Figure 6

Activation of DNA-PKcs in MST-312 treated cells and cell survival in brain tumours cells following dual inhibition. (A) DNA-PKcs activation in MST-312 treated cells determined by western blot analysis following 1.0 μM MST-312 and/or 10 μM NU7026 treatments. Increase in the level of phospho-DNA-PKcs was seen in MO59K and KNS60 cells. On the contrary, minimal changes in the level phospho-DNA-PKcs were observed in ONS76 cells. Representative images from two independent experiments are shown (B) Cell survival determined in cells pre-treated with or without low dose MST-312 (0.5 μM) for 6 weeks following which cells were re-plated and treated with MST-312 (1.0 μM) and NU7026 DNA-PKcs inhibition (10.0 μM) for further 48 hours. Combined inhibition of telomerase and DNA-PKcs by MST-312 and NU7026 had the significant reduction in percentage of viable cells for both cells that were pre-treated with a low concentration (0.5 μM) of MST-312 for 6 weeks (6WK) and cells that were not pre-treated. Data represent mean ± SE from 3 independent experiments. *P-value <0.05 when comparing dual inhibited cells to telomerase- inhibited cells for 48 hours. Red star P-value <0.05 when comparing dual inhibited treated cells to telomerase- inhibited cells in pre-MST-312 treated cells.