation of Burkitt' s lymphoma cell line NAM ALWA,and the possible mechanism of this inhibition may be induction of demethylation and re-expression of PRDM 1α.