Fig. 4

Effect of cholesterol depletion on the protein levels and activity of ADAM17 in p95HER2-induced senescent cells. a MCF7 Tet-Off p95HER2 cells were cultured with or without doxycycline for 5 days and further incubated in serum-free media with or without 1 mM MβCD for 2 additional days. Then cells were stained with filipin. Representative bright-field and filipin staining images are shown. b The same cells as in (a) were treated with different concentrations of MβCD. Control and treated cells were harvested and lysed, and cell lysates were analyzed by Western blot with the indicated antibodies. The densitometric quantification of three independent experiments is expressed as average ± standard deviation. *P <0.05 using the two-sided Student’s t test. c MCF7 Tet-Off p95HER2 or MCF10A Tet-On p95HER2 cells expressing AP-tagged TGF-α (left panels), Areg (middle panels), or BTC (right panel) were treated with or without doxycycline and MβCD or vehicle for 48 h as indicated. AP was quantified in serum-free conditioned media and cell lysates. Data shown represent the averages and standard deviations of three independent experiments. *P < 0.05 using the two-sided Student’s t test. AP alkaline phosphatase, BTC betacellulin, Doxy doxycycline, MβCD methyl-beta-cyclodextrin, TGF transforming growth factor