Chromosomal instability of tetraploid cells established from telomerase-immortalized normal human fibroblasts

Abstract

This article provides evidence that tetraploid cells are chromosomally unstable compared with diploid cells. We used telomerase-immortalized TIG-1 human fibroblasts and their tetraploid derivatives, established using our method. Tetraploid cells and original diploid cells were treated with the carcinogen 1-methyl-3-nitro-1-nitrosoguanidine (MNNG) or the spindle poison demecolcine (DC) for one day. Clones developed from single cells after each treatment were isolated, and chromosome counts and karyotypes in clonal cells were analyzed. Clones developed from DC-treated tetraploid cells showed greater variation in modal chromosome numbers compared with clones developed from DC-treated diploid cells. Karyotype analysis showed a higher frequency of structural chromosome aberrations in clones developed from DC-treated tetraploid cells compared with clones developed from DC-treated diploid cells. The data reveal the usefulness of tetraploid cells established by our protocol as a model for studying chromosomal instability of polyploid cells.