RPS6KB1 and neoplasm: Blocking ATM activation with KU55933 markedly prevented the phosphorylation of ERK1/2 and p38, as well as mTOR, p70S6K, and 4E‐BP1 in senescent MCF7 and HCT116 tumor cells induced by citrate, suggesting that ATM signaling is upstream of MAPK and mTOR signaling pathways during citrate‐induced tumor cell senescence (Figure 7A).