PURPOSE: Human Raji cells treated with fludarabine nucleoside (2-FaraA, 3 μM) undergo apoptosis with accumulation of p53 in the nuclei as multiple phosphorylated isoforms and C-terminal truncated derivatives. Changes induced by 2-FaraA in the levels of p53, p63 and p73 in the nuclear, cytosolic and mitochondrial fractions have been determined in four human B-lymphoid cell lines that are TP53-functional (Raji and IM9) and TP53-mutated (MEC1 and U266). EXPERIMENTAL DESIGN: The B-lymphoid cell lines were treated with 2-FaraA (3 μM, 24 h, 48 h) and viability determined. Protein extracts of subcellular fractions from 2-FaraA-treated cells were analysed by 1D and 2D electrophoresis; multiple phosphorylated isoforms and truncated derivatives were identified by Western blots for p53, p63 and p73. RESULTS: p53 and p63 were present in all three fractions, while p73 was only detected in nuclei. After treatment with 2-FaraA, nuclear p53, p63 and p73 accumulated as multiple phosphorylated isoforms and truncated derivatives. The association of p63 with mitochondria in human cells is novel. CONCLUSIONS AND CLINICAL RELEVANCE: Comprehensive information on the subcellular distributions and responses of p53, p63 and p73 to 2-FaraA provides additional insight into mechanisms for induction of apoptosis in the treatment of B-lymphoproliferative disorders with fludarabine.
Bibliographical note1862-8354 Almazi, Juhura G Mactier, Swetlana Best, O Giles Crossett, Ben Mulligan, Stephen P Christopherson, Richard I Journal Article Research Support, Non-U.S. Gov't Germany Proteomics Clin Appl. 2012 Jun;6(5-6):279-90. doi: 10.1002/prca.201200003.
- Antineoplastic Agents/*pharmacology Apoptosis Cell Line, Tumor Cell Nucleus/*metabolism Cytosol/*metabolism DNA-Binding Proteins/*metabolism Humans Membrane Proteins/*metabolism Nuclear Proteins/*metabolism Precursor Cell Lymphoblastic Leukemia-Lymphoma Tumor Protein p73 Tumor Suppressor Protein p53/*metabolism Tumor Suppressor Proteins/*metabolism Vidarabine/*analogs & derivatives/pharmacology