AIM: To investigate the effects of gemcitabine (GEM) , a novel analog of deoxycytidine and nucle-oside reductase inhibitor similar to cytarabine ( Ara-C) in structure, on the proliferation and apoptosis of myeloid leukemic stem cells ( LSCs) , CD34 + CD38- KGla cells. METHODS: The expression of CD34 and CD38 on the surface of acute myeloid leukemia KGla cells was detected by flow cytometry. The effects of GEM at various concentrations for 24 h and sustained medication for 14 d and 21 d on the proliferation and colony-forming ability of KGla cells were analyzed by soft agar colony-forming experiment. The changes of the cell cycle of KGla cells treated with various concentrations of GEM were tested by flow cytometry. The apoptosis of KGla cells was determined by flow cytometry with the staining of Annexin V-FITC and propidium iodide (PI). RESULTS: The percentage of CD34 + CD38- cells in acute myeloid leukemia KGla cells was (98.02 ±0.72) %. Treatments with 0. 05 mg/L and 0.1 mg/L GEM for 24 h were similar to saline control group in cell cycle distribution of the KGla cells, whereas KGla cells treated with 0. 5 mg/L GEM for 24 h were arrested at G0/G1 phase. After treatment with 0.1 mg/L and 0.5 mg/L GEM for 24 h, the colony numbers at 14 d and 21 d were lower than that in saline control group. No difference of the colony numbers between the cells treated with normal saline and 0.05 mg/L GEM for 14 d and 21 d was observed. After sustained medication with 0. 05 mg/L, 0.1 mg/L and 0. 5 mg/L GEM and Ara-C for 14 d and 21 d, the colony numbers decreased as compared to saline control group. Treatment with 0. 5 mg/L GEM for 24 h increased the apoptotic rate of KGla cells compared with saline control group, while treatments with 0.05 mg/L and 0.1 mg/L GEM for 24 h were similar to saline control group in cell apoptosis. CONCLUSION: GEM inhibits the proliferation and colony-forming ability, arrests the cell cycle at G0/G1 phase and induces apoptosis of CD34+ CD38- acute myeloid leukemia cells.%目的:探讨与阿糖胞苷(Ara-C)结构相似的新型脱氧胞苷相似物和核苷还原酶抑制剂——吉西他滨(gemeitabine,GEM)对CD34+ CD38-KGla髓系白血病干细胞(LSCs)增殖抑制和诱导凋亡的影响.方法:流式细胞术检测急性髓系白血病KGla细胞表面CD34和CD38的表达；24 h和持续用药软琼脂克隆形成实验观察不同浓度GEM对KG1a细胞增殖的影响,流式细胞术检测不同浓度GEM对KGla细胞周期的影响,Annexin V/PI双染法检测不同浓度GEM对KGla细胞凋亡的影响.结果:急性髓系白血病KGla细胞中CD34+CD38-占(98.02±0.72)％.0.05 mg/L、0.lmg/L和0.5 mg/L的GEM分别作用KGla细胞24h、48 h和72 h后,0.5 mg/L GEM作用KGla细胞24h后, G0/G1期细胞高于盐水对照组(P＜0.05),而0.05 mg/L和0.1 mg/L GEM作用KGla细胞24h后,G0/G1期细胞与盐水对照组相比,差异无统计学意义(P＞0.05).0.05 mg/L、0.1 mg/L和0.5 mg/LGEM作用KGla细胞24h后,软琼脂培养第14 d和21d后,0.1mg/L和0.5 mg/L组形成的克隆数,低于盐水对照组(P＜0.05),0.05 mg/L GEM组14 d、21 d的克隆数与对照组相比,差异无统计学意义(P＞0.05).0.05 mg/L、0.1 mg/L、0.5 mg/L GEM和Ara-C持续作用组,软琼脂培养14 d和21d均未见集落生长,与对照组相比差异显著(P＜0.05).0.05 mg/L、0.1 mg/L GEM作用KG1a细胞后其凋亡率与盐水对照组相比,差异无统计学意义(P＞0.05),而0.5 mg/L GEM作用24h后KGla细胞凋亡率显著高于盐水对照组(P＜0.05).结论:GEM能抑制CD34+CD38-髓系白血病干细胞增殖和克隆形成,并将CD34+ CD38-KG1a细胞阻滞在G0/G1期和诱导其凋亡.
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