Fig. 4

SU112747 mediated bioenergetic alterations. a Melanoma cells Rel3 were serially passaged in spheroid culture conditions. Cumulative cell numbers were counted from the number of expanded cells and the inoculum used for each passage. There was a significant difference between the number of cells in SU11274-treated versus untreated cultures with a substantial inhibition of the cell proliferation with 1 μM SU11274. Melanoma cells could be serially propagated the presence of inhibitor (≥10 passages), thus demonstrating that SU11274 does not compromise long-term proliferation potential in vitro. b Rel3 cells from the spheroid cultures were trypsinized and plated in adherent culture conditions. Long-term propagation with or without SU11274 shifted cellular morphology from irregular spiked shape to flatter cobblestone morphology and less scattered colonies. c Two independent methods were compared to evaluate effect of the treatment with 1 μM SU11274 for 6 days on cell proliferation. Luminescent ATP-based assay has shown 9.4 % inhibition only in contrast to the 39.5 % inhibition of proliferation as determined by relative BrdU incorporation assay. d M14, EGFP-A375 and Rel3 cells were treated with 1 μM SU11274 in spheroid conditions for 7 days. Spheroids were trypsinized, viable cell counts determined, cell suspension was mixed with the luminescent reagent from the Luminescent ATP-based Assay and relative ATP-production per 100,000 cells was calculated at least in quadruplicates. SU11274 treatment significantly increased the relative ATP-content per cell in comparison to untreated controls. e–f Same treatments as in Fig. 4d. were used to determine glucose uptake and lactate release by colorimetric method. Values were expressed as mean + SD, there was no significant difference in glucose uptake between the SU11274-treated and untreated cells. SU11274-treated cells exhibited significantly higher levels of released lactate in comparison to untreated cells, *p < 0.05