TREATMENT WITH THE ANTITUMOR DRUGS, CISPLATIN AND MAFOSFAMIDE, DOES NOT AFFECT THE STRUCTURE OF PREKINETOCHORES IN A HUMAN BREAST-CANCER CELL-LINE - AN IMMUNOFLUORESCENCE STUDY USING HUMAN ANTICENTROMERE AUTOANTIBODIES

The goal of the present article was to determine whether a nuclear par ameter, centromere structure of interphase cells, could serve as an in dicator to assess cellular damage caused by anti-tumor drugs. These we re cis-platin and mafosfamide, which are widely used for the managemen t of solid tumors. To visualize the centromeres, we probed treated and untreated cells of a human breast cancer cell line, MX-1, with a huma n anti-centromere serum. The serum was obtained from a scleroderma pat ient and detects antigens associated with prekinetochores of the decon densed chromosomes. The DNA was simultaneously displayed by a specific fluorescent dye. The cells were grown on coverslips, incubated for Ih in a drug-containing medium, transferred into a drug-free medium and observed 24 h later. Since the efficiency of many anti-tumor drugs inc reases with the temperature, two different temperatures, 37 and 42 deg rees C, were used. The analysis revealed that the treatment did not vi sibly alter the labeling pattern. We conclude that chromosome structur e remains largely intact and is not suitable for the cytological evalu ation of the efficiency of anti-tumor drugs. This is in contrast with, for example, the microtubular cytoskeleton and mitochondria, which we re extensively damaged under the conditions applied here (compare Wolf et al. 1995). Independent of the drug and the temperature selected, t he nuclear lumen of mononucleated and multinucleated cells contained s mall fluorescent spots. Double dots corresponding to the sister centro meres in the G(2) phase of the cell cycle were rare. In addition to th e voluminous nuclei, some cells possessed micronuclei in the lateral c ytoplasm and these were regularly labeled by the autoantibodies. A sma ll subset of the mononucleated MX-1 cells had unusually large nuclei. It is reasonable to assume that they are polyploid. The fluorescent sp ots marking the prekinetochores were very large in these cells. This m ay indicate that the chromosomes remain associated after replication.