Figure 7. SGI-1776 displays anti-tumor activity in combination with a PI3K inhibitor in 3D melanoma models.

(A) Melanoma cells were treated with increasing doses of SGI-1776 or AZD6482 for 72 h and were assessed using the alamarBlue assay. The mean % of proliferation compared to the DMSO control is shown (from three experiments). Blue indicates no inhibition, red indicates high inhibition. Synergy was calculated for combination experiments using the Bliss formula. The Bliss number gives the difference between predicted and observed inhibition values (excess over Bliss); a positive value indicates synergy, a negative value indicates antagonism and values near zero indicate an overlap of predicted and observed combination effects. (B) 1205Lu spheroid lysates were interrogated for effectors of AKT and STAT3 signaling, as well as cleaved PARP by western blots. Vinculin was used as a loading control. (C) Collagen-embedded melanoma spheroids were treated for 72 h with SGI-1776 [5 μM] or AZD6482 [10 μM] as single agents or in combination before staining for live (green) and dead (red) cells. Experiments were conducted in triplicate and representative images are shown. Scale bar represents 150 microns.