Fig. 2

Cells cultivated in PDS secrete more proteins compared to monolayer cells and increase dedifferentiation. a Mammosphere formation of MCF7 and b MB-MDA-231 cells. Monolayer cells were treated with conditioned media from cells grown in the PDS model (n = 3) for 48 h and were then investigated for mammosphere forming capacity. Data were related to the 2D control. Mean ± SEM is shown. p* ≤ 0.05, p** ≤ 0.001, Student’s t-test. c Cell proliferation of MCF7 and d MB-MDA-231 cells were assessed by absolute cell number. Monolayer cells were treated with conditioned media from cells grown in the PDS model (n = 3) for 48 h and were then investigated for proliferation changes assessed by absolute cell number. Mean ± SEM is shown. p* ≤ 0.05, p** ≤ 0.001, Student’s t-test. e Venn diagram showing numbers of proteins secreted from MCF7 cells only in 2D (0), in 2D and the PDS model (32) and only in the PDS model (40). f Venn diagram showing numbers of proteins secreted from MDA-MB-231 cells only in 2D (0), in 2D and the PDS model (84) and only in the PDS model (37). g Schematic picture depicting all analyzed proteins (n = 184) secreted from cells in PDSs or from cells in both growth conditions or non-detectable proteins for MCF7s and MB-MDA-231s