NUAK1通过影响F-actin聚合促进乳腺癌的侵袭转移

本课题组先前研究证明NUAK1/ARK5参与乳腺癌、胶质瘤侵袭转移，但机制尚不清楚.本文证明，NUAK1通过影响F-actin聚合促进乳腺癌的侵袭转移.应用小RNA干扰技术敲除乳腺癌细胞系MDA-MB-231中的NUAK1，用G418进行稳定筛选，并用Western印迹进行蛋白质表达检测，结果显示，成功敲除MDA-MB-231细胞中的NUAK1；采用Transwell侵袭实验检测NUAK1在乳腺癌细胞侵袭转移中的作用，结果表明，NUAK1被干扰的SiNUAK1/MDA-231细胞的侵袭能力明显减弱；应用免疫荧光法对细胞的F-actin进行荧光染色，半定量F-actin聚合分析结果显示，IGF-1在转染空载的细胞组（Scr/MDA-231）能诱导肌动蛋白短暂的聚合反应，而在敲除NUAK1的细胞组（SiNUAK1/MDA-231）肌动蛋白的聚合显著减少；用细胞因子IGF-1刺激乳腺癌细胞观察cofilin磷酸化，结果显示，在敲除NUAK1的细胞组（SiNUAK1/MDA-231），IGF-1诱导的cofilin的磷酸化明显受抑制.上述结果表明，NUAK1能通过促进F-actin的聚合从而影响乳腺癌细胞的侵袭转移.

NUAK1 Induces Migration and Invasion in Breast Cancer Through F-actin Polymerization

Previous studies suggested that NUAK1/ARK5 participated in the invasion and metastasis in breast cancer and glioma, but the molecular mechanism remains elusive. For the first time, we report that NUAK1 induces breast cancer cell invasion and metastasis though affecting F-actin polymerization in breast cancer cells. siRNA plasmid was used to transfect MDA-MB-231 cells. G418 was used to screen cell clones stably expressing NUAK1. Western blot was carried out to detect NUAK1 expression and the phosphorylation of cofilin in breast cancer cells with IGF-1 stimulation. The results showed the successful knockdown NUAK1 in MDA-MB-231 cells. Transwell invasion system was used to detect the role of NUAK1 in invasion of breast cancer and the results showed that the invasive capacity was lower in SiNUAK1/MDA-231 cells. Immunofluorescence staining was used to detect F-actin polymerization. The F-actin fluorescence assay results showed that IGF-1 induced an increase in F-actin content in Scr/MDA-231 cells, but not in SiNUAK1/MDA-231 cells. The phosphorylation of cofilin was obviously inhibited in SiNUAK1/MDA-231 cells. NUAK1 can induce migration and invasion of breast cancer through inducing F-actin polymerization.