The mitotic kinase Aurora-A (Aur-A) is required to form the bipolar spindle and ensure accurate chromosome segregation before cell division. Aur-A dysregulation represents an oncogenic event that promotes tumor formation. Here, we report that Aur-A promotes breast cancer metastasis. Aur-A overexpression enhanced mammary cell migration by dephosphorylation and activation of cofilin, which facilitates actin reorganization and polymerization. Cofilin knockdown impaired Aur-A-driven cell migration and protrusion of the cell membrane. Conversely, overexpression of activated cofilin abrogated the effects of Aur-A knockdown on cell migration. Moreover, Aur-A overexpession increased the expression of the cofilin phosphatase Slingshot-1 (SSH1), contributing to cofilin activation and cell migration. We found that phosphatidylinositol 3-kinase (PI3K) inhibition blocked Aur-A-induced cofilin dephosphorylation, actin reorganization, and cell migration, suggesting crosstalk with PI3K signaling and a potential benefit of PI3K inhibition in tumors with deregulated Aur-A. Additionally, we found an association between Aur-A overexpression and cofilin activity in breast cancer tissues. Our findings indicate that activation of the cofilin-F-actin pathway contributes to tumor cell migration and metastasis enhanced by Aur-A, revealing a novel function for mitotic Aur-A kinase in tumor progression. Cancer Res; 70(22); 9118-28. ©2010 AACR.

Lack of cellular differentiation is a key feature of nasopharyngeal carcinoma (NPC), but it also presents as a unique opportunity for intervention by differentiation therapy. Here using RNA-seq profiling analysis and functional assays, we demonstrate that reduced IKKa expression is responsible for the undifferentiated phenotype of NPC. Conversely, overexpression of IKKa induces differentiation and reduces tumorigenicity of NPC cells without activating NF-kB signalling. Importantly, we describe a mechanism whereby EZH2 directs IKKa transcriptional repression via H3K27 histone methylation on the IKKa promoter. The differentiation agent, retinoic acid, increases IKKa expression by suppressing EZH2-mediated H3K27 histone methylation, resulting in enhanced differentiation of NPC cells. In agreement, an inverse correlation between IKKa (low) and EZH2 (high) expression is associated with a lack of differentiation in NPC patient samples. Collectively, these findings demonstrate a role for IKKa in NPC differentiation and reveal an epigenetic mechanism for IKKa regulation, unveiling a new avenue for differentiation therapy.

Triple negative breast cancer (TNBC) acquires an unfavorable prognosis, emerging as a major challenge for the treatment of breast cancer. In the present study, 122 TNBC patients were subjected to analysis of Aurora-A (Aur-A) expression and survival prognosis. We found that Aur-A high expression was positively associated with initial clinical stage (P = 0.025), the proliferation marker Ki-67 (P = 0.001), and the recurrence rate of TNBC patients (P<0.001). In TNBC patients with Aur-A high expression, the risk of distant recurrence peaked at the first 3 years and declined rapidly thereafter, whereas patients with Aur-A low expression showed a relatively constant risk of recurrence during the entire follow-up period. Univariate and multivariate analysis showed that overexpression of Aur-A predicted poor overall survival (P = 0.002) and progression-free survival (P = 0.012) in TNBC. Furthermore, overexpression of Aur-A, associated with high Ki-67, predicted an inferior prognosis compared with low expression of both Aur-A and Ki-67. Importantly, we further found that Aur-A was overexpressed in TNBC cells, and inhibition of this kinase inhibited cell proliferation and prevented cell migration in TNBC. Our findings demonstrated that Aur-A was a potential therapeutic target for TNBC and inhibition of Aur-A kinase was a promising regimen for TNBC cancer therapy.

BackgroundPlatinum-based chemotherapy improves survival among patients with non-small cell lung cancer (NSCLC), but the efficiency is limited due to resistance. In this study, we aimed to identify the expression of Aurora-A and its correlation with cisplatin resistance and prognosis in NSCLC.MethodsWe used immunohistochemical analysis to determine the expression of Aurora-A protein in 102 NSCLC patients treated by surgery and adjuvant cisplatin-based chemotherapy. The prognostic significances were assessed by Kaplan-Meier survival estimates and Cox models. The potential role of Aurora-A in the regulation of cisplatin resistance in NSCLC cells was examined by transfections using expression vector and small interfering RNA or using small-molecule inhibitors.ResultsAurora-A expression was significantly associated with clinical stage (p = 0.018), lymph node metastasis (p = 0.038) and recurrence (p = 0.005), and was an independent prognostic parameter in multivariate analysis. High level of Aurora-A expression predicted poorer overall survival (OS) and progression-free survival (PFS). In vitro data showed that Aurora-A expression was elevated in cisplatin-resistant lung cancer cells, and overexpression or knockdown of Aurora-A resulted in increased or decreased cellular resistance to cisplatin. Furthermore, inhibition of Aurora-A reversed the migration ability of cisplatin-resistant cells.ConclusionsThe current findings suggest that high Aurora-A expression is correlated with cisplatin-based chemotherapeutic resistance and predicts poor patient survival in NSCLC. Aurora-A might serve as a predictive biomarker of drug response and therapeutic target to reverse chemotherapy resistance.