MCL1 and glioblastoma: Overexpression of Bcl-xL (S62A) or Mcl-1 (T92A) mutants partially rescued ABT-263-enhanced apoptosis in shKPNB1 U87 and U251 cells (Fig. 4g, h), suggesting that KPNB1 deficiency sensitizes glioblastoma cells to ABT-263 in a Bcl-xL/Mcl-1-dependent manner.