Inhibition of human TCF4/ flag epitope-tagged beta-catenin (unknown origin) interaction transfected in human HCT116 cells after 24 hrs by beta-galactosidase/luciferase reporter gene assay
Inhibition of TCF-4 ( 1 to 56 residues) (unknown origin) binding to beta-catenin/armadillo (unknown origin) assessed as dissociation constant by ITC assay
Antagonist activity against TCF-4 ( 1 to 56 residues) (unknown origin) binding to beta-catenin armadillo repeat units (unknown origin) assessed as reduction in TCF4-beta-catenin binding at 50 uM at 20 degC by WaterLOGSY NMR screening method
Inhibition of TCF-4/beta catenin in human Tcf33.13 cells expressing Tcf-4/SV40 binding sites driving firefly luciferase reporter gene after 24 hrs by luminometer
Inhibition of TCF-4/beta catenin in human Tcf22C11 cells expressing Tcf-4/SV40 binding sites driving firefly luciferase reporter gene after 24 hrs by luminometer
AlphaScreen Assay: Experiments were performed in white opaque 384-well plates from PerkinElmer (Waltham, Mass.), and the samples were read on a Synergy 2 plate reader (Biotek, Winooski, Vt.) with a sensitivity setting of 200 using AlphaScreen protocol with excitation at 680 nm and emission at 570 nm. All dilutions were made in 1× assay buffer containing 25 mM HEPES (pH 7.4), 100 mMNaCl and 0.1% BSA to minimize nonspecific interactions. For inhibitor competition experiment, 5 nM of C-terminal biotinylated Tcf4 45-mer, 20 nM of N-terminal His6-tagged β-catenin and inhibitors at different concentration were incubated in 20 μL of assay buffer for 2 h. Donor and acceptor beads were added to a final concentration of 10 μg/mL in 25 μL of assay buffer. The mixture was incubated at room temperature for 1 h. For each inhibitor competition assay, the negative controls (equivalent to 0% inhibition) refer to 5.0 nM of biotinylated Tcf4 45-mer, 20 nM of β-catenin, 10 μg/mL donor and acce
Fluorescence Polarization (FP) Assay: Experiments were performed in 96-well Microfluor 2 black plates (Waltham, Mass.), and the samples were read by a Synergy 2 plate reader (Biotek, Winooski, Vt.). The fluorescence polarization (FP) was measured at room temperature with an excitation wavelength at 485 nm and an emission wavelength at 535 nm. The FP saturation experiment was performed in an assay buffer of 137 mM of NaCl, 2.7 mM of KCl, 10 mM of Na2HPO4, 2 mM of KH2PO4, 100 ug/mL of bovine gamma globulin, and 0.01% Triton-X 100. The final reaction volume is 100 uL. The competitive FP assays used 2.5 nM of Tcf4 fluorescence tracer, 10 nM of β-catenin, and different concentrations of the tested inhibitors in 100 uL of assay buffer. Each assay plate was covered black and gently mixed on an orbital shaker for 3 h to reach equilibrium before polarization values were read. For each inhibitor competition assay, the negative controls (equivalent to 0% inhibition) refer to 2.5 nM of Tcf4 fluorescence tracer and 10 nM of β-catenin, but no tested peptide inhibitor was presented. The positive controls (equivalent to 100% inhibition) refer to only 2.5 nM of Tcf4 fluorescence tracer in a final volume of 100 uL.