Reactive oxygen species (ROS) are known to be involved in different pro- and anticarcinogenic mechanisms. However, their influence on the maintenance of the transformed phenotype has not been studied so far. Here we show that the anchorage-independent growth of transformed murine fibroblasts is inhibited by antioxidants and radical scavengers in a concentration-dependent and reversible manner. These agents also reduce TGF-beta-dependent stimulation of colony formation in soft agar, pointing to their specific interference with TGF-beta-triggered signal chains involved in the maintenance of the transformed state.
