Tumor cell migration is not influenced by p21 in colon carcinoma cell lines after irradiation with X-ray or 12C heavy ions

Metastasis and recurrences are major problems regarding an effective treatment of solid malignant tumors in clinical oncology. Since the impact of radiation on cell motility is not yet well understood, intrinsic and radiation-induced changes in cell migration have been discussed as possible mechanisms involved in the limitations of radiotherapy. This holds true for conventional radiation treatment and even more for the cellular and molecular effects of therapeutically relevant 12C heavy ions. The present study is therefore focused on the investigation of tumor cell migration in vitro after irradiation with X-rays and 12C heavy ions and on radiation-induced changes in the expression of proteins that are potentially relevant for motility. Two colon carcinoma cell lines, HCT116 and HCT116 p21−/−, were chosen for this study, which should be isogenic except for their p21-status. We can show here that cells lacking p21 react almost alike to radiation as wild type cells regarding survival and tumor cell migration 24 h after irradiation. Interestingly, differences in protein expression 24 h after irradiation of β1 integrin and protein kinase B isoforms Akt1 and Akt2 seem to exist. We conclude that tumor cell migration is unaffected by the p21-status in colorectal carcinoma cells and that the expression of the aforementioned proteins alone is not accountable for the differences observed.