The goal of the present article was to determine whether a nuclear parameter, centromere structure of interphase cells, could serve as an
indicator to assess cellular damage caused by anti-
tumor drugs. These were cis-platin and
mafosfamide, which are widely used for the management of solid
tumors. To visualize the centromeres, we probed treated and untreated cells of a human
breast cancer cell line, MX-1, with a human anti-centromere serum. The serum was obtained from a scleroderma patient and detects
antigens associated with prekinetochores of the decondensed chromosomes. The
DNA was simultaneously displayed by a specific
fluorescent dye. The cells were grown on coverslips, incubated for 1 h in a
drug-containing medium, transferred into a
drug-free medium and observed 24 h later. Since the efficiency of many anti-
tumor drugs increases with the temperature, two different temperatures, 37 and 42 degrees C, were used. The analysis revealed that the treatment did not visibly alter the labeling pattern. We conclude that chromosome structure remains largely intact and is not suitable for the cytological evaluation of the efficiency of anti-
tumor drugs. This is in contrast with, for example, the microtubular cytoskeleton and mitochondria, which were extensively damaged under the conditions applied here (compare Wolf et al. 1995). Independent of the
drug and the temperature selected, the nuclear lumen of mononucleated and multinucleated cells contained small fluorescent spots. Double dots corresponding to the sister centromeres in the G2 phase of the cell cycle were rare. In addition to the voluminous nuclei, some cells possessed micronuclei in the lateral cytoplasm and these were regularly labeled by the
autoantibodies. A small subset of the mononucleated MX-1 cells had unusually large nuclei. It is reasonable to assume that they are
polyploid. The fluorescent spots marking the prekinetochores were very large in these cells. This may indicate that the chromosomes remain associated after replication.