NF-κB induces abnormal centrosome amplification by upregulation of CDK2 in laryngeal squamous cell cancer

  • Authors:
    • Jian-Li Liu
    • Hui-Ping Ma
    • Xiu-Li Lu
    • Shao-Hua Sun
    • Xing Guo
    • Fu-Cai Li
  • View Affiliations

  • Published online on: July 15, 2011     https://doi.org/10.3892/ijo.2011.1125
  • Pages: 915-924
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Abstract

Centrosome amplification can drive chromosomal instability (CIN) which is a major source of tumor initiation. The present study aimed to investigate the impact of nuclear factor kappa B (NF-κB) on centrosome amplification of Hep-2 cells. Immunofluorescence was performed to display centrosomes. BAY11-7082 was used as an inhibitor of NF-κB to assess the inhibition of centrosome amplification, and cyclin-dependent kinase 2 (CDK2), ensuring cell cycle cycle coordination with centrosome cycle was detected by Western blotting. Furthermore, a 1556-bp fragment of the CDK2 promoter was analyzed using the TRANSFAC-TESS software. Luciferase assay, including a series of truncated CDK2 promoters and site mutations, was carried out to determine NF-κB binding sites in the CDK2 promoter. Electrophoresis mobility shift and chromatin immunoprecipitation assays were applied to confirm whether NF-κB indeed binds to the 5'-promoter region of the CDK2 gene. To reveal the clinical significance of CDK2 expression in laryngeal squamous cell cancer, mRNA and protein levels were assessed by RT-PCR and Western blotting, respectively. We found that the transcription factor NF-κB plays a role in centrosome amplification in Hep-2 cells. Centrosome amplification is reduced by inhibition of the NF-κB pathway. Moreover, expression of the p65 subunit of NF-κB is sufficient to promote centrosome amplification and increase in CDK2 protein levels. We further identified a functional NF-κB binding site located in the CDK2 promoter. Single mutation of the NF-κB site III (construct mutIII) however resulted in 76±5% (p<0.01) luciferase activity reduction. Electromobility shift assays and chromatin immunoprecipitaton results suggest that NF-κB indeed binds to this responsive element associating with CDK2 expression and centrosome amplification. RT-PCR and Western blotting results revealed that both mRNA and protein levels of CDK2 were significantly higher in tumor tissues than those in paired adjacent normal laryngeal tissues.

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October 2011
Volume 39 Issue 4

Print ISSN: 1019-6439
Online ISSN:1791-2423

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Spandidos Publications style
Liu J, Ma H, Lu X, Sun S, Guo X and Li F: NF-κB induces abnormal centrosome amplification by upregulation of CDK2 in laryngeal squamous cell cancer. Int J Oncol 39: 915-924, 2011.
APA
Liu, J., Ma, H., Lu, X., Sun, S., Guo, X., & Li, F. (2011). NF-κB induces abnormal centrosome amplification by upregulation of CDK2 in laryngeal squamous cell cancer. International Journal of Oncology, 39, 915-924. https://doi.org/10.3892/ijo.2011.1125
MLA
Liu, J., Ma, H., Lu, X., Sun, S., Guo, X., Li, F."NF-κB induces abnormal centrosome amplification by upregulation of CDK2 in laryngeal squamous cell cancer". International Journal of Oncology 39.4 (2011): 915-924.
Chicago
Liu, J., Ma, H., Lu, X., Sun, S., Guo, X., Li, F."NF-κB induces abnormal centrosome amplification by upregulation of CDK2 in laryngeal squamous cell cancer". International Journal of Oncology 39, no. 4 (2011): 915-924. https://doi.org/10.3892/ijo.2011.1125