Chromosome aberrations induced by high-LET carbon ions in radiosensitive and radioresistant tumour cells

Chromosome aberration formation was analysed in two human tumour cell lines displaying different radiosensitivity. Aberrations involving chromosomes 2, 4, and 5 were studied in one radioresistant cell line (WiDr) and in one radiosensitive cell line (MCF-7). Chromosome aberrations were studied by application of single-colour FISH. We studied the effects of monoenergetic 100 MeV/u carbon ions and carbon ions from extended Bragg peak. Chromosome aberrations induced by carbon ions were compared with aberrations induced by standard 200 kV X-rays. In both tumour cell lines, carbon ions induced aberrations more effectively than X-rays. The radioresistance and radiosensitivity of the corresponding cell lines, as observed for X-rays, were also found after carbon ion irradiation. In both cell lines, the typical effects of ion irradiation were an increased proportion of cells containing complex aberrations, and an increased complexity of these complex exchanges. However, comparable effects were induced in MCF-7 cells by a much lower dose than in WiDr cells. Insertions were also induced more efficiently in MCF-7 cells than in WiDr cells.