Dkk3 regulates cell death. (A) HEK293 cells were transiently transfected with LacZ, Dkk3, or BclxL and exposed to H2O2 for 24 hr. Viability was measured by XTT assay and was normalized to 0 mM H2O2. Dkk3 expression significantly increased viability in the presence of H2O2 compared with LacZ control. There was no difference between Dkk3 and BclXL. ** = p < 0.001, comparison between Dkk3 and LacZ. The comparison between BclXL and LacZ was also significant at p < 0.001 at each concentration of H2O2. (B) Dkk3 significantly protected HEK293 cells against apoptosis induced by staurosporine. HEK293 cells expressing Dkk3 or Vector control were exposed to 1 μM staurosporine (STS) or the DMSO vehicle control for 16 hrs. Caspase activity was measured and relative fluorescent intensity (RFI) units were normalized to micrograms of protein. *** = p < 0.001, comparison between Dkk3 cells and Vector cells treated with STS. (C) Dkk3 did not protect COS7 cells exposed to staurosporine. Caspase activity (RFI/microgram of protein) was compared with cells transfected with the pcDNA3 empty vector. Mean ± standard deviation is shown.
Nakamura et al. BMC Cell Biology 2007 8:52 doi:10.1186/1471-2121-8-52