Vinorelbine induces beta3-tubulin gene expression through an AP-1 Site.

Although the correlation between beta3-tubulin expression level in tumors has been well correlated with clinical outcome in patients receiving microtubule-targeted agents, the regulation of this protein remains poorly understood. Recently, new insight of regulatory processes was offered with the cloning of the gene promoter. In this study beta3-tubulin gene expression was induced in response to exposure to various antimicrotubule agents such as vinorelbine and paclitaxel. The exploration of the beta3-tubulin gene promoter by successive deletions followed by site-directed mutagenesis led to the localization of a vinorelbine-responsive element containing an activator-protein 1 (AP-1) site. Among the various antimicrotubule agents tested, it appeared that the implicated AP-1 site was activated only after exposure to vinorelbine. This study confirms the inducible nature of the beta3-tubulin gene promoter.