Identification and characterization of a cell cycle and apoptosis regulatory protein-1 as a novel mediator of apoptosis signaling by retinoid CD437.
CD437, a novel retinoid, causes cell cycle arrest and apoptosis in a number of cancer cells including human breast carcinoma (HBC) by utilizing an undefined retinoic acid receptor/retinoid X receptor-independent mechanism. To delineate mediators of CD437 signaling, we utilized a random antisense-dependent functional knockout genetic approach. We identified a cDNA that encodes approximately 130-kDa HBC cell perinuclear protein (termed CARP-1). Treatments with CD437 or chemotherapeutic agent adriamycin, as well as serum deprivation of HBC cells, stimulate CARP-1 expression. Reduced levels of CARP-1 result in inhibition of apoptosis by CD437 or adriamycin, whereas increased expression of CARP-1 causes elevated levels of cyclin-dependent kinase inhibitor p21WAF1/CIP1 and apoptosis. CARP-1 interacts with 14-3-3 protein as well as causes reduced expression of cell cycle regulatory genes including c-Myc and cyclin B1. Loss of c-Myc sensitizes cells to apoptosis by CARP-1, whereas expression of c-Myc or 14-3-3 inhibits CARP-1-dependent apoptosis. Thus, apoptosis induction by CARP-1 involves sequestration of 14-3-3 and CARP-1-mediated altered expression of multiple cell cycle regulatory genes. Identification of CARP-1 as a key mediator of signaling by CD437 or adriamycin allows for delineation of pathways that, in turn, may prove beneficial for design and targeting of novel antitumor agents.
Pubmed ID: 12816952 RIS Download
3' Untranslated Regions | 5' Untranslated Regions | Antineoplastic Agents | Apoptosis | Apoptosis Regulatory Proteins | Blotting, Western | Cell Cycle Proteins | Cell Line | Cell Nucleus | Cloning, Molecular | Coloring Agents | DNA, Complementary | Doxorubicin | Electrophoresis, Polyacrylamide Gel | Flow Cytometry | Gene Expression Regulation | Humans | Models, Biological | Neoplasms, Glandular and Epithelial | Oligonucleotides | Oligonucleotides, Antisense | Open Reading Frames | Plasmids | Precipitin Tests | Protein Binding | Proto-Oncogene Proteins c-myc | Retinoids | Retroviridae | Tetrazolium Salts | Thiazoles | Time Factors | Tumor Cells, Cultured