Open Access

Ionizing radiation promotes advanced malignant traits in nasopharyngeal carcinoma via activation of epithelial-mesenchymal transition and the cancer stem cell phenotype

  • Authors:
    • Zhongwu Su
    • Guo Li
    • Chao Liu
    • Shuling Ren
    • Yongquan Tian
    • Yong Liu
    • Yuanzheng Qiu
  • View Affiliations

  • Published online on: April 25, 2016     https://doi.org/10.3892/or.2016.4768
  • Pages: 72-78
  • Copyright: © Su et al. This is an open access article distributed under the terms of Creative Commons Attribution License.

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Abstract

Post-irradiation residual mass and recurrence always suggest a worse prognosis for nasopharyngeal carcinoma (NPC). Our study aimed to investigate the malignant behaviors of post-irradiation residual NPC cells, to identify the potential underlying mechanisms and to search for appropriate bio-targets to overcome this malignancy. Two NPC cell lines were firstly exposed to 60 Gy irradiation, and residual cells were collected. In our previous study, colony formation assay detected the radioresistance of these cells. Here, the CCK-8 assay examined the cell sensitivity to paclitaxel and cisplatin. Wound-healing and Transwell assays were performed to investigate cell motility and invasion capabilities. Inverted phase-contrast microscopy was used to observe and photograph the morphology of cells. Expression levels of epithelial-mesenchymal transition (EMT)-related proteins were detected by western blot assay in NPC cells and tissues. The mRNA levels of cancer stem cell (CSC)-related genes were detected via qRT-PCR. The results revealed that residual NPC cells exhibited enhanced radioresistance and cross-resistance to paclitaxel and cisplatin. Higher capacities of invasion and migration were also observed. An elongated morphology with pseudopodia formation and broadening in the intercellular space was observed in the residual cells. Downregulation of E-cadherin and upregulation of vimentin were detected in the residual NPC cells and tissues. CSC-related Lgr5 and c-myc were significantly upregulated in the CNE-2-Rs and 6-10B-Rs radioresistance cells. Higher proportions of Lgr5+ cells were observed in radioresistant cells via immunofluorescent staining and flow cytometry. In conclusion, our study demonstrated that residual NPC cells had an advanced malignant transition and presented with both EMT and a CSC phenotype. This provides a possible clue and treatment strategy for advanced and residual NPC.
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July-2016
Volume 36 Issue 1

Print ISSN: 1021-335X
Online ISSN:1791-2431

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Spandidos Publications style
Su Z, Li G, Liu C, Ren S, Tian Y, Liu Y and Qiu Y: Ionizing radiation promotes advanced malignant traits in nasopharyngeal carcinoma via activation of epithelial-mesenchymal transition and the cancer stem cell phenotype. Oncol Rep 36: 72-78, 2016.
APA
Su, Z., Li, G., Liu, C., Ren, S., Tian, Y., Liu, Y., & Qiu, Y. (2016). Ionizing radiation promotes advanced malignant traits in nasopharyngeal carcinoma via activation of epithelial-mesenchymal transition and the cancer stem cell phenotype. Oncology Reports, 36, 72-78. https://doi.org/10.3892/or.2016.4768
MLA
Su, Z., Li, G., Liu, C., Ren, S., Tian, Y., Liu, Y., Qiu, Y."Ionizing radiation promotes advanced malignant traits in nasopharyngeal carcinoma via activation of epithelial-mesenchymal transition and the cancer stem cell phenotype". Oncology Reports 36.1 (2016): 72-78.
Chicago
Su, Z., Li, G., Liu, C., Ren, S., Tian, Y., Liu, Y., Qiu, Y."Ionizing radiation promotes advanced malignant traits in nasopharyngeal carcinoma via activation of epithelial-mesenchymal transition and the cancer stem cell phenotype". Oncology Reports 36, no. 1 (2016): 72-78. https://doi.org/10.3892/or.2016.4768