Fig. 5.

Skp2 antagonizes the tumor suppression function of FOXO1. (A and B) LNCaP cells were cotransfected with pEGFP vector along with control vector pcDNA3.1, wild-type FOXO1, or two mutants FOXO1-S256A and FOXO1-AAA in the presence or absence of Skp2. At 48 h after transfection, transfected viable cells were photographed under both UV and transmitted light (A) and quantified by using trypan blue (B). (C and D) 786-O cells were cotransfected with pEGFP vector along with control vector pcDNA3.1, wild-type FOXO1, or Skp2. At 48 h after transfection, cells were fixed briefly with formaldehyde and subjected to two-color FACS analysis for cell cycle distribution (C) and lysed for immunoblotting with FOXO1 and Skp2 antibodies (D).