Aurora-A kinase regulates telomerase activity through c-Myc in human ovarian and breast epithelial cells

Aurora-A kinase is frequently overexpressed/activated in human ovarian and breast cancers. A rat mammary tumor model study indicates that alterations of Aurora-A are early events during mammary tumor development (T. M. Goepfert et al, Cancer Res., 62: 4115-4122, 2002), suggesting that Aurora-A plays a pivotal role in transformation. However, the molecular mechanism by which Aurora-A induces ovarian and breast cell transformation remains elusive. Here we show that ectopic expression of Aurora-A induces telomerase activity in human ovarian and breast epithelial cell lines HIOSE118 and MCF-10A. The mRNA and promoter activities of human telomerase reverse transcriptase (hTERT) are stimulated by Aurora-A. Furthermore, we have demonstrated that the c-Myc binding sites of hTERT promoter are required for Aurora-A-induced hTERT promoter activity. Ectopic expression of Aurora-A up-regulates c-Myc. Knockdown of c-Myc by RNA interference attenuates Aurora-A-stimulated hTERT expression and telomerase activity. To our knowledge, these findings demonstrate, for the first time, that Aurora-A induces telomerase activity and hTERT by up-regulation of c-Myc and provides an additional mechanism for the role of Aurora-A in malignant transformation in addition to its cell cycle control.