Soluble Fibronectin Activates RhoA and Causes Cytoskeleton-related Changes of Cancer Cells

Abstract: It is well known that fibronectin within extracellular matrix can ligate membrane receptor integrin and induce RhoA mediated signals leading to reorganization of the cytoskeleton and regulation of cell migration. However， a big portion of fibronectin is dissolved in the plasma. Whether soluble fibronectin has similar effect needs to be elucidated. Here we show that adding soluble fibronectin to cell culture medium caused change of RhoA protein from inactive GDP-binding form to active GTP-binding form， with increased association with its substrate. Antibody against α₅β₁ integrin prevented the activation of RhoA protein. Soluble fibronectin induced F-actin formation of the cells. In human prostate cancer cell line PC-3， soluble fibronectin caused morphological change from polygonal to round and antibody against α₅β₁ integrin prevented the change. The results revealed that soluble fibronectin could bind α₅β₁ integrin and induce RhoA mediated signal transduction.
    

CSTR: 32200.14.cjcb.2007.02.0019