Cyclin D1,hTERT Expression and Telomerase Activity in HL-60 and HL-60A Cell Lines and Their Significance

To observe the expression of cyclin D1,hTERT,and telomerase activity in MNC,HL-60,HL-60A and to explore their effects on leukemogenesis and drug-resistance,normal human peripheral blood mononuclear cells,HL-60 cells sensitive to adriamycin and HL-60A cells resistant to adriamycin were investigated.The cell cycle was analyzed by flow cytometry,and the apoptosis was analyzed by Annexin V-FITC+ PI staining.Expressions of cyclin D1 and hTERT were determined by real-time PCR and Western blot.Telomerase activity was detected by TRAP-ELISA.The results indicated that the percentage of MNC,HL-60 and HL-60A in S phase was(10.21+2.11)%,(44.93+ 3.00)%,and(51.38+ 1.10)% respectively;the percentage of apoptosis cells was(16.14+ 2.13)%,(7.53+ 0.92)%,(4.15+ 0.96)% respectively;the expression of mRNA and protein for cyclin D1 and hTERT increased;the telomerase activities of HL-60 and HL-60A were higher(p=0.000),whereas the difference between HL-60 and HL-60A was no statistically significant(p=0.232);positive correlation between cyclin D1,hTERT and telomerae activity had been found(p0.01).It is concluded that the cells of S phase increased while the apoptotic cells decreased in HL-60 and HL-60A,especially in HL-60A,which may be due to the up-regulation of cyclin D1,hTERT and telomerase activity.