Function of Aurora kinase A in Taxol-resistant breast cancer and its correlation with P-gp.

Breast cancer is one of the most common malignant diseases among women. In early and metastatic breast cancer, Taxane (Taxol) is widely used as an adjuvant and neoadjuvant therapies. Although breast cancer is initially responsive to Taxol, inherent or developed resistance to Taxol often limits the efficacy of the drug. The oncogene Aurora kinase A is frequently up-regulated in human cancer, and is associated with sensitivity to chemotherapy in certain types of cancer. In the present study, we aimed to clarify the functional role of Aurora kinase A in breast cancer resistance to Taxol, and to determine the means to overcome this resistance. The correlation between the expression levels of Aurora kinase A and chemoresistance to Taxol in breast cancer cells, and resistance to Taxol in a xenograft model were demonstrated. MTT assay was performed to determine cell viability. Subsequently, the relationship of Aurora kinase A with the expression and functional role of P-gp was clarified, as well as its relationship with p-ERK2, which regulates the expression of P-gp. The expression of Aurora A was determined to be capable of enhancing the sensitivity of cells resistant to Taxol in vitro and in vivo using stable knockdown Aurora kinase A cells. We propose that this kinase may be used as a target for overcoming chemoresistance and enhancing the chemosensitivity of breast cancer to Taxol.