Aurora B induces epithelial-mesenchymal transition by stabilizing Snail1 to promote basal-like breast cancer metastasis.

Aurora B is a serine/threonine kinase that has been implicated in regulating cell proliferation in distinct cancers, including breast cancer. Here we show that Aurora B expression is elevated in basal-like breast cancer (BLBC) compared with other breast cancer subtypes. This high level of expression seems to correlate with poor metastasis-free survival and relapse-free survival in affected patients. Mechanistically, we show that elevated Aurora B expression in breast cancer cells activates AKT/GSK3β to stabilize Snail1 protein, a master regulator of epithelial-mesenchymal transition (EMT), leading to EMT induction in a kinase-dependent manner. Conversely, Aurora B knock down by short-hairpin RNAs (shRNAs) suppresses AKT/GSK3β/Snail1 signaling, reverses EMT and reduces breast cancer metastatic potential in vitro and in vivo. Finally, we identified a specific OCT4 phosphorylation site (T343) responsible for mediating Aurora B-induced AKT/GSK3β/Snail1 signaling and EMT that could be attenuated by Aurora B kinase inhibitor treatment. These findings support that Aurora B induces EMT to promote breast cancer metastasis via OCT4/AKT/GSK3β/Snail1 signaling. Pharmacologic Aurora B inhibition might be a potential effective treatment for breast cancer patients with metastatic disease.