Triple-negative breast cancer (TNBCs) account for 15-20% of all breast
cancers and represent the most aggressive subtype of this
malignancy. Early
tumor relapse and progression are linked to the enrichment of a sub-fraction of
cancer cells, termed
breast tumor-initiating cells (BTICs), that undergo epithelial to mesenchymal transition (EMT) and typically exhibit a basal-like CD44high/CD24low and/or ALDH1high phenotype with critical
cancer stem-like features such as high self-renewal capacity and intrinsic (de novo) resistance to standard of care
chemotherapy. One of the major mechanisms responsible for the intrinsic drug resistance of BTICs is their high ALDH1 activity leading to inhibition of
chemotherapy-induced apoptosis. In this study, we demonstrated that
aurora-A kinase (
AURKA) is required to mediate TGF-β-induced expression of the SNAI1 gene, enrichment of ALDH1high BTICs, self-renewal capacity, and chemoresistance in TNBC experimental models. Significantly, the combination of
docetaxel (DTX) with dual TGF-β and
AURKA pharmacologic targeting impaired
tumor relapse and the emergence of distant
metastasis. We also showed in unique chemoresistant TNBC cells isolated from patient-derived TNBC brain
metastasis that dual TGF-β and
AURKA pharmacologic targeting reversed
cancer plasticity and enhanced the sensitivity of TNBC cells to DTX-based-
chemotherapy. Taken together, these findings reveal for the first time the critical role of
AURKA oncogenic signaling in mediating TGF-β-induced TNBC plasticity, chemoresistance, and
tumor progression.