Decreased Cytoplasmic X-box Binding protein-1 Expression Is Associated With Poor Prognosis and Overall Survival in Patients With Oral Squamous Cell Carcinoma

Clin Chim Acta. 2018 Apr;479:66-71. doi: 10.1016/j.cca.2018.01.001. Epub 2018 Jan 2.

Abstract

Introduction: Squamous cell carcinoma is the most common cancer of the oral cavity. In spite of advancements in surgical, chemoradiological and targeted therapies, these therapeutic strategies still have had little impact on survival rates. X-box binding protein-1 (XBP-1) is a potent transcription factor that is involved in the unfolded protein response (UPR) pathway, which itself is activated in response to endoplasmic reticulum stress as a method to restore cellular homeostasis. The role XBP-1 plays in oral squamous cell carcinoma (OSCC) has yet to be determined. In this study, we used molecular and immunohistochemical analyses to investigate the role of XBP-1 protein playing in the OSCC carcinogenesis.

Materials and methods: We used immunohistochemical analyses to investigate XBP-1 expression in 255 OSCC tissue specimens, as well as migration and invasion assays with XBP-1 siRNA transfection of oral cancer cell lines to confirm its role in OSCC.

Results: The XBP-1 immunostaining was dichotomized as low-level expression and high-level expression. We found that low-level cytoplasmic XBP-1expression was significantly correlated with larger tumor size (p=0.047), more advanced clinical stage (p<0.0001), lymph node metastasis (p=0.002), and shorter overall survival (p=0.011). Kaplan-Meier survival curves showed that low-level cytoplasmic XBP-1 expression was significantly correlated with shorter overall survival (p=0.031). The univariate Cox regression analysis revealed that cytoplasmic XBP-1 expression was a prognostic factor for overall survival of patients with OSCC. We also found that inhibition of XBP-1 promoted OSCC cell migration and invasion.

Conclusion: Our results suggest that XBP-1 expression may play an essential role in the pathogenesis of OSCC and that targeting XBP-1 may be a sound therapeutic strategy.

Keywords: Immunohistochemistry; Oral squamous cell carcinoma; Overall survival; Prognosis; Tissue microarray; X-box binding protein-1; XBP-1.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Carcinoma, Squamous Cell / genetics*
  • Carcinoma, Squamous Cell / pathology
  • Carcinoma, Squamous Cell / surgery
  • Cytoplasm / genetics*
  • Humans
  • Male
  • Middle Aged
  • Mouth Neoplasms / genetics*
  • Mouth Neoplasms / pathology
  • Mouth Neoplasms / surgery
  • Polymerase Chain Reaction
  • Prognosis
  • RNA, Small Interfering / pharmacology
  • Survival Analysis
  • Tumor Cells, Cultured
  • X-Box Binding Protein 1 / antagonists & inhibitors
  • X-Box Binding Protein 1 / genetics*

Substances

  • RNA, Small Interfering
  • X-Box Binding Protein 1