Fig. 4

Fulvestrant potentiates MDM2 inhibition in a fulvestrant-resistant cell line model. a Growth inhibition of MCF-7 FasR relative to vehicle with escalating doses of NVP-CGM097 in the presence (purple) or absence (red) of 100 nM fulvestrant—the dose used to generate the resistant cell line. No significant difference was observed after 48 h of treatment. b Flow cytometric quantification of propidium iodide incorporation into DNA compared to vehicle in MCF-7 FasR after incubation for 48 h with vehicle (0.01% DMSO), 1 μM NVP-CGM097, 100 nM fulvestrant, or the combination of both drugs. Statistical significance from χ² test using the vehicle-treated profile as the expected value is indicated. Red = G₁ (bottom), blue = S (middle), green = G₂/M (top). c Western blot analysis of the p53 transcriptional target p21 in MCF-7 FasR cells after 48 h incubation with 1 μM NVP-CGM097. α-tubulin staining is shown as an indication of relative loading. See Fig. S4B for full gel and blot images. d Representative images of MCF-7 FasR cell cultures after exposure to vehicle (0.01% DMSO) or 1 μM NVP-CGM097 for 48 h followed by staining for senescence-associated β-galactosidase. Bar = 20 μm e Quantification of MCF-7 FasR cells staining positive for senescence-associated β-galactosidase activity after treatment for 48 h with vehicle (0.01% DMSO, grey), 1 μM NVP-CGM097 (red), 100 nM fulvestrant (blue) or the combination of NVP-CGM097 and fulvestrant (purple). Statistical significance from Tukey’s multiple comparison test is indicated above each column