Western-blotting analysis of Hsp90 client proteins and F-box protein S-phase kinase 2 (Skp2) in AT13387-treated C666-1. (A) Expression of senescence and cell cycle associated Hsp90 client proteins in C666-1 after 72 hrs and 96 hrs AT13387 treatment. (B) Knockdown of Skp2 by siRNA leaded to upregulation of p27 in C666-1. (C) Downregulation of p-AKT (Ser473) and Skp2 by AKT inhibitor. (D) Downregulation of Skp2 and Hsp90 client oncoproteins AKT, p-AKT (Ser473), EGFR, and p-STAT3 after AT13387 treatment. Value represented the arbitrary unit of band intensity after normalization with β-actin.