Fig. 1

Different mammary cells respond to stimulation with LPA 18:1 but express a different LPAR profile: (a/b) Mean relative LPAR mRNA expression. Values are calculated using the 2^-ΔCq method, the reference is HPRT; (a) LPAR mRNA profile of ADSCs, MES and HMEC/BCC from tumors and healthy tissue; (b) The effect of adipogenic differentiation (Diff) on the LPAR mRNA profile of ADSCs compared to the control (CTL). (c) The effect of LPA on cytosolic free calcium levels; x-axis shows the molarity of LPA 18:1 in a common logarithmic scale, y-axis shows the maximal ratio of the emission of Fura-2 (340 nm/380 nm excitation). The mean measuring points with the SD are plotted and connected with a nonlinear fit (variable slope) using GraphPad Prism 7.00, epithelial cells have a significantly higher calcium release than ADSCs and mesenchymal cells at concentrations of 1 μM LPA and above (not plotted for clarity, p < 0.0167, Kruskal–Wallis H test, Mann–Whitney U test with Bonferroni correction); abbreviations: healthy h, tumor-distant td, tumor-adjacent ta, tumor t, EpCAM-positive breast cancer cells BCC; n = 4