Nkx2．2对髓母细胞瘤细胞恶性表型的调控作用

Regulatory Effect of Nkx2. 2 on Malignant Phenotype of Medulloblas-toma Cells

目的：探究转录因子NKX2．2（NK2 homeobox 2）在小鼠髓母细胞瘤（medulloblastoma， MB）中的表达及其对人源MB细胞系Daoy增殖、迁移能力的影响。方法采用实时定量PCR检测Nkx2．2在MB和野生型小鼠小脑组织中mRNA水平的表达差异，并通过免疫组化进一步检测其差异；设计针对Nkx2．2的小干扰RNA，分别通过实时定量 PCR 和 Western 印迹检测 Nkx2．2的干涉效率；干涉 Daoy 细胞中的Nkx2．2后采用CCK？8、平板克隆形成实验检测Nkx2．2基因沉默对Daoy细胞增殖和迁移能力的影响，流式细胞术检测细胞凋亡，划痕实验评价细胞迁移能力。结果 NKX2．2在小鼠MB中的表达明显低于正常组织；沉默Nkx2．2能显著促进MB细胞的增殖且抑制其凋亡，但不影响细胞迁移。结论 Nkx2．2能抑制MB细胞的增殖并促进其凋亡，其下调可能参与MB的发生。

Objective To examine the expression of NK2 homeobox 2 （ NKX2. 2 ） in mouse medulloblastoma （MB） and its regulatory role in the growth and migration of a human MB cell line, Daoy. Methods Quantitative RT-PCR （qRT-PCR） was used to examine and compare Nkx2. 2 expression in the cerebella of MB and wild-type mice; Nkx2.2 was silenced in Daoy ceils by siRNA, which was followed by the measurement of cell proliferation via CCK8 and plate colony formation assays, serum starvation-triggered apoptosis via flow cytometry, and in vitro migration ca- pacity through wound-healing test. Results NKX2.2 was significantly downregulated in the cerebella of MB mice compared with that in wild-type mice. Knockdown of Nkx2. 2 in Daoy cells promoted proliferation and inhibited serum withdrawal-induced apoptosis, but failed to affect cell migration capability. Conclusion Nkx2. 2 inhibits the proliferation of MB cells and promotes their apoptosis, suggesting the possible involvement of Nkx2. 2 downregulation in MB development.