血管内皮生长因子反义寡核苷酸增强髓系白血病细胞对三尖杉酯碱敏感性

目的探讨血管内皮生长因子(VEGF)反义寡核苷酸对急性髓系白血病(AML)、慢性粒细胞白血病(CML)细胞的三尖杉酯碱敏感性的影响及其可能的机制。方法采用以前实验筛选所获得的VEGF最优反义寡核苷酸A7，长度为20个脱氧核糖核苷酸，全硫代修饰；在低血清(2％)条件下，以脂质体介导转染细胞8h，调整培养液血清浓度至10％。24h后加入三尖杉酯碱继续培养至72h，用锥虫蓝拒染法计数活细胞，用ELISA法检测培养液中VEGF蛋白的浓度，用流式细胞仪检测细胞凋亡百分率。结果与随机对照序列联合三尖杉酯碱组相比，VEGF反义寡核苷酸与三尖杉酯碱联用可显著抑制AML、CML细胞存活(AML组存活细胞数下降38％，CML组存活细胞数下降25％)，并下调VEGF蛋白的表达(AML组蛋白表达下降25．44％，CML组蛋白表达下降30．81％)，增加三尖杉酯碱诱导的AML、CML细胞凋亡百分率(AML组凋亡细胞百分率增加48．29％，CML组凋亡细胞百分率增加52．76％)。结论VEGF反义寡核苷酸可提高AML、CML细胞对三尖杉酯碱的敏感性；白血病细胞分泌的内源性VEGF蛋白具有抵抗药物杀伤作用。

Vascular endothelial growth factor antisense oligodeoxynucleotide enhance drug-sensitivity of myeloid leukemia cells to homoharringtonin

Objective To explore the effects of antisense phosphrothioate oligodeoxynucleotides (AS PS-ODN) of vascular endothelial growth factor (VEGF) on drug-sensitivity of AML and CML cells to homoharringtonin and its possible mechanism. Methods A7, which was the most effective AS PS-ODN selected by computer aid-designing and experimental assay, contains 20-mer modified with phosphrothioate. It was transferred into cells by lipofectin while cultured in 2% serum medium for 8 h and then in 10% serum medium. Twenty four hours later, homoharringtonin was added into the culture and cultured for another 48 h. Cell viability was detected by trypan blue exclusion every 24 hours, cell apoptosis by flowcytometry, and level of VEGF protein by a VEGF ELISA kit. Results The combination of A7 and homoharringtonin was able to inhibit cell survival (AML cell survival reduced 38%, CML cell survival reduced 25%), downregulate VEGF protein expression (VEGF protein expression of AML cell and CML cell declined 25.44% and 30.81%,respectively) and increase homoharringtonin induced apoptosis in both AML and CML cells (apoptotic rates of AML and CML cells increased 48.29% and 52.76%, respectively). Conclusion The VEGF AS PS-ODN is able to enhance the drug-sensitivity to homoharringtonin, suggesting that inner VEGF proteins in myeloid leukemia cells had a drug-resistant effect.