NUAK1增加乳腺癌细胞的趋化和粘附能力

本课题组先前已证明NUAK1/ARK5可通过影响F-actin的聚合从而促进乳腺癌细胞的侵袭和转移. 但是NUAK1是否还通过其它机制影响乳腺癌的侵袭和转移尚有待于探讨.本文证明NUAK1还可以影响乳腺癌细胞趋化、粘附能力从而在乳腺癌细胞侵袭转移中起重要作用. 应用化学合成的小RNA干扰质粒转染到乳腺癌细胞系MDA MB 231中，用免疫印迹技术检测NUAK1蛋白的表达情况. 结果显示,在敲除NUAK1的细胞（siNUAK1/MDA231）中, NUAK1蛋白表达水平明显降低；趋化运动实验结果显示, siNUAK1/MDA231细胞的趋化运动能力比未处理组（Scr/MDA231）细胞明显降低；细胞粘附实验结果显示, EGF刺激5 min、15 min后,siNUAK1/MDA231细胞比Scr/MDA231细胞粘附细胞数量均明显减少；免疫印迹技术检测integrin β1磷酸化验证NUAK1影响乳腺癌细胞粘附的机制. 结果显示,siNUAK1/MDA231细胞内integrin β1磷酸化比Scr/MDA231细胞不同程度降低. 上述结果表明, NUAK1通过磷酸化integrin β1促进乳腺癌细胞与纤维粘连蛋白的粘附，从而促进乳腺癌的侵袭和转移.

NUAK1 Promotes Chemotaxis and Adhesion of MDA-MB-231 Breast Cancer Cell

Previous studies suggested that NUAK1/ARK5 induced F-actin polymerization to promote the migration and invasion of breast cancers. However, the complete understanding of NUAK1 effects on invasion and metastasis remains elusive. Here we reported that NUAK1 affected the chemotaxis and adhesion of breast cancer cells. The siRNA plasmid was transfected into MDA MB 231 cells, the NUAK1 expression and the phosphorylation of integrin β1 were detected by Western blot, and chemotaxis assays were performed. The results showed that the NUAK1 protein level was reduced after RNAi, and decreased chemotaxis ability was observed compared with the transfections of scramble control. In additional adhesion assays, the number of adhesive cells at 5 and 15 min were significantly lower in siNUAK1transfected cells than those of the controls. Inhibition of integrin β1 phosphorylation was observed in siNUAK1/MDA 231 cells. This study suggested that the induction of NUAK1 in cell invasion and metastasis might involve the changes in chemotaxis and adhesion