title: βIII-Tubulin is required for interphase microtubule dynamics in untransformed human mammary epithelial cells.
abstract: Numerous works have questioned the pertinence of using βII- and/or βIII-tubulin expression as markers of prognosis and/or prediction of breast cancer response to chemotherapy containing microtubule-targeting agents. The rationale of such studies was essentially based on microtubule dynamics analysis using purified tubulin in vitro and cancer cell lines. Nonetheless, the significance of βII- and βIII-tubulin expression in the control of microtubule dynamics in normal mammary epithelium has never been addressed. Here we investigate the expression and the consequences of βII- and/or βIII-tubulin depletion in interphase microtubule dynamics in non-tumor human mammary epithelial cells. We find that both isoforms contribute to the tubulin isotype composition in primary and immortalized human mammary epithelial cells. Moreover, while βII-tubulin depletion has limited effects on interphase microtubule behavior, βIII-tubulin depletion causes a strong exclusion of microtubules from lamella and a severe suppression of dynamic instability. These results demonstrate that, while βII-tubulin is dispensable, βIII-tubulin is required for interphase microtubule dynamics in untransformed mammary epithelial cells. This strongly suggests that βIII-tubulin is an essential regulator of interphase microtubule functions in normal breast epithelium cells.
authors.affiliation: Université de Lyon, F-69000 Lyon, France. bouchetben@gmail.com
authors.forename: Benjamin Pierre
authors.initials: BP
authors.lastname: Bouchet
authors.forename: Alain
authors.initials: A
authors.lastname: Puisieux
authors.forename: Carlos María
authors.initials: CM
authors.lastname: Galmarini
mesh_terms: D002478:Cells, Cultured; D005260:Female; D055785:Gene Knockdown Techniques; D006801:Humans; D007399:Interphase; D042361:Mammary Glands, Human / Q000166:cytology*; D008870:Microtubules / Q000378:metabolism*; D061251:Primary Cell Culture; D034622:RNA Interference; D059010:Single-Cell Analysis; D014404:Tubulin / Q000235:genetics / Q000378:metabolism*
chemical_list: C498585:TUBB3 protein, human; D014404:Tubulin