Figure 7.

The absence of caveolin-1 diminishes PTEN activity and enhances Akt activity while promoting exaggerated proliferation and resistance to apoptosis. Caveolin-1–null cells were infected with an adenoviral vector containing wither wild-type caveolin-1 (Cav-1 Null Ad-GFP) or empty vector (Cav-1 Null Ad-Cav-1). PTEN activity (A) and the level of phosphorylated Akt (B) were assessed 48 hours after infection. C: Caveolin-1–null fibroblasts and wild-type fibroblasts were plated on either tissue culture plates (TC) or polymerized collagen (PC) in growth factor–replete media and cell number determined as a function of time. D: Caveolin-1–null fibroblasts were infected with an adenoviral vector containing dominant negative Akt or empty virus and cultured in the presence of media containing 10% serum. The levels of phospho-Akt and cleaved caspase 3 were examined by Western analysis. E and F: The proliferation of caveolin-1–null cells expressing DN-Akt or GFP-control was quantified by assessing cell number at 24, 48, and 72 hours postinfection (E) or by BrdU uptake at 72 hours (F). Error bars represent SEM. Data are representative of three independent experiments.