Radiotherapy is the primary treatment for nasopharyngeal carcinoma (NPC), but radioresistance severely reduces NPC radiocurability. Here, we have established a radio-resistant NPC cell line, CNE-2R, and investigate the role of miRNAs in radioresistance. The miRNAs microarray assay reveals that miRNAs are differentially expressed between CNE-2R and its parental cell line CNE-2. We find that miR-205 is elevated in CNE-2R. A target prediction algorithm suggests that miR‑205 regulates expression of PTEN, a tumor-suppressor. Introducing miR-205 into CNE-2 cells suppresses PTEN protein expression, followed by activation of AKT, increased number of foci formation and reduction of cell apoptosis postirradiation. On the other hand, knocking down miR-205 in CNE-2R cells compromises the inhibition of PTEN and increases cell apoptosis. Significantly, immunohistochemistry studies demonstrate that PTEN is downregulated at late stages of NPC, and that miR-205 is significantly elevated followed the radiotherapy. Our data conclude that miR-205 contributes to radioresistance of NPC by directly targeting PTEN. Both miR-205 and PTEN are potential predictive biomarkers for radiosensitivity of NPC and may serve as targets for achieve successful radiotherapy in NPC.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3356830 | PMC |
http://dx.doi.org/10.4161/cc.11.4.19228 | DOI Listing |
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