Hypofractionated radiotherapy induces miR-34a expression and enhances apoptosis in human nasopharyngeal carcinoma cells

  • Authors:
    • Zhixiong Long
    • Bin Wang
    • Dan Tao
    • Ying Huang
    • Zezhang Tao
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  • Published online on: September 17, 2014     https://doi.org/10.3892/ijmm.2014.1937
  • Pages: 1388-1394
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Abstract

Nasopharyngeal carcinoma (NPC) is a relatively radiosensitive disease. However, the therapeutic effects of radiotherapy are not always satisfactory due to radioresistance. The hypofractionated schema is currently widely used in clinical practice. In the present study, we investigated the effects of hypofractionated radiotherapy on NPC cells and explored the mechanisms involved. In addition, we aimed to determine the role of miR-34a in the effects of hypofractionated radiotherapy and whether these effects occur in a p53-dependent manner. For this purpose, we used CNE1 and CNE2 NPC cells which were subjected to hyperfractionated and hypofractionated radiotherapy. The viability of the cells was measured by MTT assay and acridine orange (AO) and ethidium bromide (EB) staining was used to observe morphological changes. In addition, Annexin V-propidium iodide (PI) staining and flow cytometry were used to determine the number of apoptotic cells and mRNA and protein expression was measured by qPCR and western blot analysis, respectively. The results revealed that hypofractionated radiotherapy enhanced apoptosis and increased the expression of miR-34a and p53 in the NPC cells. In addition, it stimulated p53 promoter activity and downregulated the protein expression of c-Myc in the human NPC cells. Furthermore, the knockdown of miR-34a suppressed the growth inhibitory effects induced by hypofractionated radiotherapy. Thus, our results suggest that the enhanced apoptosis of NPC cells may be associated with the miR-34a-mediated suppression of c-Myc in a p53-dependent manner.
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November-2014
Volume 34 Issue 5

Print ISSN: 1107-3756
Online ISSN:1791-244X

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Spandidos Publications style
Long Z, Wang B, Tao D, Huang Y and Tao Z: Hypofractionated radiotherapy induces miR-34a expression and enhances apoptosis in human nasopharyngeal carcinoma cells. Int J Mol Med 34: 1388-1394, 2014
APA
Long, Z., Wang, B., Tao, D., Huang, Y., & Tao, Z. (2014). Hypofractionated radiotherapy induces miR-34a expression and enhances apoptosis in human nasopharyngeal carcinoma cells. International Journal of Molecular Medicine, 34, 1388-1394. https://doi.org/10.3892/ijmm.2014.1937
MLA
Long, Z., Wang, B., Tao, D., Huang, Y., Tao, Z."Hypofractionated radiotherapy induces miR-34a expression and enhances apoptosis in human nasopharyngeal carcinoma cells". International Journal of Molecular Medicine 34.5 (2014): 1388-1394.
Chicago
Long, Z., Wang, B., Tao, D., Huang, Y., Tao, Z."Hypofractionated radiotherapy induces miR-34a expression and enhances apoptosis in human nasopharyngeal carcinoma cells". International Journal of Molecular Medicine 34, no. 5 (2014): 1388-1394. https://doi.org/10.3892/ijmm.2014.1937