In vitro characterization of radiotherapy-induced morphonuclear modifications on chemosensitive as opposed to chemoresistant neoplastic cells

Abstract

Purpose: We describe by means of digital cell image analysis the influence of X-ray radiation on three in vitro cultured cell lines for which we set up chemosensitive and chemoresistant variants.

Methods and materials: The three cell lines correspond to the MXT mouse mammary and the T24 and J82 neoplastic human bladder cells. The digital cell image analysis was carried out by computing morphometric (nuclear size), densitometric (proportion of cells in the G2 cell cycle phase), and textural features (chromatin pattern characteristics) on Feulgen-stained nuclei.

Results: The results show that such digital cell image analyses make it possible to monitor radiotherapy-induced effects on these morphonuclear characteristics accurately. X-ray radiotherapy induces a dose-dependent increase in the proportion of cells in the G2 phase of the cell cycle along with a decrease in the overall chromatin condensation level. These two concomitant phenomena lead to a marked radiotherapy-induced increase in nuclear size. We also observed that radiotherapy-induced effects at the morphonuclear level are not only highly specific to the cell type analyzed, that is MXT mouse mammary or J82 or T24 human bladder carcinoma cells, but also to the fact that the cells are either chemosensitive or chemoresistant.

Conclusion: The digital cell image analyses of Feulgen-stained nuclei is helpful in monitoring the irradiation-induced morphonuclear modifications.