Attenuated endocytosis by down-regulation of cortactin protein in cancer cells / 基础医学与临床

ABSTRACT

Objective To study cortactin function in cancer cell endocytosis.Methods We applied cortactin siRNA interference to MDA-Mb-231,a human breast adenocarcinoma cell line in which cortactin was over-expressed,and introduced anti-cortactin immunoreagents into the cells with BioPorter system to interfere with cortactin function in vivo.Capture-ELISA assay was used to measure transferrin uptake.We used immunoblot assay to assess the effect of cortactin knock-down and immunoflurescence microscopy to examine the effect of cortactin down-regulation on transferrin uptake.Results Interference of cortactin function in cells resulted in impairment of transferrin endocytosis.Transferrin fluorescent intensity in cytoplasm in cortactin siRNA treated-cells was significantly reduced in comparison to that of mock-treated cells.Less than 50% of cells subjected to cortactin siRNA treatment had normal transferrin uptake.Endocytosis in MDA-Mb-231 cells introduced with cortactin antibodies was impaired as well,showing a 30%～ 60% reduction in transferrin uptake.Conclusion Crtactin,an actin-binding protein,plays an essential role in cell endocytosis.