Decorin down-regulates β-catenin via the Met receptor. (A, top) Representative immunoblots of HeLa cells treated with 100 nM decorin for the times indicated and probed for β-catenin. Tubulin was used as a loading control. (bottom) Quantification of immunoblots as those presented in the top panel from three independent experiments. (B, top) β-Catenin levels after treatment with 100 nM decorin for 30 min in the presence or absence of 10 µM of the proteasome inhibitor lactacystin. Cells were preincubated with lactacystin for 1 h before adding decorin. (bottom) Quantification of immunoblots as those presented in the top panel from three independent experiments. (C, top) β-Catenin and PARP immunoblots after treatment with 100 nM decorin for 6 h in the presence or absence of the tyrosine kinase inhibitors AG1478 and SU11274 (both 1 µM) as indicated. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as loading control. (bottom) Quantification of immunoblots as those presented in the top panel from three independent experiments performed in triplicate. Values represent the mean ± SEM (*, P < 0.05; **, P < 0.01). All of the relative values were obtained by scanning densitometry (chemiluminescence). Values shown in blots are given in kiloDaltons.