Fig. 7

Cytostatic treatment leads to enhanced ABCB5-signals in keratinocytes and external melanoma cells. Tri-culture spheroids were generated by 3D cultivation of CCD-1137Sk cells for three days, followed by the combined addition of HaCaT and SK-MEL-28 cells. HaCaT cells were labeled with CellTrackerRed CMPTX dye and SK-MEL-28 cells with CellTrackerGreen CMFDA dye. After another two days, tri-culture spheroids were treated with 0.01 ‰ of DMSO as control (a-c) or 100 nM docetaxel in DMSO (d-f) for 48 h. Spheroids were cryosectioned into 10-μm thick slices and immunostained for mouse anti-ABCB5 from TICEBA. a and d Overlay images of the confocal sections shown in b and e. In overlays, ABCB5 signals, melanoma cells, keratinocytes, and nuclei are depicted in red, green, yellow, and blue, respectively. Scale bars: 100 μm. c and f Detail images of ABCB5 signals from boxed regions in b and e. g-h Quantification of the relative intensity of ABCB5-positive external (g) and internal (h) SK-MEL-28 cells (percentage of total). Given is mean ± SEM (n = 4 independent experiments; * P < 0.05, ** P < 0.01). For each experiment, ≥ 3 spheroids were analyzed