ABSTRACT
Background and purpose:Ara-C is one of the most effective and common agents in the treatment of acute nonlyphocytic leukemia. Telomerase is a unique complex of ribonucleoprotein. It plays an important role in the pathogenesis and development of cancer. In this study, we investigate the changes of mRNA expression of telomerase subunits in HL-60 cells induced by Ara-c and try to come up with a theory that could help to assess the efficacy of Ara-C. Methods:The combinations of various Ara-C concentration and the incubation time were used to treat HL-60. The ratios of apoptotic cell to necrosis cell were determined by flow cytometry and the expressions of telomerase subunits mRNA were evaluated by RT-PCR.Results:① There was no influence on transcription of telomerase subunits gene after HL-60 cells was cultured with 0~0.2ug/ml Ara-C for 12 hours;② 2ug/ml and 10ug/ml of Ara-C could down regulate the expression of hTERT from 0.80+0.07 to 0.50+0.04 and 0.39+0.03, not hTR and hTP1;③ with longer incubation with 10ug/ml of Ara-C, the percentage of apoptosis could be increased. The maximal induction of apoptosis (18.16+4.25%) could be reached at 12hrs treatment of Ara-C, then gradually decreased later on. The rate of necrosis increased with time, the maximal percentage(57.94+12.03%) of necrosis was observed at 48hrs of incubation time with drug. The mRNA level of hTERT gene also decreased along with the cultured time , the lowest value (0.18+0.03) has been documented at 48hrs time point, but not hTR、TP1.Conclusions:① Ara-C could down-regulate the expression of hTERT mRNA in a dose-and time-dependent manner, but not hTR、hTP1;② There might be no relationship between the percentage of apoptosis induced by Ara-C apoptosis and the expression of telomerase hTERT gene mRNA, but a close relationship between necrosis and the expression of hTERT mRNA has been found.
