Phosphorylated Mnk1 and eIF4E are associated with lymph node metastasis and poor prognosis of nasopharyngeal carcinoma

PLoS One. 2014 Feb 14;9(2):e89220. doi: 10.1371/journal.pone.0089220. eCollection 2014.

Abstract

Nasopharyngeal carcinoma (NPC) is a head and neck malignant tumor rare throughout most of the world but common in Southeast Asia, especially in Southern China. The phosphorylation of eukaryotic translation initiation factor 4E (eIF4E) by MAP kinase-interacting kinases (Mnk) on Ser-209 promotes cellular proliferation, survival, malignant transformation and metastasis. However, whether the alterations of the expression of p-eIF4E and p-Mnk1 protein are associated with clinicopathologic/prognostic implication for NPC has not been reported. The purposes of the present study are to examine the expression of p-eIF4E and p-Mnk1 protein in NPC and non-cancerous nasopharyngeal epithelial tissues by immunohistochemistry and evaluate the association between the expression of p-eIF4E and p-Mnk1 protein and clinicopathological characteristics of NPC. The results showed that the positive percentage of p-Mnk1 and p-eIF4E proteins expression in NPC (83.5% and 75.4%, respectively) was significantly higher than that in non-cancerous nasopharyngeal epithelium (40.0% and 32.9%, respectively). The positive expression of p-eIF4E and p-Mnk1 in the NPC with cervical lymph node metastasis was significantly higher than those without lymph node metastasis. Additionally, p-eIF4E expression was more pronouncedly increased in metastatic NPC than the matched primary NPC. Increase of p-eIF4E and p-Mnk1 expression was significantly correlated inversely with overall survival. Spearman's rank correlation test further showed that expression of p-Mnk1 was strongly positive correlated with expression of p-eIF4E in NPC. The expression of p-Mnk1 and p-eIF4E in NPC was proved to be the independent prognostic factors regardless of lymph node metastasis, clinical stages and combination of radiotherapy and chemotherapy, histological type, age and gender by multivariate analysis. Taken together, high expression of p-Mnk1 and p-eIF4E might be novel valuable biomarkers to predict poor prognosis of NPC and therapeutic targets for developing the valid treatment strategies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Carcinoma
  • Eukaryotic Initiation Factor-4E / metabolism*
  • Female
  • Humans
  • Immunohistochemistry
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Kaplan-Meier Estimate
  • Lymphatic Metastasis / pathology*
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Nasopharyngeal Carcinoma
  • Nasopharyngeal Neoplasms / metabolism*
  • Nasopharyngeal Neoplasms / pathology*
  • Phosphorylation
  • Prognosis
  • Proportional Hazards Models
  • Protein Serine-Threonine Kinases / metabolism*
  • Recurrence
  • Young Adult

Substances

  • Eukaryotic Initiation Factor-4E
  • Intracellular Signaling Peptides and Proteins
  • MKNK1 protein, human
  • Protein Serine-Threonine Kinases

Grants and funding

The work was supported by grants from the National Natural Sciences Foundations of China (NO: 81071820;81272566) http://isisn.nsfc.gov.cn. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.