Selective inhibition of the epidermal growth factor receptor tyrosine kinase by BIBX1382BS and the improvement of growth delay, but not local control, after fractionated irradiation in human FaDu squamous cell carcinoma in the nude mouse
| Autor: | Cordula Petersen, D. Zips, Michael H. Baumann, Wolfgang Eicheler, J. Ahrens, Mechthild Krause, Kerstin Brüchner, Frank Hilberg, Annegret Dörfler |
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| Rok vydání: | 2003 |
| Předmět: |
Male
Receptor Status Cell Survival Transplantation Heterologous Mice Nude Apoptosis Mice Nude mouse Animals Doubling time Radiology Nuclear Medicine and imaging Epidermal growth factor receptor Enzyme Inhibitors Organic Chemicals Radiological and Ultrasound Technology biology Cell growth Cell cycle biology.organism_classification ErbB Receptors Carcinoma Squamous Cell Neoplastic Stem Cells Cancer research biology.protein Female Dose Fractionation Radiation A431 cells Neoplasm Transplantation |
| Zdroj: | International Journal of Radiation Biology. 79:547-559 |
| ISSN: | 1362-3095 0955-3002 |
| DOI: | 10.1080/0955300031000112839 |
| Popis: | To investigate the effect of BIBX1382BS, an inhibitor of the epidermal growth factor receptor tyrosine kinase, on proliferation and clonogenic cell survival of FaDu human squamous cell carcinoma in vitro, and on tumour growth and local tumour control after fractionated irradiation over 6 weeks in nude mice. FaDu human squamous cell carcinoma is epidermal growth factor receptor positive and significant repopulation during fractionated irradiation was demonstrated in previous experiments.Receptor status, receptor phosphorylation, cell cycle distribution, cell proliferation and clonogenic cell survival after irradiation were assayed with and without BIBX1382BS (5 microM) in vitro. Tumour volume doubling time, BrdUrd and Ki67 labelling indices and apoptosis were investigated in unirradiated tumours growing in NMRI nude mice treated daily with BIBX1382BS (50 mg kg(-1) body weight orally) or carrier. Tumour growth delay and dose-response curves for local tumour control were determined after irradiation with 30 fractions within 6 weeks.BIBX1382BS blocked radiation-induced phosphorylation of the epidermal growth factor receptor and reduced the doubling time of FaDu cells growing in vitro by a factor of 4.9 (p=0.008). Radiosensitivity in vitro remained unchanged after incubation with BIBX1382BS for 3 days and decreased moderately after 6 days (p=0.001). BIBX1382BS significantly reduced the volume doubling time of established FaDu tumours in nude mice by factors of 2.6 when given over 15 days (p0.001) and 3.7 when applied over 6 weeks (p0.001). When given simultaneously to fractionated irradiation, growth delay was significantly prolonged by an average of 33 days (p=0.003). Local tumour control was not improved by BIBX1382BS. The radiation doses necessary to control 50% of the tumours locally were 63.6 Gy (95% confidence interval 55; 73) for irradiation alone and 67.8 Gy (60; 77) for the combined treatment (p=0.5).Despite clear antiproliferative activity in rapidly repopulating FaDu human squamous cell carcinoma and significantly increased tumour growth delay when combined with fractionated irradiation, local tumour control was not improved by BIBX1382BS. The results do not disprove that epidermal growth factor receptor inhibition might enhance the results of radiotherapy. However, the results imply that further preclinical investigations using relevant treatment schedules and appropriate endpoints are necessary to explore the mechanisms of action and efficacy of such combinations. |
| Databáze: | OpenAIRE |
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