Nkx2．2对髓母细胞瘤细胞恶性表型的调控作用

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。

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

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 cells 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 cerebel?la 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.