Modem therapy of solid tumors involves drugs such as cisplatin (CDDP) and mafosfamide (MAFO) that interact with the DNA. Hyperthermia facilitates the effectiveness of these drugs for the management of aggressive metastatic tumors. To evaluate the extent of cellular damage caused by anti-tumor drugs under hyperthermic conditions, we have examined the microtubular cytoskeleton in a human breast cancer line, MX-1, at two different temperatures: 37 and 42 degrees C. A mouse monoclonal antibody to beta-tubulin and a rabbit polyclonal antibody to gamma-tubulin were used in combination with indirect immunofluorescence. The former antibody stains the entire microtubular cytoskeleton, whereas the latter antibody detects microtubule-organizing centres. Untreated cells possessed a rich interphase cytoskeleton. The antibody against gamma-tubulin detected one to two distinct spots in mononucleate cells and a cluster of spots in multinucleate cells. Microtubules were usually not focused towards the gamma-tubulin-containing material. At 42 degrees C more cells were damaged when compared with cells treated at 37 degrees C. The drug effects were, however, highly variable. There were cells that appeared unaffected by a single treatment while other cells had almost completely lost their microtubules. Concomitantly, gamma-tubulin-containing clumps had formed in the highly damaged cells. Electron microscopy of ultrathin sections revealed a range of structural changes of cytoplasmic components including mitochondrial defects after CDDP treatment.

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