OBJECTIVETo investigate the effect of human equilibrative nucleoside transporters 1 (hENT1) silencing on proliferation, apoptosis and demethylation of human myelodysplastic syndrome (MDS) derived cell line SKM-1 treated with 5-aza-2'-deoxycytidine (decitabine, DAC).

METHODShENT1 was silenced in SKM-1 cells mediated by lentivirus transfection. The infection efficiency was detected by flow cytometry, and the mRNA expression level of hENT1 was confirmed by qRT-PCR. The proliferation ratio of SKM-1 cells treated with different concentrations (0.5, 1, 5 mmol/L) of DAC for 24, 48 and 72 h was detected by CCK-8 method after hENT1 silencing. The apoptosis of SKM-1 cells was detected by Western blot for cleaved level of caspase-3 and evaluated by flow cytometry after staining with anti-Annexin V-PE and 7-AAD. The p15(INK4B) DNA methylation status was measured by methylation specific PCR using EZ DNA Methylation-Gold™ Kit.

RESULTSThe expression level of hENT1 silenced group (0.253±0.030) was statistically decreased compared with that in control group (1.000±0.091) (P<0.01). Compared with control, the proliferation inhibition rate of hENT1 silenced group was significantly decreased by different concentrations of DAC (0.5, 1, 5 μmol/L) treatment for 24, 48, 72 h (P<0.05), which was (49.41±4.02)% and (33.03±2.47)%, respectively (P=0.007) at 5 μmol/L DAC treatment for 72 h in hENT1 silenced group and the control group. Western blot showed that cleaved caspase3 of hENT1 silenced group was also significantly inhibited. The percentage of Annexin Ⅴ⁺ cells and demethylation status of p15(INK4B) were significantly decreased.

CONCLUSIONApoptosis of hENT1 silenced SKM-1 cells induced by DAC was decreased, and the susceptibility of these cells to demethylation treatment was also decreased.