Synergistic antitumor activity of epidermal growth factor receptor tyrosine kinase inhibitor gefitinib and IFN-alpha in head and neck cancer cells in vitro and in vivo.
OBJECTIVE
Epidermal growth factor receptor (EGFR) overexpression has been implicated in the development of head and neck squamous cell carcinomas (HNSCC) and represents a potential therapeutic target for this disease. We have reported previously that growth inhibitory concentrations of IFN-alpha enhance the expression and activity of EGFR and that this effect could represent an escape mechanism to the growth inhibition and apoptotic cell death induced by IFN-alpha. In this study, we investigate whether the combination of IFN-alpha and gefitinib (Iressa, AstraZeneca Pharmaceuticals, Macclesfield, United Kingdom), a selective EGFR tyrosine kinase inhibitor, might have a cooperative antitumor effect on HNSCC-derived cell lines.


METHODS
The interaction of IFN-alpha and gefitinib was evaluated in vitro on HNSCC-derived cell lines by median drug effect analysis calculating a combination index with CalcuSyn software and in vivo by using HNSCC xenografts in nude mice. The mechanism of gefitinib and IFN-alpha interactions was also studied by analysis of cell cycle kinetics, apoptosis assays, and Western blotting of EGFR signal transduction components.


RESULTS
Simultaneous exposure to gefitinib and IFN-alpha produced synergistic antiproliferative and proapoptotic effects compared with single drug treatment. Furthermore, daily treatment of gefitinib (50 mg/kg p.o.) in combination with an IFN-alpha regimen (50,000 units s.c. three times weekly) induced tumor growth delay and increased survival rate on established HNSCC xenografts in nude mice. Moreover, the concomitant treatment with gefitinib suppressed the stimulation of extracellular signal-regulated kinase phosphorylation/activity induced by IFN-alpha both in vitro and in vivo.


CONCLUSIONS
The observed cooperative antitumor effects could be, at least in part, explained by the inhibition exerted by gefitinib of an IFN-alpha-induced EGF-dependent survival pathway, which involves extracellular signal-regulated kinase activation. These results provide a rationale for the clinical evaluation of gefitinib in combination with IFN-alpha in HNSCC.
Bruzzese
Francesca
F
Experimental Pharmacology Unit, Department of Experimental Oncology, National Cancer Institute G. Pascale, via M. Semmola, 80131 Naples, Italy.
Di Gennaro
Elena
E
Avallone
Antonio
A
Pepe
Stefano
S
Arra
Claudio
C
Caraglia
Michele
M
Tagliaferri
Pierosandro
P
Budillon
Alfredo
A
D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D004357:Drug Synergism; D066246:ErbB Receptors / Q000037:antagonists & inhibitors* / Q000378:metabolism; D005260:Female; D000077156:Gefitinib; D006258:Head and Neck Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D066298:In Vitro Techniques; D016898:Interferon-alpha / Q000008:administration & dosage; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D011799:Quinazolines / Q000008:administration & dosage; D015398:Signal Transduction / Q000187:drug effects; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays
D016898:Interferon-alpha; D011799:Quinazolines; D066246:ErbB Receptors; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D000077156:Gefitinib