9AA activates phosphorylation of p53 at Ser15. CEM and ACH2 cells were treated with drug 9AA, P44 peptide or DMSO as mock control, respectively. Cells were harvested 24 hrs after treatment. Cells were then lysed and subjected to western blot for p53, p53ser15 and p21/waf1 (anti-p53, anti-p53 ser15 from Cell Signaling, anti-p21/waf1 from Santa Cruz Biotechnology). (A) CEM cells, uninfected cells. (B) ACH2 cells, HIV-1 infected cells. (C) ACH2 cells were treated with 9AA at a concentration of 2.5 uM. Cells were collected at different time points and then subjected to western blot for detection of the phosphorylation of p53ser 15. Actin was used as a loading control.