1. Identification of a novel insulin-like growth factor binding protein gene homologue with tumor suppressor like properties.
- Author
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Cai Z, Chen HT, Boyle B, Rupp F, Funk WD, and Dedera DA
- Subjects
- Amino Acid Sequence, Animals, Base Sequence, COS Cells, Chlorocebus aethiops, Cloning, Molecular, HeLa Cells, Humans, Insulin-Like Growth Factor Binding Proteins classification, Insulin-Like Growth Factor Binding Proteins metabolism, Molecular Sequence Data, Phylogeny, Tumor Suppressor Proteins metabolism, Insulin-Like Growth Factor Binding Proteins genetics, Insulin-Like Growth Factor Binding Proteins physiology, Tumor Suppressor Proteins genetics, Tumor Suppressor Proteins physiology
- Abstract
Here we report the identification of a new insulin-like growth factor binding protein homologue, provisionally designated insulin-like growth factor binding related protein-4 (IGFBP-rP4). IGFBP-rP4 was found to be most closely related to IGFBP-7 with 52% amino acid homology and 43% amino acid identity, and shares a similar domain structure. Semi-quantitative RT-PCR expression analysis demonstrated a pattern of downregulation of this gene in multiple tumor samples including lung and colon cancer, compared to matched adjacent normal tissue. Western blotting revealed a protein of approximately 38kDa expressed in both the cell pellet and secreted into the supernatant of transiently transfected Cos-7 cells. Cos-7 supernatants containing IGFBP-RP4 protein were observed to suppress the growth of HeLa cells in culture compared to vector controls. IGFBP-RP4 directly transiently transfected into HeLa cells also further confirmed the growth suppressive properties of this protein. Together these data suggest that IGFBP-RP4 may be a novel putative tumor suppressor protein.
- Published
- 2005
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