Taxol reduces cytosolic E-cadherin and beta-catenin levels in nasopharyngeal carcinoma cell line TW-039: Cross-talk between the microtubule- and actin-based cytoskeletons

Taxol affects microtubule dynamics by promoting microtubule assembly. To ob tain a better insight into possible cross-talk between the microtubule- and actin-based cytoskeletons, we studied the short-term effects of Taxol trea tment on the expression of actin and the E-cadherin/catenin complex in the nasopharyngeal carcinoma cell line TW-039 using immunofluorescence, immunop recipitation, and immunoblotting methods. Morphologic changes in actin fila ments, including ventral actin clumps and perijunctional actin blebs, were seen at Taxol concentrations greater than or equal to1 muM. Levels of deter gent-soluble E-cadherin fell to 53% or 58% compared to controls in cells tr eated, respectively, with 1 or 5 muM Taxol, while levels of detergent-solub le beta -catenin fell to 76% or 74%. Levels of the detergent-soluble pool o f alpha- and gamma -catenin and the detergent-insoluble pool of the E-cadhe rin/catenin complex were unchanged by Taxol treatment and no significant di fference was seen in the levels of adenomatous polyposis coli or glycogen s ynthase-3 beta or tyrosine phosphorylation patterns. These results suggest that modulation of microtubule dynamics by Taxol may have effects on the ex pression of actin and the cytosolic E-cadherin and beta -catenin in nasopha ryngeal carcinoma cells through pathways not involving the phosphorylation of beta -catenin. (C) 2000 Wiley-Liss. Inc.