The effect of 2'-2' difluorodeoxycytidine (dFdC, gemcitabine) on radiation-induced cell lethality in two human head and neck squamous carcinoma cell lines differing in intrinsic radiosensitivity
| Autor: | Marc De Bast, Pierre Scalliet, Vincent Grégoire, M. Octaveprignot, Jean-Claude Rosier, B M De Coster, M Bruniaux, Marc Beauduin |
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| Rok vydání: | 1999 |
| Předmět: |
Pathology
medicine.medical_specialty Radiation-Sensitizing Agents Cell Deoxycytidine Radiation Tolerance Radioresistance medicine Tumor Cells Cultured Humans Radiology Nuclear Medicine and imaging Radiosensitivity Radiological and Ultrasound Technology Cell Death business.industry Combined Modality Therapy Gemcitabine Squamous carcinoma medicine.anatomical_structure Epidermoid carcinoma Cell culture Head and Neck Neoplasms Toxicity Cancer research Carcinoma Squamous Cell business medicine.drug |
| Zdroj: | International journal of radiation biology. 75(2) |
| ISSN: | 0955-3002 |
| Popis: | The present study investigated in vitro radio-enhancement by gemcitabine (dFdC) in two head and neck squamous cell carcinomas with different intrinsic cellular radiosensitivity.Radiosensitive (SCC61, SF2=0.16) and radioresistant (SQD9, SF2=0.49) human head and neck squamous cell carcinomas were used. Confluent cells were incubated with dFdC and irradiated in drug-free medium with a single dose of 250 kV X-rays (0-12Gy). Cell survival curves were corrected for the toxicity of the drug alone.In both cell lines, radio-enhancement was observed with 5 microM dFdC incubated for 3 h prior to irradiation. Dose modification factors (DMF) at a surviving fraction level of 0.5 reached 1.3 (95% CI 1.1-1.6) and 1.5 (95% CI 1.4-1.5) for SQD9 and SCC61 cells, respectively. Radio-enhancement was associated with a modest increase in the alpha term of the linear-quadratic model. In SQD9 cells, radio-enhancement increased with dFdC incubation time. At 24h, DMF reached a value of 1.5 (95% CI 0.9-3.2). In SCC61 cells at 24h, DMF reached a value of 1.1 (95% CI 0.9-1.2). In both cell lines, radio-enhancement increased with dFdC concentration up to 5-10 microM from which values it levelled off up to 100 microM.The data indicated that dFdC induced a modest radio-enhancement in both cell lines. For a short incubation time, dFdC did not radio-enhance preferentially the more radio-resistant cells, whereas the opposite was observed for a longer time. In both cell lines, radio-enhancement was saturated above a dFdC concentration of 5-10 microM. |
| Databáze: | OpenAIRE |
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