Differential phosphorylation of PI3-kinase/Akt pathway during IR response in apoptosis-resistant ALLs. (A) Increased phosphorylation at 0 hours, 30 minutes, and 4 hours after IR of DNA-PK at serine 2056, Akt at serine 473, and ribosomal protein S6 at serine 235/6 in apoptosis-resistant ALL tumors (102, 106, and 111) compared with the representative apoptosis-sensitive tumor ALL 114. (B) Comparable phosphorylation of Bad at residues serine 112 and 136 and expression of PTEN protein at 0 hours, 4 hours, and 8 hours after IR in apoptosis-resistant ALL tumors (102, 106, and 111) compared with the representative apoptosis-sensitive tumor ALL 114. Numerical values represent expression ratios of the phosphorylated-total protein for DNA-PK_CS, Akt, S6, and Bad, and protein/actin for PTEN. R indicates apoptosis-resistant ALL; S, apoptosis-sensitive ALL.