(A) Inducible clonal T47D cells with mdm2 shRNA or control vector were treated with or without 4μg/ml doxycycline (dox) for 3 days, followed by 10nM estrogen for 5 days in the presence or absence of dox. A representative image of western blot analysis of MDM2, phospho Rb, E2F1, p53 and Actin protein levels from 50μg whole cell protein extract is shown. (B) ImageJ analysis was performed for MDM2, phospho Rb and E2F1 protein levels normalized to Actin. The graph represents an average of three independent experiments with standard deviation in inducible clonal T47D cells with mdm2 shRNA or control vector. (C) A constitutive pool of T47D cells with mdm2 shRNA or control vector were grown with or without 10nM estrogen for 5 days. A representative image of western blot analysis of MDM2, phospho Rb, E2F1, total Rb and Actin protein levels from 50μg whole cell protein extract is shown. (D) ImageJ analysis was performed for MDM2, phospho Rb and E2F1 protein levels normalized to Actin. Graph represents average of three independent experiments with standard deviation in constitutive pool of T47D cells with mdm2 shRNA or control vector. * represents a p-value ≤ 0.05, ** represents a p-value ≤ 0.01, *** represents a p-value ≤ 0.001. The p-value was determined by 2-tailed Student t-test.