Positive regulation of cell migration and invasion by VASP via Rac1 pathway in human mammary epithelial cells

Abstract

Objective: To study the role of cytoskeleton associated protein vasodilator‐stimulated phosphoprotein (VASP) on migration of human mammary epithelial tumor cells and its mechanism. Methods: The expression level of VASP in HUMEC, MCF‐7 cells, MDA‐MB‐231 cells was detected by RT‐PCR and Western Blotting. The total Rac1 expression level was detected by Western Blotting and activities of Rac1 were examined by GST Pull‐down assays. The relatively high invasive MDA‐MB‐231 cells was intervened with Rac1 siRNA Expression Cassette segments. Accordingly the cells invasive migration ability was analyzed in wound‐healing assays (2D assays) and transwell invasion assays (3D assays). Results: Compared with HUMEC and MCF‐7cells, VASP was highest expressed in MDA‐MB‐231 cells at mRNA and protein level. Accordingly MDA‐MB‐231 cells revealed the highest invasive migration capacity in 2D and 3D assays. Rac1 siRNA Expression Cassette down‐regulated the mRNA and protein expression level of VASP, which caused a marked reduction in 2D and 3D migration capacity in MDA‐MB‐231 cells (P<0.01). Conclusion: The higher expression level of VASP contributed to higher invasive migration capacity of human mammary epithelial cells which was controlled by Rac1 pathway. (This work was supported by National Natural Sciences Foundation of China under Grant No.30770966)