高三尖杉酯碱诱导白血病细胞凋亡与人端粒酶逆转录酶及端粒酶的关系

The relationships between apoptosis of leukemic cells induced by homoharringtonine and telomerase activity and human telomerase reverse transcriptase

目的 研究高三尖杉酯碱 (HHT)诱导白血病细胞凋亡与细胞端粒酶和端粒酶逆转录酶 (hTERT)水平的关系。方法 在体外 ,以HL60细胞株细胞为对象 ,采用半定量RT PCR法检测hTERTmRNA表达量 ;采用端粒重复序列扩增法 (TRAP) 酶联免疫吸附试验 (ELISA)检测端粒酶活性 ;采用TUNEL法检测凋亡细胞。结果 与空白对照相比 ,HHT能够下调hTERTmRNA的表达。HHT浓度为 0 .0 0 5～ 0 .0 3 0 μg/ml时 ,HL60细胞hTERTmRNA表达无明显变化 ;当浓度增至 0 .0 40～ 0 .0 5 0 μg/ml,hTERTmRNA表达量下降至检测不出。0 .0 2 0 μg/mlHHT作用 18h后 ,hTERTmRNA表达呈下降趋势 ,2 4h后端粒酶活性明显下降 ,两者的下降趋势基本相似 ,但hTERTmRNA表达下降幅度较端粒酶活性下降幅度更大。在HHT作用下 ,HL60细胞凋亡率增加 ,而端粒酶活性及hTERTmRNA水平下降 ,且与HHT浓度或作用时间相关。结论 HHT下调端粒酶活性可能与hTERTmRNA转录水平下降有关。

Objective To explore the role of the telomerase and human telomerase reverse transcriptase(hTERT) in apoptosis induced by homoharringtonine(HHT). Methods The expression of hTERT mRNA was analyzed by semi quantitative RT PCR and telomerase activity, under the examination of TRAP ELISA in HL60 line cells. The rate of apoptosis was examined by TUNEL method. Results Compared with the control, the HL60 cells treated with HHT at 0.005 ～ 0.03 μg/ml for 12 hours showed no significant synthetic level change of hTERT mRNA, but reduced obviously at 0.04 μg/ml HHT and was undetectable at 0.05 μg/ml . When HL60 cells were cultured with 0.02 μg/ml HHT, the level of hTERT mRNA began to decrease after 18h, and telomerase activity decreased after 24 h. Increasing HHT concentrations and duration, the apoptosis of HL60 cells increased, whereas the telomerase activity and hTERT mRNA expression decreased. Conclusion Down regulating the transcription of hTERT and telomerase activity might be one of the mechanisms in HHT induced apoptosis of HL60 line cells.