目的：探讨siRNA靶向沉默 CDX2 基因联合长春新碱（vincristine，VCR）对白血病K562细胞增殖、凋亡的影响。方法： 设计靶向沉默 CDX2 基因表达的特异性siRNA序列CDX2-siRNA-921和相应的阴性对照序列CDX2-siRNA-NC，分别转染K562细胞，同时设正常细胞组做对照。分别应用Real-time PCR和Western blotting法检测转染CDX2-siRNA-921对细胞内 CDX2、BCR-ABL mRNA和蛋白表达的影响；siRNA 和VCR单独或联合作用于K562细胞后，应用MTT、流式细胞术分别检测细胞增殖抑制率、凋亡率的变化。 结果： 与正常细胞组相比，CDX2-siRNA-921能够显著降低目的基因 CDX2 和BCR-ABL mRNA与蛋白的表达（均P<0.05），而CDX2-siRNA-NC组 CDX2 和BCR-ABL mRNA与蛋白表达量无明显变化；与VCR组、CDX2-siRNA-NC组和VCR+CDX2-siRNA-NC组相比，VCR+CDX2-siRNA-921组细胞增殖抑制率降低，凋亡率明显增加（均P<005）。 结论： CDX2-siRN-921能显著降低K562细胞内 CDX2 mRNA和蛋白的表达，并能够下调BCR-ABL融合基因表达水平，同时增强VCR对K562细胞增殖抑制、凋亡诱导作用。

Objective:To investigate the effect of siRNA targeted silencing CDX2 gene combined with vincristine (VCR) on the proliferation and apoptosis of leukemia K562 cells. Methods: Specific siRNA sequence targeted silencing CDX2 gene (CDX2-siRNA-921) and its negative control sequence (CDX2-siRNA-NC) were designed and transfected into K562 Cells respectively. At the same time, untransfected K562 cells were used as a control group. The effect of CDX2-siRNA-921 transfection on the expressions of CDX2，BCR-ABL mRNA and CDX2 protein was detected by Real-time PCR and Western blotting respectively. After action of siRNA and VCR alone or in combination, proliferation inhibition rate and apoptosis rate of the K562 cells were respectively detected by MTT and flow cytometry assays. Results: Compared with the control group, CDX2-siRNA-921 significantly decreased the expressions of targeting gene CDX2 and BCR-ABL mRNA, and CDX2 protein (all P<0.05). But the expressions of CDX2 and BCR-ABL mRNA, and CDX2 protein in CDX2-siRNA-NC group had nonsignificant changes. Compared with CDX2-siRNA-NC、VCR and VCR+CDX2-siRNA-NC groups, the proliferation inhibition rate of the K562 cells significantly decreased and apoptosis rate of the cells significantly increased in VCR+CDX2-siRNA-921 group (all P<0.05). Conclusions: CDX2-siRNA-921 could obviously decrease the expressions of mRNA and protein of CDX2 gene and down-regulate the expression of BCR-ABL fusion gene in the K562 cells, as well as enhance the effects of VCR on proliferation inhibition and inducing apoptosis of K562 cells.

山东省医药卫生科技发展计划资助项目（No.2014WS0183）；山东省自然科学基金资助项目（No.ZR2014HL032）