Western blot analyses of GBM cells cultured with serum-free medium. Cells were grown as described in Methods section and the lysate proteins were subjected to SDS-PAGE. The sample was subjected to immunoblot analysis with caveolin-1 mouse monoclonal antibody (4 H312, sc-70516; Santa Cruz Biotech) probe. Note that anti-Caveolin-1 mAb specifically binds to Caveolin-1 isoforms (21–24 kDa) while anti-β-Actin antibody specifically recognizes β-Actin (42 kDa). These results further demonstrate that Caveolin-1 is present at both the protein level and mRNA level (Figure 8).