Development of transient radioresistance during fractionated irradiation in vitro.

Autor: van den Berg J; Amsterdam UMC location VUmc, Department of Radiation Oncology, Cancer Center Amsterdam, The Netherlands., Castricum KCM; Amsterdam UMC location VUmc, Department of Radiation Oncology, Cancer Center Amsterdam, The Netherlands., Meel MH; Princess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands., Goedegebuure RSA; Amsterdam UMC location VUmc, Department of Medical Oncology, Cancer Center Amsterdam, The Netherlands., Lagerwaard FJ; Amsterdam UMC location VUmc, Department of Radiation Oncology, Cancer Center Amsterdam, The Netherlands., Slotman BJ; Amsterdam UMC location VUmc, Department of Radiation Oncology, Cancer Center Amsterdam, The Netherlands., Hulleman E; Princess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands., Thijssen VLJL; Amsterdam UMC location VUmc, Department of Radiation Oncology, Cancer Center Amsterdam, The Netherlands. Electronic address: v.thijssen@amsterdamumc.nl.
Jazyk: angličtina
Zdroj: Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology [Radiother Oncol] 2020 Jul; Vol. 148, pp. 107-114. Date of Electronic Publication: 2020 Apr 17.
DOI: 10.1016/j.radonc.2020.04.014
Abstrakt: Background and Purpose: Effective combination treatments with fractionated radiotherapy rely on a proper understanding of the dynamic responses that occur during treatment. We explored the effect of clinical fractionated radiotherapy on the development and timing of radioresistance in tumor cells.
Methods and Materials: Different colon (HT29/HCT116/COLO320/SW480/RKO) and high-grade astrocytoma (D384/U-251MG) cancer cell lines were treated for 6 weeks with daily fractions of 2 Gy, 5 days per week. Clonogenic survival was determined throughout the treatment period. In addition, the radiosensitivity of irradiated and non-irradiated was compared. Finally, the effect of different dose fractions on the development of radioresistance was determined.
Results: All cell lines developed radioresistance within 2-3 weeks during fractionated radiotherapy. This was characterized by the occurrence of a steady state phase of clonogenic survival. In U-251MG cells this was accompanied by increased cell senescence and stemness. After recovering from six weeks of treatment, the radiosensitivity of fractionally irradiated and non-irradiated cells was similar. Including transient radioresistance, described as (α/β) -( d +1) , as a factor in the classic LQ model resulted in a perfect fit with the experimental data observed during fractionated radiotherapy. This was confirmed when different dose fractions were applied.
Conclusions: Fractionated irradiation of cancer cells in vitro following clinical radiation schedules induces a reversible radioresistance response. This adaptive response can be included in the LQ model as a function of the dose fraction and the alpha/beta-ratio of a given cell line. These findings warrant further investigation of the mechanisms and clinical relevance of adaptive radioresistance.
(Copyright © 2020 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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