Fig. 8. p53-dependent radiosensitization but p53-independent cell kill by STP.
A, proliferation of E1A/ras-transformed p53-deficient
cells was assessed 24 h after treatment with STP (20
nM) and IR (5 Gy) or both in combination. B,
proliferation of the transformed p53-deficient cells after treatment
with increasing doses of STP (0, 20, and 300 nM).
C, caspase-3-like activity was determined 6 h after
treatment in cytosolic extracts from p53-deficient cells using
Ac-DEVD-pNA as a colorimetric caspase-3 substrate (CTL)
6 h after treatment with STP. D, formation of
active caspase-3 was determined after STP treatment (300
nM) using an antibody recognizing the cleaved caspase-3