Inhibition of ERK activation enhances the repair of double-stranded breaks via non-homologous end joining by increasing DNA-PKcs activation

► Enhancing ERK activation reduces repair of ETOP-induced DSBs and DNA-PK activation. ► Inhibition of ERK activation sensitizes these processes. ► ERK reduces DNA-PK-mediated NHEJ. ► ERK facilitates cells to choose whether to repair DSBs via NHEJ.