Kinetic parameters of DHEA metabolism by the investigated HGSOC cells. Km and Vmax values were calculated using GraphPad Prism 6.0 software following the incubation of the cell lines with increasing concentrations of DHEA (0 to 2000 nM) as a hormone precursor for 48 h. All data are presented as the means ± SD of three independent experiments. Values in bold and marked with an asterisk (*) are significantly different as compared with both carboplatin-sensitive cell lines 13363 and 13699 (p < 0.05). n.c., not calculable.