Fig. 4

VAMP3 overexpression induces autophagy and reduces PTX sensitivity of TNBC cells. MDA-MB-231/PTX, MDA-MB-468/PTX, and MDA-MB-453/PTX cells stably transfected with sh-CEBPD were further administered oe-VAMP3. A mRNA and protein levels of VAMP3 in cells determined by qPCR and WB assays (n = 3). These cells were further treated with the autophagy antagonist CQ. B autophagy activity in cells analyzed by immunofluorescence staining of LC3; C viability of cells and the IC50 of PTX examined by CCK-8 assay (n = 3). These cells were additionally treated with 15 nM PTX for 48 h, D colony formation ability of cells analyzed by colony formation assay (n = 3); E apoptosis of cells determined by flow cytometry (n = 3); F migration and invasion of cells determined by Transwell assay (n = 3). Differences were analyzed by two-way ANOVA, followed by Tukey's (B, D-F) or Sidak's (A) post-hoc tests. IC50 of PTX to cells was analyzed by nonlinear fitting analysis (C). *p < 0.05