FIGURE 1:

Establishment of DLD-1–derived lines differing in ploidy. (A) Schematic summarizing the generation, properties, and analysis of DLD-1 colon cancer cell lines. Starting from a diploid (2N) parental culture, tetraploid (4N) cells were obtained by inhibition of cytokinesis. The 4N cells were then used for clonal isolation of posttetraploid aneuploid (PTA) descendants. Clones harboring trisomies of chromosome 7 (Tr7) were generated from the diploid parental culture by microcell-mediated chromosome transfer. (B) Histograms document the DNA profiles of the cell lines used in this study. Cells were stained with propidium iodine and subjected to analysis by flow cytometry. Dotted lines indicate the G1 and G2/M peaks expected for the diploid culture. (C) Top panel: micrographs depict mitotic spreads of the indicated cell lines; chromosomes were stained with DAPI. Bottom panel: histograms show chromosome numbers for each cell line, with bars and numbers indicating mean values; at least 40 cells were counted for each line. Data represent results from three biological replicates. Scale bar denotes 10 μm.