Aurora-A regulates autophagy through the Akt pathway in human prostate cancer.

BACKGROUND: Aurora A kinase is frequently overexpressed in a variety of tumor types, including the prostate. However, the function of Aurora A in autophagy in prostate cancer has not been investigated. Here, we aimed to study the functioning mechanism and autophagy associated signaling pathways of Aurora A in prostate cancer.

METHODS: To investigate the biological function of Aurora A, down-regulation of Aurora A was performed followed by functional testing assays. Immunohistochemistry was used to detect the expression of Aurora A in human prostate cancer specimens. CCK8, Transwell, flow cytometric analysis and measurement of tumor formation in nude mice were performed to test the effects of Aurora A down-regulation in vivo and in vitro. Signaling pathway analysis was performed by using Western blot. Autophagy activity was measured by monitoring the expression levels of LC3-II.

RESULTS: Aurora A overexpression was significantly higher in human prostate cancer specimens than in BPH. Furthermore, Aurora A knockdown inhibited the proliferation of prostate cancer cells by suppressing the Akt pathway, indicating that Akt is a novel Aurora A substrate in prostate cancer. Additionally, Aurora A down-regulation prompts autophagy in prostate cancer cells. Most importantly, Aurora A ablation almost fully abrogates tumorigenesis in nude mice, suggesting that Aurora A is a key oncogenic effector in prostate cancer.

CONCLUSIONS: Taken together, our data suggest that Aurora-A plays an important role in the suppression of autophagy by inhibiting the phosphorylation of Akt, which in turn prevents autophagy-induced apoptosis in prostate cancer.