Quantitative proteomics analysis reveals molecular networks regulated by epidermal growth factor receptor level in head and neck cancer.
Epidermal growth factor receptor (EGFR) is overexpressed in up to 90% of head and neck cancer (HNC), where increased expression levels of EGFR correlate with poor prognosis. To date, EGFR expression levels have not predicted the clinical response to the EGFR-targeting therapies. Elucidation of the molecular mechanisms underlying anti-EGFR-induced antitumor effects may shed some light on the mechanisms of HNC resistance to EGFR-targeting therapeutics and provide novel targets for improving the treatment of HNC. Here, we conducted a quantitative proteomics analysis to determine the molecular networks regulated by EGFR levels in HNC by specifically knocking-down EGFR and employing stable isotope labeling with amino acids in cell culture (SILAC). Following data normalization to minimize systematic errors and Western blotting validation, 12 proteins (e.g., p21, stratifin, and maspin) and 24 proteins (e.g., cdc2 and MTA2) were found to be significantly upregulated or downregulated by EGFR knockdown, respectively. Bioinformatic analysis revealed that these proteins were mainly involved in long-chain fatty acid biosynthesis and beta-oxidation, cholesterol biosynthesis, cell proliferation, DNA replication, and apoptosis. Cell cycle analysis confirmed that G(2)/M phase progression was significantly inhibited by EGFR knockdown, a hypothesis generated from network modeling. Further investigation of these molecular networks may not only enhance our understanding of the antitumor mechanisms of EGFR targeting but also improve patient selection and provide novel targets for better therapeutics.
Yang
Wei
W
Urological Diseases Research Center, Department of Urology, Children's Hospital Boston, Boston, Massachusetts 02115, USA.
Cai
Quan
Q
Lui
Vivian W Y
VW
Everley
Patrick A
PA
Kim
Jayoung
J
Bhola
Neil
N
Quesnelle
Kelly M
KM
Zetter
Bruce R
BR
Steen
Hanno
H
Freeman
Michael R
MR
Grandis
Jennifer R
JR
D015153:Blotting, Western; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism; D045744:Cell Line, Tumor; D002784:Cholesterol / Q000378:metabolism; D066246:ErbB Receptors / Q000235:genetics* / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism; D055785:Gene Knockdown Techniques; D006258:Head and Neck Neoplasms / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D007553:Isotope Labeling; D053858:Metabolic Networks and Pathways; D020543:Proteome / Q000378:metabolism; D040901:Proteomics / Q000379:methods*; D034741:RNA, Small Interfering / Q000235:genetics; D015203:Reproducibility of Results; D015398:Signal Transduction
D018797:Cell Cycle Proteins; D005227:Fatty Acids; D020543:Proteome; D034741:RNA, Small Interfering; D002784:Cholesterol; D066246:ErbB Receptors