Fig. 3

Docetaxel treatment reduces the amounts of proliferating cells in melanoma 3D tri-cultures. Tri-culture spheroids were produced by 3D cultivation of fibroblasts for three days, followed by simultaneous addition of keratinocytes and melanoma cells. HaCaT cells and SK-MEL-28 cells were labeled with CellTrackerRed CMPTX dye and CellTrackerGreen CMFDA, respectively. After another cultivation period of two days, tri-culture spheroids were treated with 0.01 ‰ of DMSO as control or 100 nM docetaxel for 15, 24, 48, and 72 h. Spheroids were cryosectioned into 10-μm thick slices and stained for Ki67. a and b Representative confocal images of control (a) and docetaxel-treated cultures (b). In overlay images, Ki67 immunostaining signals, SK-MEL-28, HaCaT, and nuclei are depicted in red, green, yellow, and blue, respectively. Scale bars: 100 μm. c Quantification of Ki67-positive cells. Graph displays the amounts of Ki67-positive cells as mean ± SEM (n ≥ 3 independent experiments; ** P < 0.01) in percent of the whole cell count per slice. For each experiment and time point, ≥ 3 spheroids were analyzed