RESUMO
OBJECTIVE: To explore the role of cortactin in endocytosis of colon cancer cells and clarify the significance of its over-expression in colon cancer tissues. METHODS: Immunohistochemistry and Western blot were employed to detect the expression of cortactin in benign and malignant tissues and cells. Cell endocytosis was examined in cancer cells after siRNA treatment and DNA transfection with plasmid encoding cortactin wild type and domain deletion mutants. RESULTS: Cortactin was over-expressed in colon cancer tissues than in adjacent normal tissues. The expression rate was 77.5% in cancer tissues and 47.5% in normal tissues (P < 0.05). The value of transferrin uptake was 0.61 ± 0.02 in siRNA treated cancer cells and 1.01 ± 0.16 in the control cells (P < 0.05). Intact molecule and sufficient level of cortactin was required for an optimal endocytosis of cancer cells. Cortactin was involved in coated-vesicle transportation in cells. CONCLUSION: Endocytosis in colon cancer cells is dependent on an intact expression of CTTN. An over-expression of cortactin facilitates the signaling in invasion and metastasis related to endocytosis.