Reactive oxygen species (ROS) have recently drawn significant attention as putative
mitogenic mediators downstream of activated growth factor receptors and oncogenic Ras;
however, the possibility that a redox-related mechanism also operates in the negative
control of cell proliferation by inhibitory signals has not been investigated thus far. Here we
show that the arrest of growth induced by cell confluence (" contact inhibition") is due, at
least in part, to a decrease in the steady-state levels of intracellular ROS and the consequent …