Cellular Radiosensitivity of Soft Tissue Sarcoma

Radiation Research, vol. 196, pp. 23–30

Abstract

Currently, all soft tissue sarcomas (STS) are irradiated by the same regimen, disregarding possible subtype-specific radiosensitivities. To gain further insight, cellular radiosensitivity was investigated in a panel of sarcoma cell lines. Fourteen sarcoma cell lines, derived from synovial sarcoma, leiomyosarcoma, fibrosarcoma and liposarcoma origin, were submitted to clonogenic survival assays. Cells were irradiated with single doses from 1-8 Gy and surviving fraction (SF) was calculated from the resulting response data. Alpha/beta (α/β) ratios were inferred from radiation-response curves using the linear-quadratic (LQ)-model. Cellular radiosensitivities varied largely in this panel, indicating a considerable degree of heterogeneity. Surviving fraction after 2 Gy (SF2) ranged from 0.27 to 0.76 with evidence of a particular radiosensitive phenotype in only few cell lines. D37% on the mean data was 3.4 Gy and the median SF2 was 0.52. The median α/β was 4.9 Gy and in six cell lines the α/β was below 4 Gy. A fairly homogeneous radiation response was observed in myxoid liposarcoma cell lines with SF2 between 0.64 and 0.67. Further comparing sarcomas of different origin, synovial sarcomas, as a group, showed the lowest SF2 values (mean 0.35) and was significantly more radiosensitive than myxoid liposarcomas and leiomyosarcomas (P = 0.0084 and 0.024, respectively). This study demonstrates a broad spectrum of radiosensitivities across STS cell lines and reveals subtype-specific radiation responses. The particular cellular radiosensitivity of synovial sarcoma cells supports consideration of the different sarcoma entities in clinical studies that aim to optimize sarcoma radiotherapy.

Authors 10

1. Rick L. Haas corresponding
   Affiliation as printed

   Department of Radiotherapy

2. B.G.J. Floot
   Affiliation as printed

   Department of Surgical Oncology

3. Astrid N. Scholten
   Affiliation as printed

   Department of Radiotherapy

4. Winette T.A. van der Graaf
   Affiliation as printed

   Division of Cell Biology

5. Winan J. van Houdt
   Affiliation as printed

   Department of Medical Oncology

6. Yvonne M. Schrage
   Affiliation as printed

   Department of Medical Oncology

7. Marieke van de Ven

   The Netherlands Cancer Institute

   Affiliation as printed

   Preclinical Intervention Unit, Mouse Clinic for Cancer and Aging (MCCA), The Netherlands Cancer Insititute, Amsterdam, The Netherlands

8. Judith V.M.G. Bovée Aachen Department of Pathology, Leiden University Medical Centre

   Leiden University · Leiden University Medical Center

   Affiliation as printed

   Department of Pathology, Leiden University Medical Centre, Leiden, the Netherlands

9. Frits van Coevorden
   Affiliation as printed

   Department of Medical Oncology

10. Conchita Vens
    Affiliation as printed

    Department of Radiotherapy

    Department of Surgical Oncology