miR-210 links hypoxia with cell cycle regulation and is deleted in human epithelial ovarian cancer

Antonis Giannakakis, Raphael Sandaltzopoulos, Joel Greshock, Shun Liang, Jia Huang, Kosei Hasegawa, Chunsheng Li, Ann O'Brien-Jenkins, Dionyssios Katsaros, Barbara L. Weber, Celeste Simon, George Coukos and Lin Zhang

volume 7 | issue 2

February 2008
Pages: 255 - 264

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Tumor growth results in hypoxia. Understanding the mechanisms of gene expression reprogramming under hypoxia may provide important clues to cancer pathogenesis. We studied miRNA genes that are regulated by hypoxia in ovarian cancer cell lines by TaqMan miRNA assay containing 157 mature miRNAs. MiR-210 was the most prominent miRNA consistently stimulated under hypoxic conditions. We provide evidence for the involvement of the HIF signaling pathway in miR-210 regulation. Biocomputational analysis and in vitro assays demonstrated that e2f transcription factor 3 (e2f3), a key protein in cell cycle, is regulated by miR-210. E2F3 was further confirmed to be downregulated at the protein level upon induction of miR-210. Importantly, we found remarkably high frequency of miR-210 gene copy deletions in ovarian cancer patients (64%, n=114) and that gene copy number correlates with miR-210 expression levels. Taken together, our results indicate that miR-210 plays a crucial role in tumor onset as a key regulator of the hypoxia response and provide evidence for a link between hypoxia and the regulation of cell cycle.

Authors

Antonis Giannakakis

Democritus University of Thrace, Alexandroupolis, Greece.