Cahiers de radiobiologie1998 Aug;7(8):12-23
Cancer Research Group, Medical Physics, Ottawa Regional Cancer Centre, Ottawa, Canada.
The feasibility of chemically-induced premature chromosome condensation (PCC) was tested in two human fibroblast and two human malignant melanoma cell lines. To induce PCCs, a potent protein phosphatase inhibitors, was used at a final concentration of 80 nM. Attached cells and cells put into suspension by trypsinization were incubated with calyculin A at 37 oC for 1 hour. Calyculin A was able to induce PCCs in all the phase of the cell cycle with the tumor cell lines giving the highest PCC frequency. No systematic differences were observed between attached cells and cells put into suspension by trypsinization. However, a cytotoxic effect was more severe in the fibroblast than in the tumor cell lines. The appearance of deformed, fragile and fragmented nuclei with no particular chromatin condensation would explain to some extent this cytotoxic effect. A better understanding of the mechanism of action of calyculin A would help generalizing its use to study interphase chromosome aberrations.