Selective Inhibition by Apocynin of the Proliferation and Adhesion to Fibronectin of v-H-<i>ras</i>-Transformed 3Y1 Cells

We determined the effects of apocynin, a representative inhibitor of NADPH oxidase, on the proliferative and adhesive properties of 3Y1 rat fibroblasts and the 3Y1 v-H-ras-transformed derivative, HR-3Y1-2. Apocynin inhibited the proliferation of HR-3Y1-2 but not 3Y1 cells at 10 µM and 100 µM. Apocynin also decreased the intracellular reactive oxygen species (ROS) level in HR-3Y1-2 but not 3Y1 cells. We also evaluated the effects of apocynin on cell adhesion to fibronectin and found decreased adhesion of HR-3Y1-2 cells to fibronectin-coated plates. Our results indicate that apocynin selectively down-regulated β1-integrin cell surface expression on the HR-3Y1-2 cells. It also inhibited the migration and invasion of these cells. These data suggest that reducing the production of NADPH oxidase-mediated ROS could be an effective means for ameliorating the abnormal growth, adhesion and motility of v-H-ras-transformed cells.