title: Quantitative chemical proteomics reveals new potential drug targets in head and neck cancer.
abstract: Tumors of the head and neck represent a molecularly diverse set of human cancers, but relatively few proteins have actually been shown to drive the disease at the molecular level. To identify new targets for individualized diagnosis or therapeutic intervention, we performed a kinase centric chemical proteomics screen and quantified 146 kinases across 34 head and neck squamous cell carcinoma (HNSCC) cell lines using intensity-based label-free mass spectrometry. Statistical analysis of the profiles revealed significant intercell line differences for 42 kinases (p < 0.05), and loss of function experiments using siRNA in high and low expressing cell lines identified kinases including EGFR, NEK9, LYN, JAK1, WEE1, and EPHA2 involved in cell survival and proliferation. EGFR inhibition by the small molecule inhibitors lapatinib, gefitinib, and erlotinib as well as siRNA led to strong reduction of viability in high but not low expressing lines, confirming EGFR as a drug target in 10-20% of HNSCC cell lines. Similarly, high, but not low EPHA2-expressing cells showed strongly reduced viability concomitant with down-regulation of AKT and ERK signaling following EPHA2 siRNA treatment or EPHA1-Fc ligand exposure, suggesting that EPHA2 is a novel drug target in HNSCC. This notion is underscored by immunohistochemical analyses showing that high EPHA2 expression is detected in a subset of HNSCC tissues and is associated with poor prognosis. Given that the approved pan-SRC family kinase inhibitor dasatinib is also a very potent inhibitor of EPHA2, our findings may lead to new therapeutic options for HNSCC patients. Importantly, the strategy employed in this study is generic and therefore also of more general utility for the identification of novel drug targets and molecular pathway markers in tumors. This may ultimately lead to a more rational approach to individualized cancer diagnosis and therapy.
authors.affiliation: Chair of Proteomics and Bioanalytics, Technische Universität München, Freising, Germany.
authors.forename: Zhixiang
authors.initials: Z
authors.lastname: Wu
authors.forename: Jessica B
authors.initials: JB
authors.lastname: Doondeea
authors.forename: Amin Moghaddas
authors.initials: AM
authors.lastname: Gholami
authors.forename: Melanie C
authors.initials: MC
authors.lastname: Janning
authors.forename: Simone
authors.initials: S
authors.lastname: Lemeer
authors.forename: Karl
authors.initials: K
authors.lastname: Kramer
authors.forename: Suzanne A
authors.initials: SA
authors.lastname: Eccles
authors.forename: Susanne M
authors.initials: SM
authors.lastname: Gollin
authors.forename: Reidar
authors.initials: R
authors.lastname: Grenman
authors.forename: Axel
authors.initials: A
authors.lastname: Walch
authors.forename: Stephan M
authors.initials: SM
authors.lastname: Feller
authors.forename: Bernhard
authors.initials: B
authors.lastname: Kuster
mesh_terms: D002277:Carcinoma / Q000188:drug therapy / Q000201:enzymology*; D018797:Cell Cycle Proteins / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival; D066246:ErbB Receptors / Q000378:metabolism; D055785:Gene Knockdown Techniques; D006801:Humans; D053613:Janus Kinase 1 / Q000378:metabolism; D058990:Molecular Targeted Therapy; D000072379:NIMA-Related Kinases; D009687:Nuclear Proteins / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D040901:Proteomics; D019859:Proto-Oncogene Proteins c-met / Q000378:metabolism; D034622:RNA Interference; D036104:Receptor, EphA2 / Q000235:genetics / Q000378:metabolism*; D053475:Receptor-Interacting Protein Serine-Threonine Kinase 2 / Q000378:metabolism; D046888:Tissue Array Analysis; D014062:Tongue Neoplasms / Q000188:drug therapy / Q000201:enzymology*; D019061:src-Family Kinases / Q000235:genetics / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases; D019859:Proto-Oncogene Proteins c-met; D036104:Receptor, EphA2; C507904:JAK1 protein, human; D053613:Janus Kinase 1; C499349:WEE1 protein, human; D019061:src-Family Kinases; C462119:NEK9 protein, human; D000072379:NIMA-Related Kinases; D017346:Protein Serine-Threonine Kinases; C506253:RIPK2 protein, human; D053475:Receptor-Interacting Protein Serine-Threonine Kinase 2