Anti-tumor effect of 5-aza-2'-deoxycytidine by inhibiting telomerase activity in hepatocellular carcinoma cells

AIM:To investigate the effect of the demethylating reagent 5-aza-2'-deoxycitidine(DAC) on telomerase activity in hepatocellular carcinoma(HCC) cell lines,SMMC-7721 and HepG2.METHODS:The related gene expression in cell lines was examined by real-time reverse transcription-polymerase chain reaction and Western blotting analysis.The telomerase activity was examined by telomeric repeat amplification protocol-enzyme-linked immunosorbent assay and DNA methylation was determined by methylation-specific polymerase chain reaction.RESULTS:The telomerase activity was significantly reduced in both cell lines treated with DAC,accompanied by downregulation of telomerase reverse transcriptase(hTERT).We also observed the effect of DAC on the methylation status of hTERT promoter and the expression of regulatory genes,such as c-myc,p15,p16,p21,E2F1,and WT1.The methylation status of hTERT promoter could be reversed in SMMC-7721 by DAC,but not in HepG2 cells.However,p16 expression could be reactivated by demethylation of its promoter,and c-Myc expression was repressed in both cell lines.Moreover,DAC could enhance the sensitivity to the chemotherapeutic agents,such as cisplatin,by induction of apoptosis of HCC cells.CONCLUSION:The DAC exerts its anti-tumor effects in HCC cells by inhibiting the telomerase activity.

Mucin 1 and interleukin-11 protein expression and inflammatory reactions in the intestinal mucosa of necrotizing enterocolitis children after surgery

BACKGROUND Necrotizing enterocolitis(NEC)of the newborn is a frequently occurring clinical disease in infants.The mortality rate of NEC in premature infants is as high as 50%,and the morbidity rate is on the rise.NEC has already caused serious impacts on newborn survival and poses serious threats to both children and families.AIM To investigate the expression and significance of mucin 1(MUC1)and interleukin-11(IL-11)in the intestinal mucosa of infants with neonatal NEC after surgery.METHODS Forty-eight postoperative intestinal mucosal specimens from children with NEC(NEC group)and twenty-two intestinal mucosal specimens from children with congenital intestinal atresia(control group)were collected in our hospital.Immunohistochemical staining and Western blot analysis were used to examine the protein expression of MUC-1 and IL-11 in the two groups.The serum levels of tumor necrosis factor-α(TNF-α)and IL-1βin the two groups were measured by enzyme-linked immunosorbent assay,and the relationship between MUC-1 and IL-11 protein expression and serum TNF-αand IL-1βlevels was analyzed by the linear correlation method.RESULTS The protein expression of MUC-1 and IL-11 in the NEC group was significantly lower than that in the control group,and the difference was statistically significant(P<0.05).The levels of serum TNF-αand IL-1βin the NEC group were significantly higher than those in the control group(P<0.05).The protein expression of MUC-1 and IL-11 in the NEC group negatively correlated with serum TNF-αand IL-1βlevels(P<0.05).There was a significant negative correlation between the protein expression of MUC-1 and IL-11 and the levels of serum TNF-αand IL-1βin the NEC group.CONCLUSION The protein expression of MUC1 and IL-11 in the intestinal mucosa of children with NEC is significantly downregulated after surgery.This downregulation may be involved in the pathogenesis of this disease and has a certain correlation with inflammatory response factors in children with NEC.