稳定转染NOR1抑制5-8F细胞片状伪足形成和Wnt信号通路

NOR1 Regulates Morphogenetic Cell Behavior in vitro Coincident With Inhibition of a Non-canonical Wnt-signaling Cascade

细胞骨架是真核细胞中的蛋白纤维网络结构,不仅与保持细胞形态结构有关,而且影响细胞黏附和细胞运动.NOR1是从鼻咽癌中克隆得到的新基因,在鼻咽癌组织和细胞系中表达下调.本研究建立了NOR1稳定表达的鼻咽癌5-8F细胞系.过表达NOR1引起高转移性鼻咽癌5-8F细胞形态改变,抑制片状伪足形成、细胞表面积缩小、细胞聚集性增强.扫描电镜检测发现,NOR1抑制了5-8F细胞膜微绒毛的数量,引起细胞膜表面改变.细胞骨架染色发现,NOR1过表达导致5-8F细胞actin骨架连续性破坏,应力纤维增加.Realtime RT-PCR检测发现,NOR1引起5-8F细胞Wnt/β-catenin信号通路分子Wnt5A受体FZD5、FZD7表达下调,抑制了β-catenin蛋白入核.提示NOR1抑制Wnt/β-catenin信号通路激活,破坏细胞骨架连续性,抑制细胞膜微绒毛与伪足形成.

Oxidored-nitro domain containing protein 1 （NOR1） is a candidate tumor suppressor gene that is down-regulated in nasopharyngeal carcinoma （NPC）. In the present study, NOR1 stable transfected NPC 5-8F cells were established. As a result, the 5-8F cells expressing NOR1 showed dramatic morphological changes comparing with the control, such as less lamellipodia protrusions and membrane ruffles at the periphery of the cells. Ectopic expression of NOR1 in NPC 5-8F cells also inhibited microvillus formation on the surface of tumor cells due to filamentous actin rearrangement. Further more, realtime RT-PCR assay revealed that ectopic expression of NOR1 suppressed the expression level of FZD5 and FZD7, and then attenuated β-catenin nuclear translocation. This first report provides experimental proof to probe the function of NOR1 gene in the process of lamellipodia formation and the Wnt signaling in NPC cells.