Inhibition of Breast Cancer Growth by IGFBP-3

摘要

The proposal of my grant is to investigate the biological significance and mechanism of insulin-like growth factor binding protein-3 (IGFBP-3) as well as identification and characterization of the IGFBP-3 receptor in human breast cancer cells. As a second year task, I have successfully screened the IGFBP-3 interacting proteins including putative IGFBP-3 receptor in human breast cancer cells by employing the yeast two-hybrid system. Two cDNA clones matched sequences in the GenBank database: (1) Eps8 - epidermal growth factor receptor kinase substrate, and (2) GRP78/BiP - glucose regulated stress protein, or human immunoglobulin heavy chain binding protein. The third cDNA, designated clone 4-33, was not identified in the database and represents a novel gene / protein. I have thus far concentrated my efforts on this novel cDNA clone: (1) synthesis of recombinant human 4-33 protein by use of a Glutathione S-Transferase fusion and (2) generation of polyclonal 4-33 antibodies.