Cytotoxic nature of P276-00 is due to phosphorylation of P53 in FaDu cells. (a) Western blot analysis of phosphorylated-P53 in FaDu cells treated with 1 and 3 μM P276-00 for the 24 hours. (b) Dose dependent relative mRNA expression of downstream target of P53 after 24 hours of treatment. Data in histograms represented on log2 scale as mean ± S.E.M. (n = 3). (c-d) Dose dependent treatment of P276-00 (8 different concentrations -range 0.03 to 10 μM) for 24 hours has shown induction of P53 phosphorylation at Ser392 and cleavage of CASP3 in FaDu cells detected by Automated fluorescence imaging (HCS reader) (c) Graphical representation of the data (d) Representative images.