MDMX regulation of p53 response to ribosomal stress.
Ribosomal stress such as disruption of rRNA biogenesis activates p53 by release of ribosomal proteins from the nucleoli, which bind to MDM2 and inhibit p53 degradation. We found that p53 activation by ribosomal stress requires degradation of MDMX in an MDM2-dependent fashion. Tumor cells overexpressing MDMX are less sensitive to ... actinomycin D-induced growth arrest due to formation of inactive p53-MDMX complexes. Knockdown of MDMX increases sensitivity to actinomycin D, whereas MDMX overexpression abrogates p53 activation and prevents growth arrest. Furthermore, MDMX expression promotes resistance to the chemotherapeutic agent 5-fluorouracil (5-FU), which at low concentrations activates p53 by inducing ribosomal stress without significant DNA damage signaling. Knockdown of MDMX abrogates HCT116 tumor xenograft formation in nude mice. MDMX overexpression does not accelerate tumor growth but increases resistance to 5-FU treatment in vivo. Therefore, MDMX is an important regulator of p53 response to ribosomal stress and RNA-targeting chemotherapy agents.
Mesh Terms:
Animals, Antineoplastic Agents, Cell Line, Tumor, Cell Proliferation, DNA Damage, Dactinomycin, Drug Resistance, Neoplasm, Female, Fluorouracil, Humans, Mice, Mice, Nude, Neoplasms, Nuclear Proteins, Proto-Oncogene Proteins, Proto-Oncogene Proteins c-mdm2, RNA, Ribosomal, Ribosomal Proteins, Ribosomes, Tumor Suppressor Protein p53, Xenograft Model Antitumor Assays
Animals, Antineoplastic Agents, Cell Line, Tumor, Cell Proliferation, DNA Damage, Dactinomycin, Drug Resistance, Neoplasm, Female, Fluorouracil, Humans, Mice, Mice, Nude, Neoplasms, Nuclear Proteins, Proto-Oncogene Proteins, Proto-Oncogene Proteins c-mdm2, RNA, Ribosomal, Ribosomal Proteins, Ribosomes, Tumor Suppressor Protein p53, Xenograft Model Antitumor Assays
EMBO J.
Date: Nov. 29, 2006
PubMed ID: 17110929
View in: Pubmed Google Scholar
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