Protein expression profiling of primary mammary epithelial cells derived from MMTV‐neu mice revealed that HER2/NEU‐driven changes in protein expression are functionally clustered

MMTV‐neu transgenic mice overexpressing NEU in their mammary glands develop tumor after 6 months of age. To find a novel protein biomarker using this mouse model, we identified and characterized the proteins that were differently expressed between primary mammary epithelial cells from 2 months old MMTV‐neu heterozygote mice and wild type (WT) littermates using two‐dimensional digest (ChemDigest™/Trypsin)‐LC‐MS/MS. The differentially expressed proteins were selected and analyzed using DAVID Bioinformatics resource. The proteins involved in anti‐apoptosis, purine metabolism, ribosome and proteasome functions were upregulated, whereas cell adhesion‐related proteins were downregulated in PMECs from MMTV‐neu mice when compared with WT PMECs. The results indicate that several functional units are coregulated by HER2/NEU. We hypothesize that these changes in the cellular proteome may be responsible for early onset of HER2/NEU‐driven tumorigenesis. © 2009 IUBMB IUBMB Life, 62(1):41–50, 2010