Fig. 4
PEG10 suppresses natural cell cycle inhibitor p21 and EMT process inhibitor SIAH1. A Immunoblot showed changes in the cell cycle-related protein p21 and ubiquitin-related protein SIAH1 expression in parental (MCF7 and T47D) versus palbociclib-resistant (MCF7-PR and T47D-PR) cells. B, C Immunoblot showed p21 and SIAH1 protein expression level after the transient PEG10 knockdown by using PEG10 siRNA or PEG10-ASO. D, E Cell viability (MTT) assay of MCF7-PR and T47D-PR cells before and after ectopic overexpression of p21 and subsequent treatment with the various concentrations of palbociclib for 72 h. Three independently repeated experiments were performed with similar results. Independent sample t-test: *p < 0.05, **p < 0.01, ***p < 0.001, Abbreviation: ns, not significant. F, G Cell viability (MTT) assay of MCF7-PR and T47D-PR cells before and after ectopic overexpression of SIAH1 and subsequent treatment with the various concentrations of palbociclib for 72 h. Three independently repeated experiments were performed with similar results. Independent sample t-test: *p < 0.05, **p < 0.01, ***p < 0.001, Abbreviation: ns, not significant. H Immunoblot showed the depletion of cyclins (cyclin E, cyclin D1, and cyclin A) and CDK2 after the ectopic overexpression of p21 in MCF7-PR and T47D-PR cells. I Immunoblot showed the differential expression of cyclins (cyclin E, cyclin D1, and cyclin A) and CDK2 in parental cells (MCF7 and T47D) versus palbociclib-resistant cells (MCF7-PR and T47D-PR), respectively. J Immunoblot showed the depletion of cyclins (cyclin E, cyclin D1, and cyclin A) and CDK2 after PEG10 knockdown by PEG10 siRNA in MCF7-PR and T47D-PR cells. K, L Immunoblot showed the expression of ZEB1 and E-cadherin after the ectopic overexpression of p21 and SIAH1 in MCF7-PR and T47D-PR cells