Crizotinib Fails to Enhance the Effect of Radiation in Head and Neck Squamous Cell Carcinoma Xenografts.
OBJECTIVE
Mesenchymal-epithelial transition factor (MET), a receptor tyrosine kinase, is expressed in head and neck squamous cell carcinomas (HNSCC) and is involved in tumor progression and associated with poor prognosis. MET can be inhibited by crizotinib, a potent ATP-competitive kinase inhibitor. We examined the effects of combining crizotinib and radiation in a pre-clinical HNSCC model.


METHODS
Nine HNSCC cell lines were screened for MET expression, copy-number amplification and mutational status. The in vitro effects of crizotinib and radiation were assessed with clonogenic survival assays. MET signaling proteins were assessed with western blot and receptor tyrosine kinase array. Tumor growth-delay experiments with UT-SCC-14 and UT-SCC-15 oral tongue xenografts were used to assess in vivo tumor radiosensitivity.


RESULTS
All nine HNSCC cell lines showed a varying degree of MET protein and RNA expression. Increased MET copy number was not present. MET was expressed after irradiation both in vitro and in vivo. Crizotinib alone inhibited phosphorylation of MET and inhibited cell growth in vitro but did not inhibit phosphorylation of downstream signaling proteins: MAPK, AKT or c-SRC. When combined with radiation in vitro, crizotinib demonstrated radiation enhancement in only one cell line. Crizotinib did not enhance the effect of radiation in either UT-SCC-14 or UT-SCC-15 tumors grown as xenografts.


CONCLUSIONS
MET is overexpressed in HNSCC cell lines, however, crizotinib failed to enhance the radiation response and failed to inhibit MET downstream signaling proteins in this HNSCC model.
Department of Human Oncology, Universtiy of Wisconsin, Carbone Cancer Center, Madison, WI, U.S.A.
Andrew M
AM
Baschnagel
Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI, U.S.A.
Sandra
S
Galoforo
Beaumont BioBank, William Beaumont Hospital, Royal Oak, MI, U.S.A.
Bryan J
BJ
Thibodeau
Beaumont BioBank, William Beaumont Hospital, Royal Oak, MI, U.S.A.
Samreen
S
Ahmed
Beaumont BioBank, William Beaumont Hospital, Royal Oak, MI, U.S.A.
Sonali
S
Nirmal
Beaumont BioBank, William Beaumont Hospital, Royal Oak, MI, U.S.A. Department of Otolaryngology, William Beaumont Hospital, Royal Oak, MI, U.S.A.
Jan
J
Akervall
Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI, U.S.A. Beaumont BioBank, William Beaumont Hospital, Royal Oak, MI, U.S.A. George.Wilson@beaumont.edu.
George D
GD
Wilson
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D015153:Blotting, Western; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy*; D049109:Cell Proliferation / Q000187:drug effects / Q000528:radiation effects; D000077547:Crizotinib; D056915:DNA Copy Number Variations; D005260:Female; D006258:Head and Neck Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D007124:Immunoenzyme Techniques; D051379:Mice; D008819:Mice, Nude; D010766:Phosphorylation / Q000187:drug effects / Q000528:radiation effects; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D019859:Proto-Oncogene Proteins c-met / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D011720:Pyrazoles / Q000494:pharmacology*; D011725:Pyridines / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics; D011836:Radiation Tolerance / Q000187:drug effects*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects / Q000528:radiation effects; D014407:Tumor Cells, Cultured; D014965:X-Rays; D023041:Xenograft Model Antitumor Assays
D047428:Protein Kinase Inhibitors; D011720:Pyrazoles; D011725:Pyridines; D012333:RNA, Messenger; D000077547:Crizotinib; D019859:Proto-Oncogene Proteins c-met
HGF; MET; c-MET; crizotinib; head and neck cancer; radiation