Fig. 5: CDK4/6-mediated USP51 phosphorylation regulates ZEB1 protein degradation and cancer metastasis.
From: CDK4/6 inhibition blocks cancer metastasis through a USP51-ZEB1-dependent deubiquitination mechanism
a Western blotting of ZEB1 protein expression in MDA-MB-231 and SUM-159 cells overexpressing wild-type USP51 or two mutants (S26A-USP51 and S26D-USP51) of USP51 after treatment with palbociclib. b Coimmunoprecipitation analysis of ZEB1 protein ubiquitination in MDA-MB-231 and SUM-159 cells overexpressing wild-type USP51 or two mutants (S26A-USP51 and S26D-USP51) of USP51 after treatment with palbociclib. The cells were treated with MG132 for 12 h prior to harvest. c Western blotting of EMT markers in MDA-MB-231 and SUM-159 cells overexpressing wild-type USP51 or two mutants (S26A-USP51 and S26D-USP51) of USP51 after treatment with palbociclib. d, e Transwell migration (d) and wound-healing (e) assays in MDA-MB-231 and SUM-159 cells overexpressing the wild type or two mutants (S26A-USP51 and S26D-USP51) of USP51 by treatment with palbociclib. Scale bars, 100 μm. *P < 0.05, **P < 0.01 vs. respective control by unpaired Student’s t-test. f 3D outgrowth invasion assay in MDA-MB-231 cells overexpressing the wild type or two mutants (S26A-USP51 and S26D-USP51) of USP51 after treatment with palbociclib. Scale bars, 20 μm. *P < 0.05, **P < 0.01 vs. respective control by unpaired Student’s t-test. g, h Representative images and the quantification of lung nodules of BALB/c nude mice that were injected with MDA-MB-231 cells overexpressing wild-type USP51 or two mutants (S26A-USP51 and S26D-USP51) of USP51 after treatment with palbociclib. Scale bars, 100 and 20 μm. *P < 0.05, **P < 0.01 vs. respective control by unpaired Student’s t-test.
