Biological Effectiveness of Carbon-Ion Radiation on Various Human Breast Cancer Cell Lines
- *Corresponding Author:
- Kumiko Karasawa
Research Center Hospital for Charged Particle Therapy
National Institute of Radiological Sciences
4-9-1 Anagawa, Inageku, Chiba-city, Chiba, 263-8555, Japan
Tel: +81432063306 ext 6208
E-mail: [email protected]
Received Date: July 28, 2014; Accepted Date: September 25, 2014; Published Date: September 27, 2014
Citation: Karasawa K, Fujita M, Shoji Y, Horimoto Y, Inoue T, et al. (2014) Biological Effectiveness of Carbon-Ion Radiation on Various Human Breast Cancer Cell Lines. J Cell Sci Ther 5:180. doi: 10.4172/2157-7013.1000180
Copyright: © 2014 Karasawa K, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Introduction: Carbon-ion radiotherapy (C-ion RT) is known as a highly effective local treatment and its relative biological effectiveness (RBE) has been evaluated for various types of malignant tumors. There are only a few studies on C-ion radio sensitivity in breast cancer, and there has been no evaluation by subtypes. To estimate the impact of C-ion RT for breast cancer, RBE of C-ion beams of various types of human breast cancer cell lines was evaluated by comparison with X-rays.
Methods: Six human breast cancer cell lines with different subtypes, Luminal-human epidermal growth factor receptor 2 (HER2)-negative (MCF-7), Luminal-HER2-positive (BT-474), Her2-enriched (SK-BR-3), Basal-like (MDAMB- 468, HCC1937) and ductal carcinoma in situ (MCF10DCIS.com) were used. Radio sensitivities were assessed with survival curves created from colony-forming assay (CFA) and high-density surviving assay (HDS). An X-ray generator was used with 200 kV, 20 mA. The Heavy Ion Medical Accelerator in Chiba (HIMAC) was used for C-ion irradiation, with 290 MeV/u, mono-peak, linear energy transfer (LET) of 80 KeV/μm.
Results: CFA was not suitable for BT474, SK-BR-3, MDA-MB-468, and HCC1937 because of their low plating efficiency. The differences between the D10 values on HDS were large with X-ray, and the survival curve shoulders for MCF7, MDA-MB-468, and MCF10DCIS.com were wide. On the other hand, the differences between the D10 values were small with C-ion beams, and the survival curves were linear without shoulders for all cell lines except a small shoulder with MCF10DCIS.com. The RBE value of C-ion beams was 2.3 to 3.6, median 2.9 in all cell lines by CFA and HDS.
Conclusion: RBE around 3 by C-ion beams was seen in many types of ductal cancer. The small survival curve shoulder on MCF10DCIS.com suggested that non invasive ductal carcinoma is relatively more resistant than invasive cancer.