Compared to individuals on Earth, astronauts receive much higher doses of ionizing radiation during space flight. Besides this, the radiation quality in space in different from the typical low-linear energy transfer (LET) terrestrial radiation (e.g. X-rays, y-rays), and mainly consists of high-energy protons and highly charged and energetic (HZE) particles. These high-LET particles are predicted to account for most of the biological consequences after cosmic radiation exposure, and are of critical concern to risk assessment for astronauts. Further detailed analysis of the biological effects of HZE nuclei on human cells is therefore essential. Within the current CORALS contract, different human cell lines were exsposed to heavy ions (Ni ions in particular) in order to investigate the effects at the cellular level. The main aim of the follow-up of the CORALS project is to further analyse, interprete and hopefully conclude on the biological effects of nickel ion beams (irradiation performed at GSI in Darmstadt, Germany) in terms of pre-mRNA splicing, DNA damage and cytokine secretion in human cell types exposed in vitro. These results will then be compared to the effects of X-ray exposure.