Bnip3L is induced by p53 under hypoxia, and its knockdown promotes tumor growth.
p53-dependent apoptosis is a major determinant of its tumor suppressor activity and can be triggered by hypoxia. No p53 target is known to be induced by p53 or to mediate p53-dependent apoptosis during hypoxia. We report that p53 can directly upregulate expression of Bnip3L, a cell death inducer. During hypoxia, Bnip3L is highly induced in wild-type p53-expressing cells, in part due to increased recruitment of p53 and CBP to Bnip3L. Apoptosis is reduced in hypoxia-exposed cells with functional p53 following Bnip3L knockdown. In vivo, Bnip3L knockdown promotes tumorigenicity of wild-type versus mutant p53-expressing tumors. Thus, Bnip3L, capable of attenuating tumorigenicity, mediates p53-dependent apoptosis under hypoxia, which provides a novel understanding of p53 in tumor suppression.
Pubmed ID: 15607964 RIS Download
Animals | Apoptosis | Blotting, Western | CREB-Binding Protein | Caspase 3 | Caspases | Cell Hypoxia | Cell Line, Tumor | Cell Proliferation | Chromatin Immunoprecipitation | Cisplatin | Doxycycline | Fluorouracil | Gene Expression Regulation, Neoplastic | Genes, Reporter | Glucose Transporter Type 1 | Humans | Immunohistochemistry | In Situ Hybridization | Membrane Proteins | Mice | Mice, Nude | Monosaccharide Transport Proteins | Neoplasms | Nuclear Proteins | Oligonucleotide Array Sequence Analysis | Protein Binding | Proto-Oncogene Proteins | RNA Interference | RNA, Small Interfering | Repressor Proteins | Trans-Activators | Transfection | Tumor Suppressor Protein p53 | Tumor Suppressor Proteins | Xenograft Model Antitumor Assays