title: Regulation of heparin-binding EGF-like growth factor by miR-212 and acquired cetuximab-resistance in head and neck squamous cell carcinoma.
abstract: BACKGROUND
  We hypothesized that chronic inhibition of epidermal growth factor receptor (EGFR) by cetuximab, a monoclonal anti-EGFR antibody, induces up-regulation of its ligands resulting in resistance and that microRNAs (miRs) play an important role in the ligand regulation in head and neck squamous cell carcinoma (HNSCC).
  
  
  RESULTS
  Genome-wide changes in gene and miR expression were determined in cetuximab-sensitive cell line, SCC1, and its resistant derivative 1Cc8 using DNA microarrays and RT-PCR. The effects of differentially expressed EGFR ligands and miRs were examined by MTS, colony formation, ELISA, and western blot assays. Heparin-binding EGF-like growth factor (HB-EGF) and its regulator, miR-212, were differentially expressed with statistical significance when SCC1 and 1Cc8 were compared for gene and miR expression. Stimulation with HB-EGF induced cetuximab resistance in sensitive cell lines. Inhibition of HB-EGF and the addition of miR-212 mimic induced cetuximab sensitivity in resistant cell lines. MicroRNA-212 and HB-EGF expression were inversely correlated in an additional 33 HNSCC and keratinocyte cell lines. Six tumors and 46 plasma samples from HNSCC patients were examined for HB-EGF levels. HB-EGF plasma levels were lower in newly diagnosed HNSCC patients when compared to patients with recurrent disease.
  
  
  CONCLUSIONS
  Increased expression of HB-EGF due to down-regulation of miR-212 is a possible mechanism of cetuximab resistance. The combination of EGFR ligand inhibitors or miR modulators with cetuximab may improve the clinical outcome of cetuximab therapy in HNSCC.
authors.affiliation: Division of Hematology/Oncology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Hatakeyama
authors.forename: Haixia
authors.initials: H
authors.lastname: Cheng
authors.forename: Pamela
authors.initials: P
authors.lastname: Wirth
authors.forename: Ashley
authors.initials: A
authors.lastname: Counsell
authors.forename: Samuel R
authors.initials: SR
authors.lastname: Marcrom
authors.forename: Carey Burton
authors.initials: CB
authors.lastname: Wood
authors.forename: Paula R
authors.initials: PR
authors.lastname: Pohlmann
authors.forename: Jill
authors.initials: J
authors.lastname: Gilbert
authors.forename: Barbara
authors.initials: B
authors.lastname: Murphy
authors.forename: Wendell G
authors.initials: WG
authors.lastname: Yarbrough
authors.forename: Deric L
authors.initials: DL
authors.lastname: Wheeler
authors.forename: Paul M
authors.initials: PM
authors.lastname: Harari
authors.forename: Yan
authors.initials: Y
authors.lastname: Guo
authors.forename: Yu
authors.initials: Y
authors.lastname: Shyr
authors.forename: Robbert J
authors.initials: RJ
authors.lastname: Slebos
authors.forename: Christine H
authors.initials: CH
authors.lastname: Chung
mesh_terms: D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D061067:Antibodies, Monoclonal, Humanized; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D000068818:Cetuximab; D015536:Down-Regulation; D019008:Drug Resistance, Neoplasm; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006258:Head and Neck Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism*; D066257:Heparin-binding EGF-like Growth Factor; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; C587883:HBEGF protein, human; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; C551411:MIRN212 microRNA, human; D035683:MicroRNAs; D000068818:Cetuximab