IGF-1 stimulates the inhibitory effect on a C/EBP consensus construct. A). To validate the activity of individual LIP and LAP2 constructs, a C/EBP consensus luciferase construct (500 ng) and a Renilla construct (20 ng) as internal control were co-transfected with LAP2 and LIP individually or together at different ratios into C/EBPβ null cells to a total of 2500 ng plasmid DNA. Control vector serves as both a control for basal activity and to match the quantity of plasmid DNA. Luciferase and Renilla activities were recorded at 48 hours. B). IGF-1 stimulation of MCF10A cells regulates C/EBPβ activity. MCF10A cells were transfected with a C/EBP consensus Luciferase construct (500 ng) and a Renilla construct (20 ng) as internal control and serum starved for 24 hours prior to treatment with 39 nM IGF-1. Luciferase activity was analyzed after 16 hours of treatment with IGF-1. The relative luciferase activity was calculated as Luciferase value/Renilla value (n = 5). Statistical significance was determined using an unpaired, 2-tailed T-test with a * p value < 0.05.