Figure 4.

PARP inhibition reduces E₂-induced IGF-1R. a MCF-7 cells were treated with E₂ for 48 h in the absence or presence of 1 or 2 μM of the IGF-1R inhibitor AG1024 after which protein extracts were prepared and subjected to immunoblot analysis with antibodies to PDZK1 or GAPDH. b Cells were treated with E₂ for 48 h in the absence or presence of increasing concentrations of TIQ-A. Protein extracts were prepared and subjected to immunoblot analysis with antibodies to IGF-1R or GAPDH. c MCF-7 cells were treated with E₂ for 24 h in the absence or presence of 0.5, 1, 2 or 5 μM TIQ-A. Total RNA was prepared and subjected to reverse transcription followed by conventional PCR with primers specific to human IGF-1R or β-actin. d MCF-7 cells were transduced with a viral vector encoding control shRNA or a shRNA targeting human PARP-1. Cells were then treated with E₂ for 48 h after which protein extracts were prepared and subjected to immunoblot analysis with antibodies to PARP-1, PDZK1, IGF-1R, or GAPDH. The dashed line indicates that the lane was cut from the same blot.