FIGURE 3.

Resistance to CDK4/6 inhibitors in breast cancer is promoted by CPVL by reducing PTEN. (a) Pathways correlating with CPVL determined by GSEA. Viability of MCF7‐R cells transfected with control or si‐CPVL and incubated with DMSO or SF1760 and gradient concentrations of palbociclib (b) or ribociclib (g). Western blots of CPVL, PTEN, p‐Rb, cyclin E1, and β‐Actin protein expression in MCF7‐R cells transfected with control or si‐CPVL and incubated with 10 μM palbociclib (c) or 15 μM ribociclib (h). MCF7‐R cells were transfected with control or si‐CPVL and incubated with DMSO or SF1760 and gradient concentration of palbociclib then colony formation (d), cell cycle distribution (e), and apoptosis (f) were evaluated. MCF7‐R cells were transfected with control or si‐CPVL, then colony formation (i), cell cycle distribution (j), and apoptosis (k) were evaluated. All values are shown as mean ± SD of three repeats of duplicates. *p < 0.01, **p < 0.001 vs. control