Ionizing radiation–induced MEK and Erk activation does not enhance survival of irradiated human squamous carcinoma cells

Purpose: Ionizing radiation (IR) triggers several intracellular signaling cascades that have commonly been regarded as mitogenic, including the Raf–MEK–Erk kinase cascade. In addition to promoting proliferation, activated MEK and Erk may also prevent cell death induced by cytotoxic stimuli. Because Raf, MEK, and Erk are activated by IR in some tumor cell lines, this suggests that IR-induced activation of the kinase cascade may enhance the survival of irradiated cells.