Tyrosine 23 Phosphorylation of Annexin A2 Promotes Proliferation, Invasion, and Stat3 Phosphorylation in the Nucleus of Human Breast Cancer SK-BR-3 Cells

OBJECTIVE: To investigate the role of tyrosine 23 (Tyr23) phosphorylation of Annexin A2 (Anxa2) in regulating the proliferation and invasion of human breast cancer SK-BR-3 cells. METHODS: A panel of lentivirus plasmids expressing Anxa2-wide type (Ana2-WT), Anxa2-Y23A, and Anxa2-Y23D was generated and infected with SK-BR-3 cells. The monoclonal strains were screened. The expression of Anxa2-WT, Anxa2-Y23A, and Anxa2-Y23D was determined by Western blot analysis. The ability of the cells to proliferate was detected through an MTT [3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] test. Boyden chamber assays were employed to examine migration and invasion abilities. The interaction between Anxa2 and Stat3 was analyzed by immunoprecipitation analyses. Nucleoprotein and cytosolic protein were extracted from SK-BR-3, Anxa2-WT, Anxa2-Y23A, and Anxa2-Y23D cells to analyze the expression and localization of Stat3 phosphorylation. RESULTS: The monoclonal strains constitutively expressing Anxa2-WT, Anxa2-Y23A, and Anxa2-Y23D were screened. Both Anxa2-WT and Anxa2-Y23D enhanced the proliferation, migration and invasion abilities of SK-BR-3 cells (P<0.05). Immunoprecipitation analysis revealed that Anxa2 and Stat3 interacted with each other, and the expression of Stat3 phosphorylation in the nucleus was enhanced by Anxa2-Y23D. CONCLUSIONS: Tyr23 phosphorylation of Anxa2 promotes the proliferation and invasion of human breast cancer SK-BR-3 cells and the phosphorylation of Stat3 in the nucleus.