Abstract: Objective To investigate the antitumor activities and apoptosis mechanisms of 4β-N-〔4"-(2",2",6",6"-tetramethyl-1",2",5",6"-tetrahydrogenpyridine-1"-nitroxyl)-amido〕-4'-demethylepipodophyllotoxin(GP-14) on HL-60 cells.Methods MTT colorimetric assay,electron microscope,agar gel electrophoresis and flow cytometry were used to detect the effects of GP-14 on HL-60 cells.The telomerase activity was detected by TRAP-ELISA assay.Results The growth of HL-60 cells were suppressed apparently by GP-14.In some extent of dosage and time,GP-14 induced the apoptosis of HL-60 cells.The apoptosis rate was 43.8% incubated by 5.0μmol/LGP-14 for 48 hours.GP-14 resulted in the inhibition of telomeraseactivity.Conclusion GP-14 could induce the apoptosis of HL-60,inhibit telomeraseactivity specifically.It's inhibitation was stronger than that of VP-16 with same concentration,which provided basis for further study for clinical use.