Huntingtin interacting protein 1 is a novel brain tumor marker that associates with epidermal growth factor receptor.
Huntingtin interacting protein 1 (HIP1) is a multidomain oncoprotein whose expression correlates with increased epidermal growth factor receptor (EGFR) levels in certain tumors. For example, HIP1-transformed fibroblasts and HIP1-positive breast cancers have elevated EGFR protein levels. The combined association of HIP1 with huntingtin, the protein that is mutated in Huntington's disease, and the known overexpression of EGFR in glial brain tumors prompted us to explore HIP1 expression in a group of patients with different types of brain cancer. We report here that HIP1 is overexpressed with high frequency in brain cancers and that this overexpression correlates with EGFR and platelet-derived growth factor beta receptor expression. Furthermore, serum samples from patients with brain cancer contained anti-HIP1 antibodies more frequently than age-matched brain cancer-free controls. Finally, we report that HIP1 physically associates with EGFR and that this association is independent of the lipid, clathrin, and actin interacting domains of HIP1. These findings suggest that HIP1 may up-regulate or maintain EGFR overexpression in primary brain tumors by directly interacting with the receptor. This novel HIP1-EGFR interaction may work with or independent of HIP1 modulation of EGFR degradation via clathrin-mediated membrane trafficking pathways. Further investigation of HIP1 function in brain cancer biology and validation of its use as a prognostic or predictive brain tumor marker are now warranted.
Bradley
Sarah V
SV
Department of Internal Medicine, University of Michigan Medical School, 1500 East Medical Center Drive, Ann Arbor, MI 48109, USA.
Holland
Eric C
EC
Liu
Grace Y
GY
Thomas
Dafydd
D
Hyun
Teresa S
TS
Ross
Theodora S
TS
D000199:Actins / Q000378:metabolism; D000912:Antibodies, Neoplasm / Q000097:blood; D014408:Biomarkers, Tumor / Q000096:biosynthesis / Q000378:metabolism; D001921:Brain / Q000378:metabolism; D001932:Brain Neoplasms / Q000276:immunology / Q000378:metabolism*; D002966:Clathrin / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism*; D066246:ErbB Receptors / Q000096:biosynthesis / Q000378:metabolism*; D006801:Humans; D047468:Immunoprecipitation; D050356:Lipid Metabolism; D011485:Protein Binding
D000199:Actins; D000912:Antibodies, Neoplasm; D014408:Biomarkers, Tumor; D002966:Clathrin; D004268:DNA-Binding Proteins; C073368:HIP1 protein, human; D066246:ErbB Receptors