2-Methoxyestradiol Induces Morpho-Functional Changes and Alteration of Tubulin Dynamics in Mouse Neuroblastoma and Rat Glioma Cells

Abstract

2-Methoxyestradiol (2ME), a metabolite of 17-beta estradiol, has a high antiangiogenic, apoptotic and antiproliferative activity both in several cell lines and tumour models. Moreover, 2ME may exert its activity not only interacting with tubulin and inhibiting tubulin polymerization but also altering tubulin dynamics. This study was aimed at finding the possible differences in the relative effectiveness of 2ME on mouse neuroblastoma (C1300) and rat glioma (C6) cell lines in inducing morpho-functional changes and alterations of tubulin dynamics. Cells were cultured in a medium supplemented with increasing 2ME micromolar concentrations, underwent morphological investigations and Western Blot analyses. Both cell lines were sensitive to 2ME displaying morpho-functional changes such as nuclear suffering, decreased viability and growth inhibition but all alterations were more marked in C1300 than in C6 cells. Western Blot analyses showed that total and tyrosinated α-tubulin expression were down-regulated more intensely in C1300 than in C6 cells, whereas acetylated α-tubulin expression was not down-regulated in both cell lines. Our results point out that 2ME is more effective in neural cells than in glial cells. The dramatic alteration of the expression of total and mainly tyrosinated α-tubulin suggests that 2ME effectiveness could be related to an alteration of tubulin dynamics resulting in changed microtubule growth parameters and block of mitosis.