The effects of doxorubicin on embryonic spinal motoneurons cultured in vitro: cytoskeletal response.

The interaction of doxorubicin with tubulin in spinal motoneuronal cells cultured in vitro has been examined by laser scan microscopy with an immunocytological double staining technique, and by biochemical analysis. Results obtained by laser scan microscopy indicate that doxorubicin (2 x 10(-8) M) was able to induce fragmentation or disappearance of microtubules in motoneuronal cells. Motoneurons were identified by their positivity to anti-CAT antibody. This observation was then studied by biochemical analysis on purified calf brain tubulin. Even treatment with a high dose of doxorubicin (1.2 x 10(-5) M) does not impair tubulin polymerization. The finding supports the possibility that doxorubicin interacts with MAPs or other polypeptides present in the cytomatrix that coassemble with tubulin and are necessary for microtubule formation.