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Cervical cancer is the second most common malignancy in women worldwide and always has recurrence owing to radioresistance. MicroRNA (miRNA or miR) has been identified to relate to the sensitivity of cancer radiotherapy. Here, we investigated the potential of miRNA-320 as a biomarker for radiosensitivity by targeting β-catenin in cervical cancer. A radioresistant cervical cancer cell line, C33AR, was established, and the radioresistance of C33AR cells was confirmed by a colony-formation assay. The expression of miRNA-320 was detected by reverse transcription-quantitative polymerase chain reaction, and compared between C33A and C33AR. β-catenin, the target of miRNA-320, was determined at the protein level by western blotting after transfecting the inhibitor of miRNA-320. The expression of miRNA-320 was markedly decreased in C33AR cells, which appeared to be more radioresistant, compared with its parental cell line C33A. Target prediction suggested that miRNA-320 negatively regulated the expression of β-catenin. Knockdown of β-catenin increased C33AR radiosensitivity, which revealed that the inhibition of β-catenin could rescue the miRNA-320-mediated cell radioresistance. On the other hand, overexpressing miRNA-320 increased C33AR radiosensitivity. In conclusion, miRNA-320 regulated the radiosensitivity of C33AR cells by targeting β-catenin. This finding provides evidence that miRNA-320 may be a potential biomarker of radiosensitivity in cervical cancer. [ABSTRACT FROM AUTHOR]

Protection of telomeres 1 (POT1) is a telomere-binding protein, which binds to the single-stranded DNA extensions of telomeres and regulates telomere length. Different POT1 mRNA variants were examined and compared with telomere length and radiosensitivity in colon and gastric adenocarcinoma cells. POT1 production and telomere lengths were assessed using 10 human cancer cell lines by quantitative polymerase chain reaction (qPCR). POT1 mRNA levels, which were relatively stable, were significantly correlated with telomere length in gastric cancer cells and colon cancer cells, except for HT29 (P<0.01). POT1 v5 indexes were closely associated with radiosensitivity in colon cancer cells and gastric cancer cells (P<0.05). In conclusion, POT1 may be a good marker for the examination of cell-specific telomere length and radiosensitivity. [ABSTRACT FROM AUTHOR]