Figure 2.

Greater PTS activity and increased sensitivity to AP in mutant BRAF^V600E human melanoma cells compared to wild type (WT) BRAF^WT cells. (A) BRAF^V600E human melanoma cells (WM983B, WM3734, 1205Lu, WM989, and WM88) and BRAF^WT human melanoma cells (WM3451, WM3743, and WM3211) were cultured with and without 1 mM DFMO for 40 h and then pulsed with 0.5 µM ³H-spermidine for 60 min at 37 °C. Cell lysates were assayed for CPM ³H-spermidine per mg protein by scintillation counting. The mean PTS activity ± SD for BRAF^WT melanoma cells is compared with that of BRAF^V600E melanoma cells under conditions where cells were cultured without added DFMO or with 1 mM DFMO. (B) BRAF^V600E human melanoma cells (WM983B, WM3734, 1205Lu, WM989, and WM88) and BRAF^WT human melanoma cells (WM3451, WM3743, and WM3211) were treated with increasing doses of AP with or without 1 mM DFMO, using 5–6 samples per dose of AP. After 72 h of culture, cell survival was determined via EZQuant Cell Quantifying assay (Alstem, Richmond, CA, USA). AP IC50 values were calculated by GraphPad Prism 6. The mean AP IC50 values ± SD for BRAF^WT melanoma cells is compared with that of BRAF^V600E melanoma cells under conditions where cells were cultured without added DFMO or with 1 mM DFMO; # p ≤ 0.05; * p < 0.01.