Figure 1.

Generation and characterization of PDE4 inhibitor payload drug. (a) GSK256066 and its derivative linker analogs. (b) PDE4B enzymatic activity inhibition by a range of concentrations of compound 1 to 6 was assessed. (c) THP-1 cells stably transfected with CRE-Luc (THP-1 CRE-Luc cells) were treated with a range of concentrations of compound 1 to 6 for 6 hours, CRE-Luc activity by a range of concentrations of compound 1 to 6 was assessed. (d) THP-1 CRE-Luc cells were treated with a range of concentrations of compound 1 to 6 for 24 hours, and the cell viability was assessed. (e) PDE4B inhibition IC₅₀ of assay (b) and CRE-Luc activity EC₅₀ of assay (c) of compound 1 to 6 was calculated. Results in (b–d) are presented as means ± SD.