Heavy ion-induced differentiation of normal human fibroblasts

Abstract

Potential advantage of greater biological effectiveness and excellent dose distribution over conventional low-LET radiations represents the rational for the clinical usage of high-LET heavy ions. Unavoidable, however, is exposure of normal cells that coexist with or surround tumors. Whereas fibrosis following radiotherapy is known to result from augmented differentiation of normal cells, the effect of heavy ions on differentiation is unknown. To address this, we have investigated the morphological differentiation of normal human fibroblasts irradiated with gamma-rays (0.2 keV/μm) or carbon ions (108 keV/μm). We found that carbon ions were fourfold more effective at inducing morphological differentiation at 5 days post-irradiation. Further experiments to examine the LET dependence of augmented differentiation and its underlying mechanism(s) are ongoing.