EFFECTS OF CISPLATIN AND MAFOSFAMIDE ON THE INTERPHASE MICROTUBULAR CYTOSKELETON OF A HUMAN BREAST-CANCER CELL-LINE, MX-1, IN-VITRO - A FINE-STRUCTURE AND ANTITUBULIN IMMUNOFLUORESCENCE STUDY

Modem therapy of solid tumors involves drugs such as cisplatin (CDDP) and mafosfamide (MAFO) that interact with the DNA. Hyperthermia facili tates the effectiveness of these drugs for the management of aggressiv e metastatic tumors. To evaluate the extent of cellular damage caused by anti-tumor drugs under hyperthermic conditions, we have examined th e microtubular cytoskeleton in a human breast cancer line, MX-1, at tw o different temperatures: 37 and 42 degrees C. A mouse monoclonal anti body 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 lat ter antibody detects microtubule-organizing centres. Untreated cells p ossessed a rich interphase cytoskeleton. The antibody against gamma-tu bulin detected one to two distinct spots in mononucleate cells and a c luster 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 degree s 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-tubuli n-containing clumps had formed in the highly damaged cells. Electron m icroscopy of ultrathin sections revealed a range of structural changes of cytoplasmic components including mitochondrial defects after CDDP treatment.