Fig. 7.

P^182–195 inhibits Wnt signaling and blocks growth of colorectal cancer cells. a–e, g, m Luciferase activity (TOP/FOP) in SW480 cells transfected with indicated amounts of P^182–195 or the QV-PS mutated control (a, b) in SW480 cells which were untreated or treated with indicated concentrations of the synthetic peptides R₉ (control), P^182–195-R₉, or its QV-PS mutant (QV-PS-R₉) for 48 h (c), in SW480 cells transfected with P^182–195 together with siRNA against GFP (control) or against axin2 (d), in parental SW480 cells (WT #1) and two AXIN2 knockout clones (−/− #1, 2) which were untreated or treated with 0.1 µM P^182–195-R9 for 48 h (e), in parental SW480 cells (WT #1), a WT axin2 control clone (WT #2), and two axin2 QM-PS mutated clones (QM-PS #1, 2) transfected with P^182–195 (g), in SW480 cells transfected with P^182–195 and/or treated with 50 nM of the tankyrase inhibitor G007-LK overnight (m). Western blot below d shows efficient axin2 knockdown. Results are mean ± SEM (n = 5 [a, g], n = 4 [b, c, d], n = 3 [e, m]). f Western blot shows absence of axin2 in the AXIN2 knockout clones used in e. h Relative mRNA expression of the β-catenin target genes LGR5, MYC, and AXIN2 normalized to GAPDH in SW480 cells or SW480 AXIN2 knockout cells which were untreated or treated for 48 h with 10 µM of indicated peptides. Results are mean ± SEM (n = 3). i, k Cell colonies grown for 96 h from SW480 cells which were transfected with increasing amounts of P^182–195 or its QV-PS mutated analog together with GFP, sorted by GFP expression and sparsely plated (i), or from SW480 cells or SW480 AXIN2 knockout cells which were treated with 10 µM of indicated synthetic peptides (k). Cells were stained by ethidium bromide incorporation and visualized with UV light. Scale bar: 0.5 cm. j, l Automated quantification of colony numbers from three independent experiments as in i (j) or k (l). Results are mean ± SEM (n = 3). *p < 0.05, **p < 0.01, ***p < 0.001 (Student’s t-test). Given nanograms (ng) of the peptide refer to the transfection of a 12 well. Source data are provided as a Source Data file