Light, fluorescent, and electron microscopic analysis of cultured breast tumor cells (T-47D) treated with 9,10-anthracenedicarboxaldehyde bis[(4,5-dihydro-1H-imidazol-2-yl)hydrazone] dihydrochloride.

The influence of bisantrene on T-47D human breast tumor cells was assessed by colony-forming assay in soft agar and by light, fluorescence, and electron microscopy. Test solutions of bisantrene solubilized in distilled water or dimethyl sulfoxide were added to cultures at final concentrations between 0.01 and 60 micrograms/ml. Brightly fluorescent particles appeared in a concentration-dependent fashion after cultures were treated with water-soluble bisantrene at concentrations greater than 0.1 microgram/ml. Similar fluorescent crystals appeared in culture media when concentrations of the dimethyl sulfoxide-dissolved drug exceeded 10 micrograms/ml. Clonogenic survival as defined by soft agar assay indicated significant reproductive impairment in cells treated with concentrations greater than 1 micrograms/ml (p less than 0.01). Nuclear and cytoplasmic fluorescence was evident in treated cells. Cells that survived 24-hr drug treatment displayed round nuclei with watery nucleoplasm when examined under the light microscope. Under the electron microscope, nuclei of these cells revealed fragmentation of the nucleolar complex and a highly electron-lucent nucleoplasm. Cytoplasmic responses, which seem to be relatively innocuous, include incorporation of the fluorescent crystals into lysosomes and some mitochondrial abnormalities. Crystalline inclusions engulfed by lysosomes were found in cells obtained from cultures showing bisantrene precipitates.