A, western blot assay for the expression of BCR-ABL, MDM2, p53 and XIAP in six cultured ALL cell lines. The p53 status of these lines (EU-1, UOC-B1 and Sup-B15: wt-p53; EU-6: mutant-p53; EU-5 and EU-9: p53-null) was previously characterized [28]. B, changes of the expression levels of MDM2 and XIAP by nilotinib treatment. Representative cell lines, as indicated, were treated (T) with 2 µM nilotinib for 24 h. Untreated cells served as a control (C). The expression of proteins was detected by western blot, as indicated. C and D, western blot assays showed the dose-response and time-course of MDM2 and XIAP inhibition by nilotinib, in both BCR-ABL positive (SUP-B15) and negative (EU-1) ALL cell lines.