| Abstract: | The effect of taxol, an experimental anti-tumor drug which exerts its effect through an action on the microtubular system, has been followed on the pheochromocytoma clonal cell line (PC12). Cells exposed to this drug, within 2–3 days, cease division and detach from the substratum. When nerve growth factor (NGF) is also present, PC 12 cells not only survive taxol treatment, but they also grow neuntes much larger than those emerging from cells incubated with NGF alone. At the ultrastructural examination, NGF-taxol-treated cells show the presence of an exceedingly large number of microtubules filling the cytoplasm even at the expense of other filamentous structures. These findings show that massive microtubule accumulation induced by taxol leads to rapid mitotic arrest, but is not sufficient to induce morphological differentiation of PC12 cells which requires also the presence of NGF. |
