Establishment of proliferative tetraploid cells from telomerase‐immortalized normal human fibroblasts

Aneuploidy is observed in the majority of human cancers and is considered to be causally related to carcinogenesis. Although malignant aneuploid cells are suggested to develop from polyploid cells formed in precancerous lesions, the mechanisms of this process remain elusive. This is partly because no experimental model is available where nontransformed polyploid human cells propagate in vitro. We previously showed that proliferative tetraploid cells can be established from normal human fibroblasts by treatment with the spindle poison demecolcine (DC). However, the limited lifespan of these cells hampered detailed analysis of a link between chromosomal instability and the oncogenic transformation of polyploid cells. Here, we report the establishment of proliferative tetraploid cells from the telomerase‐immortalized normal human fibroblast cell line TIG‐1. Treatment of immortalized diploid cells with DC for 4 days resulted in proliferation of cells with tetraploid DNA content and near‐tetraploid/tetraploid chromosome counts. Established tetraploid cells had functional TP53 despite growing at almost the same rate as diploid cells. The frequency of clonal and sporadic chromosome aberrations in tetraploid cells was higher than in diploid cells and in one experiment, gradually increased with repeated subculture. This study suggests that tetraploid cells established from telomerase‐immortalized normal human fibroblasts can be a valuable model for studying chromosomal instability and the oncogenic potential of polyploid cells. © 2016 Wiley Periodicals, Inc.