FLT3靶向短发夹状干扰RNA体外转录合成及作用

In Vitro Transcription Synthesis and Effects of FLT3 Targeted Short Hairpin RNA

FMS样酪氨酸激酶3(FLT3)是一种酪氨酸激酶受体,在大多数急性髓系白血病(AML)患者中持续激活,与患者预后差密切相关。为探讨3种FLT3靶向短发夹状干扰RNA(shRNA)对急性髓系白血病细胞株THP-1的沉默效应,设计和体外转录合成3个FLT3靶向shRNA(shRNA1、shRNA2、shRNA3),体外转染THP-1细胞;以RT-PCR法检测FLT3mRNA水平表达,用流式细胞术、免疫荧光测定法检测FLT3蛋白的表达。结果显示:shRNA1、shRNA3可显著下调FLT3mRNA的表达,其中shRNA1的抑制作用较强。25nmol/LshRNA1转染48小时对FLT3mRNA的抑制率是(72.95±2.07)%,作用可达72小时。5nmol/L及以上浓度的shRNA1对FLT3mRNA表达有下调作用,作用存在量-效关系。15nmol/LshRNA1的抑制率是(67.53±0.66)%。FLT3蛋白位于细胞膜上,shRNA1对其有较强的抑制作用,转染72小时蛋白抑制率达(79.67±0.66)%。结论:FLT3-shRNA1具有较好的FLT3基因靶向抑制作用,可作为进一步研究该基因作用机制及靶向治疗可能性的工具。

FMS-like tyrosine kinase 3 （ FLT3 ） is a receptor of tyrosine kinase that is constitutively activated in most of acute myeloid leukemia patients and seems to give an adverse prognosis. In order to explore the silencing effect of FLT3 targeted short hairpin RNA （FLT3-shRNA） on acute leukaemia cell line THP-1, three FLT3-shRNAs （ shRNA1, shRNA2, shRNA3 ） were designed and synthesized by transcription system in vitro and then transfected into THP-1 cells. FLT3 mRNA was analyzed by semi-quantitative RT-PCR, FLT3 protein was detected by Flow cytometry and immunofluorescence. The results indicated that FLT3 expression was downregulated by shRNA1 and shRNA3, and shRNA1 showed stronger inhibitory effect. At 48 hours following transfection, the inhibitory rate of 25 nmol/L shRNA1 was 72.95 ± 2.07%, lasting 72 hours. The 5 nmol/L and more concentration of FLT3 shRNA1 could downregulate FLT3 mRNA level, which displayed a quantity-effect relation; the inhibitory rate of 15 nmol/L shRNA1 was 67.53 ± 0.66%. FLT3 protein was located on THP-1 cell membrance, its expression was downregulated obviously by shRNA1, at 72 hours following transfection the inhibitory rate of shRNA1 was 79. 67 ± 0.66%. shRNA1 showed the best inhibitory effect on FLT3 protein, the optimal time of which was 72 hours with an inhibitory rate of 79.67%. It is concluded that FLT3-shRNA1 shows a desireable FLT3-targeted inhibitory effect, which can be used for further investigation of FLT3 mechanism or FLT3 targeting treatment.